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A  TEXT-BOOK 

OF 

OPERATIVE  DENTISTRY 


LIST  OF  CONTRIBUTORS. 

J.  p.  BUCKLEY.  PH.  G.,  D.  D.  S., 

Professor  of  Materia  Medica  and  Therapeutics,  Chicago  College  of  Dental  Surgery. 

W.  A.  CAPON.  D.  D.  S.. 

Lecturer  and  Instructor  of  Dental  Ceramics,  Dental  Department,  University  of 
Pennsylvania. 

GEORGE  W.  COOK.  D.  D.  S., 

Dean  of  the  College  of  Dent;stry,  University  of  Illinois,  Chicago. 
FERDINAND  J.  S.  GORGAS.  A.  M..  M.  D..  D.  D.  S.. 

Dean  and  Professor  of  Principles  of  Dental  Science.  Oral  Surgery  and  Dental  Pros- 
thesis in  the  University  of  Maryland,  Dental  Department;  Author  of  "  Dental 
Medicine." 

ELLISON  HILLYER.  D.  D.  S.. 

Professor  of  Prosthetic  Dentistry  and  Orthodontia,  New  York  College  of  Dentistry, 

GEORGE  EDWIN  HUNT.  M.  D..  D.  D.  S.. 

Dean  and  Professor  of  Operative  Dentistry,  Dental  Pathology  and  Dental 

Hygiene,  Indiana  Dental  College,  Indianapolis. 
C.  N.  JOHNSON.  M.  A..  L.  D.  S..  D.  D.  S., 

Professor  of  Operative  Dentistry  in  the  Chicago  College  of  Dental  Surgery;  Editor 
of  "  The  Dental  Review." 

C.  EDMUND  KELLS.  JR..  D.  D.  S.. 

New  Orleans. 

GARRETT  NEWKIRK.  M.  D.. 

Member  of  the  California  State  Board  of  Dental  Examiners,  Former  Dean  and  Pro- 
fessor of  Operative  Dentistry,  College  of  Dentistry,  University  of  Southern 
California. 

JOHN  EGBERT  NYMAN.  D.  D.  S., 

Chicago. 

ALFRED  OWRE.  B.  A..  M.  D..  CM.,  D.  M.  D.. 

Dean  and  Professor  of  Operative  Dentistry  and  Metallurgy,  College  of  Dentistry, 
University  of  Minesota. 

JOHN  DEANS  PATTERSON.  D.  D.  S., 

Professor  of  Dental  Pathology,  Kansas  City  Dental  College. 

HERMANN  PRINZ.  M.  D..  D.  D.  S.. 

Professor  of  Materia  Medica,  Therapeutics  and  Pathology,  Dental  Department. 
Washington  University,  St.  Louis. 

HERBERT  A.  PULLEN,  D.  M.  D.. 

President  of  the  American  Society  of  Orthodontists,  1906-07;  Instructor  in  the 
Angle  School  of  Orthodontia.  Session  of  moo;  Member  of  the  New  York  State 
Dental  Society,  Buffalo  Dental  Association,  National  Dental  Association,  etc. 

CHARLES  R.  TURNER,  D.  D.  S  .  M.  D.. 

Professor  of  Mechanical  Dentistry  and  Metallurgy,  Department  of  Dentistry,  Uni- 
versity of  Pennsylvania. 

A.  E.  WEBSTER.  L.  D.  S.,  D.  D.  S..  M.  D.. 

Professor  of  Operative  Dentistry  and  Dental  Pathology  in  the  Royal  College  ai 
Dental  Surgeons  of  Ontario  ;  Editor  of  "  The  Dominion  Dental  Journal,"  etc. 

GEORGE  H.  WRIGHT,  D.  M.  D.. 

Former  Assistant  in  Embryology  and  Histology,  Harvard  Medical  School. 


A  TEXT-BOOK  OF 


OPERATIVE   DENTISTRY 


BY  VARIOUS  AUTHORS 


EDITED  BY 

C.  N.  JOHNSON.  M.  A.,  L.  D.  S..  D.  D.  S. 

PROFESSOR    OF    OPERATIVE    DENTISTRY    IN     THE    CHICAGO    COLLEGE    OF     DENTAL    SURGERY 
EDITOR    OF    THE    "DENTAL    REVIEW" 


THIRD  EDITION,  REVISED  AND  ENLARGED 


WITH  805  ILLUSTRATIONS 


PHILADELPHIA 

P.   BLAKISTON'S   SON   &  CO. 

1012   WALNUT   STREET 


^'    ys> 


zy^  -ti^oioi 


Copyright,  191 5,  by  P.  Blakiston's  Son   &  Co. 

Copyright,  1909,  by  P.  Blakiston's  Son  &  Co. 

Copyright,  1910,  by  P.  Blakiston's  Son  &  Co. 

Copyright,  191  i,  by  P.  Blakiston's  Son  &  Co. 

Reprinted,  October,  1911. 

Reprinted,  June,  1912. 

Reprinted,  April,  1913. 

Reprinted,  October,  1913. 

Reprinted,  Jui;y,  1915 

Reprinted,  August,  1917. 

Reprinted,  November,  1917- 

Reprinted,  May,  191 8. 

Reprinted,  August,  191 8. 

Reprinted,  October,  1918. 


THE     SIA1»X.E     PKESS     XORK     PA. 


PREFACE  TO  THE  THIRD  EDITION. 


The  preparation  for  the  third  edition  of  this  work  has  involved 
much  revision  in  some  of  the  chapters,  and  the  addition  of  two  en- 
tirely new  chapters — those  on  "The  Treatment  of  Impacted  Lower 
Third  Molars,"  and  "The  Application  of  the  Roentgen  Ray  to  Den- 
tistry." These  chapters  have  been  contributed  by  Dr.  C.  Edmund 
Kells,  whose  excellent  work  along  these  lines  makes  him  an  authority 
on  the  subjects.  The  addition  of  these  chapters  rounds  out  the 
work  into  a  more  comprehensive  treatment  of  the  entire  subject  of 
Operative  Dentistry,  and  makes  it  more  valuable  for  the  student  and 
practitioner. 

The  editor  announces  with  profound  sorrow  the  loss  by  death  of 
three  contributors  since  the  second  edition  was  issued,  Dr.  Geo.  W. 
Cook,  Ferdinand  J.  S.  Gorgas,  and  George  Edwin  Hunt.  In  each 
case  the  authors  revised  their  chapters  before  their  death. 

With  the  careful  revision  that  has  been  made  and  the  introduction 
of  new  matter  it  is  confidently  believed  that  the  present  edition  will  be 
even  more  acceptable  to  the  profession  than  the  previous  ones,  the 
reception  of  which  has  been  very  gratifying  to  all  those  concerned  in 
the  production  of  the  work. 

C.  N.  J. 

Chicago. 


PREFACE  TO  FIRST  EDITION 


In  preparing  this  book  for  the  profession  •  the  aim  has  been  to 
condense  the  latest  thought  on  the  various  subjects  into  the  closest 
possible  limit  consistent  with  a  clear  elucidation  of  the  ideas  presented. 
It  has  been  the  constant  effort  to  bring  the  work  strictly  up  to  date, 
and  with  the  rapid  evolution  of  dental  thought  in  progress  at  the 
present  time  this  has  been  no  small  task.  As  an  illustration  it  is  only 
necessary  to  mention  the  circumstance  that  one  entire  chapter — that 
by  Dr.  Nyman  on  the  gold  inlay — was  wholly  rewritten  after  it  was 
in  type  and  the  illustrations  made  for  it.  The  original  article  was 
discarded  as  being  out  of  date  the  moment  the  cast  method  became  a 
demonstrated  fact.  This  is  only  indicative  of  the  great  care  taken  by 
the  various  authors  in  the  revision  of  their  work,  and  for  which  the 
editor  wishes  at  this  time  to  express  his  great  appreciation. 

Particular  attention  is  called  to  the  illustrative  character  of  the 
work.  Most  of  the  cuts  were  made  specially  for  the  book,  and  many 
of  them  are  striking  m  their  origmality.  Those,  for  instance,  illustrating 
Dr.  Turner's  chapter  on  "The  Anatomy  of  the  Human  Teeth"  were 
made  from  photographs  of  natural  teeth,  a  typical  specimen  of  each 
tooth  being  selected  for  this  purpose  and  photographed  on  its  different 
surfaces.  The  effect  has  been  to  present  something  perfectly  true  to 
nature. 

Mention  might  be  made  of  distinguishing  features  in  each  chapter 
in  the  book,  but  this  would  appear  unnecessary  with  the  work  in  the 
reader's  hands.  It  seems  appropriate,  however,  to  call  attention  to 
Dr.  Pullen's  chapter  on  "Orthodontia"  which  we  believe  is  one  of 
the  most  concise  and  practical  presentations  of  this  important  subject 
that  has  yet  appeared. 

To  the  contributors  the  editor  feels  under  deep  obligation  for  their 
cordial  cooperation  in  preparing  the  work,  and  to  the  publishers 
for  their    uniform  courtesy  and  painstaking  care  in  every  detail  of 

publication. 

C.  N.  J. 
Chicago. 


Vll 


CONTENTS. 


PAGE 

Introduction, xiii 

BY   C.    N.    JOHNSON,    M.    A.,    L.    D.    S.,    D.    D.    S. 

CHAPTER  I 
The  Anatomy  of  the  Human  Teeth i 

BY   CHARLES    R.    TURNER,    D.    D.    S.,    M.    D. 

CHAPTER  II 
The  Histology  of  the  Human  Teeth, 60 

BY   CHARLES   R.    TURNER,    D.    D.    S.,    M.    D. 

CHAPTER  III 
Hygiene  and  Arrangement  of  Light  in  the  Operating-room, 85 

BY   C.    N.   JOHNSON,    M.    A.,    L.    D.    S.,   D.   D.    S. 

CHAPTER  IV 
Asepsis  in  the  Operating-room 89 

BY   A.   E.    WEBSTER,    M,    D.,    L.    D.    S.,    D.    D.    S. 

CHAPTER  V 
Hygiene  of  the  Mouth,      97 

BY   GEORGE   H.    WRIGHT,    D.    M.   D. 

CHAPTER  VI 
Dental  Caries, 119 

BY   C.    N,   JOHNSON,    M.    A.,    L.    D.    S.,    D.    D.    S. 

CHAPTER  VII 
Examination  of  Teeth  for  the  Discovery  of  Carious  Cavities, 131 

BY   GARRETT   NEWKIRK,    M.    D. 

CHAPTER  VIII 
Separation  of  Teeth  Preparatory  to  Operating  on  Cavities  in  the  Proximal 

Surfaces, 137 

BY   GARRETT   NEWKIRK,    M,   D. 

CHAPTER  IX 
Exclusion  of  Moisture  from  the  Teeth  during  Operations,      I49 

BY   GEORGE   EDWIN   HUNT,    M.   D.,    D.    D.   S. 

ix 


X  CONTENTS. 

CHAPTER  X 

PAGE 

Preparation  of  Cavities  for  Fillings, 165 

BY   A.    E.    WEBSTER,    M.    D.,    L.    D.    S  ,    D.    D.    S. 

CHAPTER  XI 
The  Treatment  of  Sensitive  Dentin, 219 

BY   J.    P.    BUCKLEY,    PH.    G.,    D.    D.    S. 

CHAPTER  XII 
Filling  Materials:  Their  Characteristics,  Indications  for  Their  Use  and  the 

Methods  of  Manipulation, 229 

BY   ALFRED    OWRE,    B.    A.,    M.    D.,    C.    M.,   D.    M.    D. 

CHAPTER  XIII 
The  Use  of  the  Matrix  in  Filling  Teeth, 259 

BY   GARRETT   NEWKIRK,    M.    D. 

CHAPTER  XIV 
Inlays 267 

BY   C.    N.    JOHNSON,    M.    A.,    L.    D.    S.,    D.    D.    S. 

CHAPTER  XV 
Preparation  of  Cavities  for  Inlays 271 

BY   C.    N.    JOHNSON,    M.    A.,    L.    D.    S.,    D.    D.    S. 

CHAPTER  XVI 
The  Porcelain  Inlay,      281 

BY    W.    A.    CAPON,    D.    D.    S, 

CHAPTER  XVII 
Construction  of  Gold  Inlays, 305 

BY   JOHN   EGBERT   NYMAN,    D.    D.    S. 

CHAPTER  XVIII 
The  Treatment  of  Exposed  or  Nearly  Exposed  Pulps, 319 

BY   J.    P.    BUCKLEY,    PH.    G.,    D.    D.    S. 

CHAPTER  XIX 
The  Anesthetization  and  Devitalization  of  Pulps,  Their  Removal  and  the 

Subsequent  Treatment, 325 

BY   J.    p.   BUCKLEY,    PH.    G.,    D.    D.    S. 

CHAPTER  XX 
The  Treatment  of  Ordinary  Pericementitis, 343 

BY   J.    P.   BUCKLEY,    PH.    G.,    D.    D.    S. 

CHAPTER  XXI 
The  Chemistry  of  Pulp  Decomposition 349 

BY   J.    p.   BUCKLEY,    PH.    G.,   D.    D.    S. 


CONTENTS.  XI 

CHAPTER  XXII 

PAGE 

The  Treatment  of  Putrescent  Pulps;  Acute  and  Chronic  Alveolar  Abscess, 

with  Complications;  and  the  Filling  of  Root  Canals,       355 

BY   J.    P.   BUCKLEY,    PH.    G.,    D.    D.    S. 

CHAPTER  XXIII 
The  Causes  and  Treatment  of  Discolorations  of  Teeth 375 

BY   J.    P.   BUCKLEY,    PH.    G.,    D.    D.    S. 

CHAPTER  XXIV 
The  Treatment  of  Children's  Teeth, 385 

BY   C.    N.   JOHNSON,    M.    A.,    L.    D.    S.,    D.    D.    S. 

CHAPTER  XXV 
Local  Anesthesia, 393 

BY    HERMANN    PRINZ,    M.    D.,    D.    D.    S. 

CHAPTER  XXVI 
The  Extraction  of  Teeth 419 

BY   FERDINAND   J.    S.    GORGAS,    A.    M.,    M.    D.,    D.    D.    S. 

CHAPTER  XXVII 
The  Treatment  of  Impacted  Lower  Third  Molars, 459 

BY   C.    EDMUND    KELLS,    JR.,    D.    D.    S. 

CHAPTER  XXVIII 
The  Planting  of  Teeth,      . 473 

BY   C.    EDMUND    KELLS,    JR.,    D.    D.    S. 

CHAPTER  XXIX 
Pyorrhea  Alveolaris, 487 

BY   JOHN    DEANS    PATTERSON,    D.    D.    S. 

CHAPTER  XXX 
Erosion, 507 

BY   GEO.    W.    COOK,    D.    D.    S. 

CHAPTER  XXI 
The  Management  of  an  Office  Practice, 519 

BY   ELLISON    HILDYER,    D.    D.    S. 

CHAPTER  XXXII 
The  Application  of  the  Roentgen  Ray  to  Dentistry, 541 

BY   C.    EDMUND    KELLS,    JR.,    D.    D.    S. 

CHAPTER  XXXIII 

Orthodontia, 603 

by  herbert  a.  pullen,  d.  m.  d. 
Index, 881 


INTRODUCTION. 


Operative  Dentistry  may  be  defined  as  the  science  and  art  which 
aims  at  the  preservation  of  the  natural  teeth  in  a  state  of  health  and 
beauty.  Its  highest  office  is  to  prevent  disease  or  deformity,  but 
where  either  of  these  has  already  occurred  it  is  then  its  function  to 
remedy  the  evil,  and  check  its  further  progress.  The  dentist  who 
does  the  best  for  his  patient  is  the  one  who,  in  addition  to  the  develop- 
ment of  the  highest  manipulative  skill,  studies  most  care.fully  the 
conditions  surrounding  the  field  of  his  operations.  To  fill  a  cavity 
in  a  tooth  in  the  most  perfect  manner  possible,  when  the  surrounding 
tissues  are  in  an  abnormal  condition,  without  a  recognition  of  this 
fact  and  the  most  careful  attention  to  the  abnormality,  is  far  from 
good  practice.  To  attempt  to  remedy  any  disorder  in  the  mouth  by 
confining  attention  solely  to  the  immediate  seat  of  the  trouble  is  fre- 
quently to  court  failure.  The  human  economy  is  so  complicated  that 
cause  and  effect  are  often  remote  from  each  other,  and  the  practitioner 
who  does  the  best  service  to  his  patient  is  the  one  who  in  addition 
to  being  an  acute  observer  extends  his  observation  over  the  widest 
field. 

The  conscientious  dentist,  when  he  finds  himself  baffied  in  dis- 
covering the  cause  or  relieving  the  symptoms  of  any  affection  of  the 
mouth  will  not  hesitate  to  call  in  consultation  a  specialist  in  dentistry 
or  medicine  as  the  case  indicates,  and  particularly  is  it  desirable  in 
instances  of  peculiar  idiosyncrasies  to  consult  with  the  family  physician 
of  the  patient. 

No  individual  practicing  a  profession  like  dentistry  should  think 
lightly  of  his  obligations,  and  no  practitioner  can  properly  fulfill  his 
obligations  without  developing  the  habit  of  painstaking  care  in  all 
his  work  whether  of  diagnosis  or  treatment.  It  should  early  be 
recognized  by  the  young  practitioner  that  dentistry  demands  of  those 
who  aim  to  excel  in  its  practice  a  more  diversified  order  of  talent  than 
any  other  calling.  To  be  a  good  dentist  an  individual  should  develop 
the  scientist's  attitude  toward  the  intimate  and  sometimes  intricate 
relationship  between  cause  and  effect,  he  should  be  a  close  observer 
of  phenomena,  a  mechanician  of  the  first  order,  an  artist  with  the  sense 

xiii 


XIV  INTRODUCTION. 

of  harmony  highly  cultivated,  a  physician  in  his  diagnosis  of  disease, 
a  humanitarian  in  his  ministrations  to  others,  and  above  all  a  cultured 
gentleman  of  the  highest  mental  and  moral  fiber. 

This  does  not  imply  that  in  the  beginning  he  must  be  endowed 
with  great  brain  capacity  or  natural  attributes  of  an  unusual  char- 
acter. The  encouraging  thing  about  dentistry  is  that  most  of  the 
qualities  necessary  for  achievement  are  capable  of  cultivation,  and 
the  man  who  will  apply  himself  with  sufficient  zeal  and  perseverance 
is  certain  of  at  least  a  reasonable  measure  of  success.  The  chief 
requisite  is  the  patience  to  plod. 

If  every  dentist  would  bring  to  his  work  a  real  sincerity  of  purpose 
to  serve  his  patients  to  the  highest  possibilities  of  his  art,  the  future 
of  the  profession  would  be  secure.  There  would  be  less  need  than 
there  is  today  of  artificial  teeth,  and  the  full  functional  use  of  the 
natural  organs  in  mastication  and  in  harmony  of  expression  would 
be  more  generally  recognized  and  appreciated.  As  we  develop 
dentistry  along  the  lines  of  prevention  and  conservation  we  shall 
bring  it  nearer  and  nearer  to  its  highest  mission.  To  do  the  greatest 
good  to  the  largest  number,  to  do  this  good  without  thought  of  self 
advancement,  to  work  for  the  love  of  it  and  for  the  benefit  it  brings 
to  humanity — this  is  the  acme  of  faithful  service  and  the  only  kind  of 
effort  which  will  bring  permanent  satisfaction.  Unless  a  dentist  is 
willing  to  do  this  he  will  fall  short  of  all  that  his  profession  has  to  offer 
him,  if  he  does  it  he  may  be  certain  of  an  encouraging  measure  of 
attainment. 

But  to  accomplish  anything  of  note  he  must  be  progressive.  The 
methods  of  yesterday  will  not  suffice  for  today.  No  profession  is 
developing  more  rapidly  than  dentistry  and  he  who  would  give  the 
best  service  must  ever  be  alive  to  the  latest  advances.  The  foremost 
thinkers  of  the  profession  are  constantly  placing  their  ideas  before 
their  fellow  practitioners,  and  the  man  who  keeps  abreast  must  be 
alert  to  avail  himself  of  the  results  of  their  matured  thought.  It  is 
with  the  purpose  of  presenting  this  thought  in  the  most  condensed 
form  as  it  relates  to  the  different  departments  of  operative  dentistry 
that  the  present  volume  is  issued. 


OPERATIVE  DENTISTRY. 


CHAPTER  I. 
THE  ANATOMY  OF  THE  HUMAN  TEETH. 

BY  CHARLES  R.  TURNER,  D.  D.  S.,  M.  D. 

The  teeth  of  man  are  hard  masses  of  calcified  tissue  attached  to 
the  mandible  and  maxilla  and  having  as  their  chief  function  partici- 
pation in  thework  of  his  masticatory  apparatus.  His  food,  as  intro- 
duced into  the  mouth,  the  beginning  of  the  digestive  tract,  consists  of 
articles  of  various  degrees  of  physical  consistency.  In  order  that 
this  may  be  prepared  for  subsequent  stages  in  the  digestive  process, 
much  of  it  must  be  mechanically  subdivided  into  particles  of  convenient 
size  to  go  through  the  alimentary  canal  and  be  acted  upon  by  the  di- 
gestive ferments  and  solvents.  Such  subdivision  is  performed  in  the 
mouth  by  the  act  of  mastication  and  it  is  with  this  function  that  the 
teeth  are  chiefly  concerned.  They  afford  hard  opposed  surfaces 
which  are  brought  into  contact  in  the  approximation  of  the  jaws  by 
the  muscular  apparatus  and  by  this  means  the  food  is  cut  or  crushed 
into  particles  of  the  desired  size. 

The  teeth  also  have  a  functional  relationship  with  the  apparatus 
by  which  voice  and  speech  are  produced  and  bear  a  cosmetic  relation 
to  the  features  of  the  face. 

The  adult  human  denture  consists  normally  of  thirty-two  teeth 
which  are  divided  in  number  equally  between  the  upper  and  the  lower 
jaw.  These  are  known  as  the  permanent  teeth,  in  contra-distinction 
to  the  temporary  or  deciduous  teeth  which  serve  for  purposes  of  mas- 
tication during  the  earlier  years  of  life  and  are  subsequently  exfoliated 
to  give  place  to  their  permanent  successors. 

The  permanent  teeth  are  divided  anatomically  into  classes  and 
these  divisions  largely  correspond  with  their  functions  as  portions 
of  the  masticatory  apparatus.     Thus,  there  are  eight  incisors,  which 

Note. — The  author  desires  to  acknowledge  his  indebtedness  for  Figs,  i  to  84  inclu- 
sive to  Dr.  George  J.  Paynter,  of  the  Department  of  Dentistry,  University  of  Pennsyl- 
vania, who  selected  and  dissected  the  specimens,  and  to  the  Department  of  Dentistry, 
University  of  Pennsylvania,  for  whom  the  photographs  were  made,  for  permission  to 
reproduce  them. 


2  THE    ANATOMY    OF    THE    HUMAN    TEETH 

serve  in  the  incising  of  the  food;  four  cuspids,  whose  chief  function 
in  the  carnivorous  animals  is  to  pierce  and  hold  the  food,  a  function 
wholly  rudimentary  with  man;  eight  bicuspids,  which  are  intermedi- 
ate in  position  and  function  between  the  cuspids  and  the  molars, 
and  lastly  twelve  molars  which  are  the  crushing  and  grinding  teeth 
proper.    The  formula  for  the  permanent  human  dentition  is  expressed : 

l'-\       C'^,       b'-',      m3-3  =  3, 

2-2  I-I  2-2  ^-^ 

The  deciduous  denture  consists  of  twenty  teeth — eight  incisors, 
four  cuspids  and  eight  molars. 

As  all  the  teeth  possess  certain  characteristics  in  common  it  will 
be  well  to  refer  to  these  before  undertaking  a  description  of  the  in- 
dividual teeth. 

The  crown  of  a  tooth  is  that  portion  which  projects  beyond  the 
gum  margin  and  is  normally  covered  with  enamel.  The  root  or  roots 
of  the  tooth  are  imbedded  in  the  alveolar  process  and  are  attached 
thereto  by  a  fibrous  membrane,  the  pericementum.  The  root  and 
crown  of  a  tooth  unite  at  its  neck,  a  point  which  corresponds  to  the 
point  of  juncture  of  the  enamel  and  the  cementum.  This  is  also  called 
the  cervix  and  also  the  gingival  margin  of  the  crown.  The  sharp- 
ened extremity  of  a  root  is  known  as  its  apex,  and  this  is  the  seat  of  an 
opening  which  transmits  the  nerves  and  blood  vessels  of  the  pulp  of  the 
tooth  and  is  known  as  the  apical  foramen.  The  surface  of  a  tooth 
which  comes  into  contact  with  the  corresponding  surface  of  teeth 
in  the  opposing  jaw  is  referred  to  as  the  occlusal  surface.  This  term 
is  also  applied  to  the  analogous  portion  of  the  incisor  teeth  although 
strictly  speaking  it  should  only  apply  to  that  of  the  lower  incisors,  in- 
asmuch as  this  edge  of  the  incisors  of  the  upper  jaw  does  not  touch 
the  teeth  of  the  lower  jaw,  when  the  teeth  are  in  occlusal  contact,  but 
normally  is  only  brought  into  this  relationship  when  the  mandible  is 
protruded.  This  is  also  referred  to  as  the  incisive  edge  of  the  incisors. 
Molar  and  bicuspid  teeth  have  large  tubercles  upon  their  occlusal 
surfaces  and  these  are  known  as  cusps.  The  adjoining  surfaces  of 
teeli  are  known  as  their  proximal  surfaces,  the  most  prominent  point 
of  which  is  called  the  angle  of  the  tooth.  If  a  vertical  plane  is  passed 
between  the  central  incisors  of  both  jaws,  those  proximal  surfaces  of 
the  teeth  which  are  directed  toward  this  are  known  as  mesial  surfaces, 
while  those  proximal  surfaces  directed  away  from  it  are  known  as 
distal  surfaces.  The  surfaces  of  the  six  anterior  teeth  of  each  series 
which  are  in  relation  with  the  lips  are  called  labial,  while  the  corre- 


THE    UPPER    CENTRAL    INCISOR.  3 

spending  surfaces  of  the  remaining  teeth  which  are  in  relation  with  the 
cheeks  are  called  buccal  surfaces.  Those  surfaces  of  the  teeth  which 
are  directed  inward  toward  the  cavity  of  the  mouth  are  known  as  their 
lingual  surfaces. 

The  surface-form  and  internal  anatomy  of  the  permanent  teeth 
will  now  be  given  in  detail. 

THE  UPPER  CENTRAL  INCISOR. 

The  crown  of  this  tooth  is  wedge-shaped;  the  base  of  the  wedge 
is  at  its  cervical  margin  from  which  the  broad  labial  and  lingual  sur- 
faces converge  to  a  straight  cutting  edge. 


Fig.  I. — Left  Upper  Central  Incisor. 
Labial  Surface. 


Fig.  2. — Left  Upper  Central  Incisor. 
Lingual  Surface. 


The  Labial  Surface  (Fig.  i). — Irregularly  quadrilateral  in  shape, 
this  surface  has  four  margins.  The  incisive  edge  which  forms  its 
lower  margin  is  nearly  straight;  it  is  marked  in  the  newly  erupted 
tooth  by  two  developmental  grooves  which  disappear  early  in  life  be- 
cause of  the  wearing  down  of  the  three  tubercles  which  are  found  on 
this  edge.     The  mesial   margin  is  nearly  straight  or  may  be  a  long 


4  THE  ANATOMY  OF  THE  HUMAN  TEETH. 

curve;  the  cervical  border  is  convex  rootward,  while  the  distal  margin 
is  more  convex  than  the  mesial  and  is  a  little  shorter.  The  surface 
itself  is  convex  from  the  cervix  to  the  incisive  edge,  the  lower  portion 
of  it  being,  however,  nearly  flat,  while  that  portion  near  the  cervix  is 
more  curved  and  is  marked  by  a  cervical  ridge.  This  face  of  the  crown 
is  convex  from  side  to  side  and  is  marked  by  two  longitudinal  grooves 
which  correspond  to  the  lines  of  union  of  the  three  developmental  lobes 
of  the  crown. 

The  Lingual  Surface  (Fig.  2).— This  is  irregularly  triangular,  the 
mesial  and  distal  margins  uniting  with  the  cervical  to  form  a  rounded 


Fig. 


-Left  Upper  Central  Incisor. 
Mesial  Surface. 


Fig.  4. — Left  Upper  Central  Incisor. 
Distal  Surface. 


apex,  while  the  base  of  the  triangle  is  formed  by  the  incisive  margin. 
The  mesial  and  distal  margins  are  marked  by  rounded  ridges  of  enamel 
which  extend  from  the  angles  of  the  crown  in  a  graceful  curve  rootward 
to  unite  with  the  cervical  ridge.  The  mesial  is  slightly  the  longer  of 
these  two.  The  cervical  is  more  pronounced  than  the  other  marginal 
ridges.  It  is  sometimes  cut  near  its  center  by  a  fissure  and  sometimes 
it  is  the  seat  of  a  rounded  elevation  of  enamel,  the  cingulum.     The 


THE    UPPER    CENTRAL    INCISOR. 


I'lG.  5. — Lclt  upper  Ceuiral 
Incisor.     Incisal  View. 


lingual  surface  is  concave    inciso-gingivally   and    mesio-distally.     Its 
center  is  occupied  by  a  pronounced  fossa,  the  lingual  fossa,  which  is 
traversed    by    two    longitudinal    grooves. 
Occasionally  a  lingual   pit  is  present  and 
this  occupies  a  position  at  the  juncture  of 
the  cervical  ridge  and  the  lingual  fossa. 

The  Mesial  Surface  (Fig.  3). — Being 
shaped  like  a  spear-head  or  irregularly  tri- 
angular in  outline,  this  surface  has  three 
margins.  The  labial  presents  a  long  curve 
ending  in  the  mesial  angle  of  the  tooth  and 
is  shorter  than  the  lingual  which  it  meets  at 
this  point.     Both  are  bowed    in   a  labial 

direction  and  the  labial  margin  is  the  more  pronounced,  the  lingual 
being  rounded  and  marking  less  distinctly  the  boundary  of  the  surface. 

The  cervical  margin  is  concave  in  an 
incisal  direction  and  at  its  terminations 
unites  with  both  the  labial  and  lingual  bor- 
ders at  an  acute  angle.  Near  tlie  incisive 
edge  the  surface  is  convex  but  this  convex- 
ity decreases  as  the  root  is  approached  and 
the  surface  becomes  either  a  plane  or  is 
marked  by  a  slight  depression  at  the  gingival 
margin.  The  most  prominent  point  of  the 
surface  is  located  one-third  the  distance 
from  the  mesial  angle  and  this  establishes 
the  point  of  contact  with  the  central  incisor 
of  the  opposite  side. 

TJie  Distal  Surface  (Fig.  4).— While 
this  is  of  the  same  general  shape  as  the 
mesial  surface,  it  is  slightly  smaller  because 
of  the  location  of  the  distal  angle  nearer  to 
the  cervix.  Its  margins  are  less  distinct 
and  the  surface  is  more  rounded  and  the 
point  of  contact  with  the  lateral  incisor  is 
relatively  nearer  the  cervix. 

The  Incisive  Edge   (Fig.   5). — The  in- 
cisive edge  is  formed  by  the   intersection 
of  the  planes  of  the  labial  and  lingual  sur- 
faces of  the  crown.     These  do  not  meet  at  an  acute  angle  but  their 
line  of  intersection  is  somewhat  rounded.     This  edge  extends  from 


Fig.  6. — Left  Upper  Central 
Incisor.  Longitudinal  section 
cut  labio-lingually  showing 
pulp  cavity. 


THE    ANATOMY    OF    THE    HUMAN   TEETH. 


the  mesial  to  the  distal  angle,  usually  almost  in  a  straight  line.     In 
young  subjects  it  is  marked  by  the  developmental  grooves,  but  these 

usually  disappear  from  the  wearing  of  the 
■^■■■■■l^^l  surfaces.  When  the  crov^n  is  viewed  from 
■^^  ^^B      below,  the  line  of  the  incisive  edge  is  oc- 

B  _     ,,'.  ^1      casionally  bowed  in  a  labial  direction. 

t.    ■  '^^SdK^H  -^^^  Cervical  Margin. — Beginning  at  the 

^B^  jjj^^^HJ^H  mesio-labial  portion  of  this  line,  it  extends 
^^■jj^^^^^^^H  with  an  upward  curve  upon  the  labial  sur- 
^^^^^^^^^^P      face,  downward  on  the  distal,  upward  on 


Fig.  8. — Left  Upper  Central 
Incisor.  Cross-section  at  cer- 
vix showing  small  pulp  cavity 
in  old  tooth.  Looking  crowrn- 
ward. 


Fig.  7.— Left  Upper  Central  the    lingual,    and  downward   again  on  the 

Incisor.     Cross-section   at  cer-  ;^    ^       ^j^         QJ^t    of    beginning.      It    is 

vix  showing  pulp  chamber  m  ^        _  .  . 

crown.    Looking  crownward.     marked  by  the  bulging  of  the  cervical  ridge 

on  the  labial  and  lingual  surfaces.     While  there  is  usually  a  well- 
defined   constriction  on   the  tooth   at  this 

point,  the  neck  of  the  tooth  is  not  so  marked 

as  in  some  of  the  distal  teeth. 

The  Root. — This  is  conical  in  shape,  and 

when  viewed  from  the  labial  surface  (Fig. 

i)  its  sides  converge  in  almost  straight  lines 

to  a  rounded  point;  but  viewed  from  the 

mesial  (Fig.  3)  or  distal  side  the  outlines  of 

the  root  curve  to  a  rounded  point.    When 

viewed  in  cross-section  at  the  neck  the  labio- 

lingual  diameter  of  the  root  is  greater  than 

the  mesio-distal  and  the  root  outline  is  that 

of  a  rounded  triangle  with  its  sides  corresponding  to  the  labial,  mesial, 

and  disto-lingual  faces  of  the  root.  Of  these 
the  mesial  is  the  longest  and  nearly  straight,  the 
labial  and  disto-lingual  being  approximately 
equal  in  length  but  the  labial  is  the  most 
curved  of  all. 

The  Pulp  Cavity. — The  form  of  the  pulp 
cavity  of  the  central  incisor  corresponds  in 
general  v^^ith  the  external  form  of  the  tooth 

JVd7„;!'°'oorsec.io"^    itself  (Fig.  6).     It  is  divisible  into  the  pulp 

made  at  middle  of  crown    chamber  and  the  pulp  canal,  but  the  line  of 

(looking    rootward)  showing      ....  .  ..      i        i  i     j         -t-u  i 

form  of  pulp  chamber,  division   IS   not  clearly    marked.      1  he  pulp 

chamber  occupies  the  crown  of  the  tooth  and, 

as  seen  in  a  labio-lingual  section  of  the  tooth  (Fig.  6) ,  follows  the  form 

of  the  crown  closely.     The  pulp  canal  is  conic  in  form,  with  its  base 


THE    UPPER    LATERAL    INCISOR.  7 

joining  the  pulp  chamber  and  its  apex  reaching  the  apex  of  the  root 
where  it  terminates  in  the  apical  foramen.  In  a  cross-section  of  the 
tooth-crown  the  flattening  out  of  the  incisal  end  of  the  pulp  chamber 
to  follow  the  incisive  edge  of  the  tooth,  is  seen.  (Fig.  9.)  The  portions 
extending  in  the  direction  of  the  angles  of  the  tooth  are  known  as  the 
"horns"  of  the  pulp.     In  the  young  subject  there  are  three  concavities 


Fig.  10. — Right  Upper  Lateral  Incisor.  Fig.  ii. — Right  Upper  Lateral  Incisor. 

Labial  Surface.  Lingual  Surface, 

in  its  occlusal  end,  corresponding  to  the  three  tubercles  and  the  three  de- 
velopmental centers  of  the  incisive  edge  of  the  crown.  A  cross-section 
of  the  root  at  the  cervix  shows  the  pulp  cavity  almost  circular  in  outline 
(Fig.  8),  and  this  form  characterizes  it  to  the  end  of  the  root.  The 
pulp  cavity  of  this,  as  of  all  the  teeth,  diminishes  in  size  from  the  time 
of  completion  of  the  root  through  old  age  because  of  the  deposit  of 
dentin  upon  its  walls  (Fig.  8). 

THE  UPPER  LATERAL  INCISOR. 

The  Labial  Surface  (Fig.  10). — This  surface  is  somewhat  similar  in 
outline  to  that  of  the  central  incisor  except  that  it  is  smaller,  being 
narrower  from  side  to  side  and  shorter,  and  its  distal  angle  is  more 
rounded.      It  is  bordered  by  four  margins.      The  incisive  margin  is 


8 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


almost  straight,  being,  however,  inclined  slightly  downward  in  the 
direction  of  the  median  line  and  in  the  young  tooth  is  marked  by 
developmental  grooves  which  are  less  prominent  than  those  of  the 
central  incisor.  The  mesial  margin  is  nearly  straight  from  the  mesial 
angle  to  the  cervix,  being  sometimes,  however,  slightly  concave  which 
causes  a  hook-like  appearance  to  this  surface  of  the  tooth.  The  cer- 
vical margin  is  markedly  convex  rootward  since  the  tooth  is  narrower 
than  the  central  incisor,  while  the  distal  margin  is  also  made  convex 


Fig.  12. — Right  Upper  Lateral  Incisor. 
Mesial  Surface. 


Fig.  13. — Right  Upper  Lateral  Incisor. 
Distal  Surface. 


from  the  projection  of  its  distal  angle.  The  latter  is  longer  than  the 
mesial  margin  cicumferentially,  but  a  straight  line  drawn  from  the 
distal  angle  to  the  cervix  shows  that  this  portion  of  the  face  is  shorter 
than  the  mesial  portion.  The  labial  surface  is  more  rounded  in  every 
way  than  that  of  the  central.  The  cervical  ridge  and  developmental 
grooves  are  present  but  are  not  so  pronounced. 

The  Lingual  Surface  (Fig.  11). — Like  that  of  the  central  incisor, 
this  surface  is  usually  slightly  concave,  which  is  due  to  the  projection 
of  the  mesial,  distal  and  cervical  marginal  ridges.  In  outline  it  is 
nearly  triangular.     The  incisive  margin  is  the  same  shape  as  that  de- 


THE    UPPER    LATERAL    INCISOR.  9 

scribed  for  the  labial  surface.  The  mesial  and  distal  marginal  ridges 
are  well  marked  and  unite  with  the  cervical  ridge.  Both  the  mesial 
and  distal  margins  are  usually  convex  although  the  mesial  may  be  almost 
straight.  The  distal  is  much  shorter.  The  cervical  margin  is  formed 
by  the  cervical  ridge  and  is  more  frequently  the  seat  of  a  cingulum 
than  that  of  the  central  incisor.  While  the  surface  is  usually  con- 
cave in  all  directions,  in  some  instances  it  may  be  almost  flat.  There 
is  normally  a  well-defined  fossa  and  in  some  cases  this  latter  is  marked 
with  a  longitudinal  ridge  corresponding  to  that  on  the  labial  face. 

The  Mesial  Surface  (Fig,  12). — Shaped  like  an  arrow-head,  the 
cervical  margin  being  concave,  the  labial  margin  of  this  surface  is  con- 
vex with  a  long  curve.  The  lingual  margin  is  less  distinctly  marked,  is 
concave,  and  unites  with  the  labial  at  the  mesial  angle  of  the  crown. 
The  surface  is  convex  in  its  lower  two-thirds 
but  becomes  flattened  toward  the  cervix  where 
sometimes  a  pronounced  depression  may  exist. 
The  point  of  contact  with  the  central  incisor  is 
about  one-third  the  distance  from  the  cutting  edge. 

The  Distal  Surface  (Fig.  13). — This  has  the 
same  general  outline  as  the  mesial  but  is  more 
rounded  in  every  way.     The  cervical  margin  is       fig.  14.— Right  Upper 
similar  to  that  on  the  mesial  face  but  the  labial    lateral  incisor,    Incisal 

view. 

and  lingual   are  shorter,  meeting  at  the  distal 

angle  which  is  less  sharp  and  nearer  the  gingival  margin  than  the 
mesial  angle.  The  prominence  of  this  surface  makes  this  tooth  quite 
different  from,  the  other  incisors  and  the  surface  is  more  nearly  the 
shape  of  the  mesial  surface  of  the  cuspid  with  which  it  is  in  contact. 

The  Cervical  Margin. — Although  like  the  central  in  general  char- 
acteristics, the  labial  and  lingual  portions  of  this  line  are  more  convex 
rootward,  the  latter  being  a  sharper  curve  and  extending  proportion- 
ately higher  than  the  labial.  The  mesial  and  distal  portions  are  con- 
cave rootward,  are  similar  in  general  form,  and  are  quite  angular. 

The  Incisive  Edge  (Fig.  14). — This  is  proportionately  shorter  than 
that  of  the  central,  is  often  a  nearly  straight  line  between  the  angles 
of  the  crown  and  is  usually  slightly  curved  in  a  labial  direction  as  the 
tooth,  is  viewed  from  below.  Like  the  central  incisor,  at  the  time  of 
its  eruption  it  displays  usually  three  developmental  tubercles  which 
indicate  the  three  points  at  which  calcification  begins,  but  these  are 
soon  worn  off. 

The  Root. — The  root  of  the  lateral  incisor  has  a  general  conical 
form,  is  often  slightly  longer  than  that  of  the  central  incisor,  and  is 


lO 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


flattened  mesio-distally.  Its  extremity  usually  has  a  slight  distal  bend. 
At  the  neck  of  the  tooth  it  is  almost  circular  in  cross-section  and  is 
again  at  the  apex,  but  the  intervening  portion  exhibits  the  flattening 
above  referred  to  and  in  some  instances  pronounced  grooves  upon  the 
mesial  and  distal  surfaces.  In  the  center  of  its  length  the  root  is  ap- 
proximately one-third  greater  in  labio-lingual  diameter  than  mesio- 
distally. 

The  Pulp  Cavity. — This  corresponds  in  form  to  that  of  the  tooth 
and  differs  but  little  except  in  size  from  that  of  the  central  incisor. 


Fig. 


15- 


-Right  Lower  Central  Incisor. 
Labial  Surface. 


Fig.  1 6. — Right  Lower  Central  Incisor. 

Lingual  Surface. 


THE  LOWER  CENTRAL  INCISOR. 

This  is  the  smallest  tooth  in  the  mouth.  Its  crown  is  wedge-shaped 
(Fig.  17). 

The  Labial  Surjace  (Fig.  15). — In  outline  this  face  of  the  crown  is 
nearly  triangular,  the  incisive  margin  being  the  base  while  the  mesial 
and  distal  margins  converge  to  the  rounded  apex  formed  by  the  cervical 
margin.  The  incisive  edge  is  nearly  straight  and  almost  at  right  angles 
with  the  long  axis  of  the  tooth.     The  mesial  and  distal  margins  are 


THE    LOWER    CENTRAL    INCISOR.  II 

long  curves,  the  distal  being  very  slightly  shorter  and  more  curved. 
The  cervical  border  is  very  short;  the  surface  is  convex  from  incisive 
edge  to  cervix,  and,  when  seen  in  profile,  is  almost  exactly  the  arc  of  a 
circle.  Near  the  incisive  edge  the  surface  is  nearly  straight,  the  di- 
vision between  it  and  the  mesial  distal  surfaces  being  marked  by  fairly 
well-defined  angles;  as  the  cervix  is  approached,  however,  it  becomes 


Fig.  17. — Right  Lower  Central  Incisor.         Fig.  18. — Right  Lower  Central  Incisor. 
Mesial  Surface.  Distal  Surface. 


more  rounded.  Like  the  upper  incisors  it  is  sometimes  marked  by 
two  developmental  grooves  but  these  are  normally  poorly  discernible 
except  in  young  teeth. 

The  Lingual  Surface  (Fig.  16). — Like  the  labial  surface  this  is 
nearly  triangular  in  outline  but  the  rounded  apex  formed  by  the  cervical 
margin  is  more  nearly  an  acute  angle.  The  surface  is  concave  from 
incisive  margin  to  the  cervical  ridge  when  this  latter  causes  it  to  be 
marked  with  a  convexity  which  ends  abruptly  by  a  well-defined  margin 
at  the  neck  of  the  tooth.  The  mesial  and  distal  marginal  ridges  are 
usually  poorly  defined,  the  cervical  ridge  in  which  they  unite  corre- 
sponding with  them  in  this  particular  except  that  it  is  usually  somewhat 


12 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


Fig.  19. — Right  Lower 
Central  Incisor.  Incisal 
View. 


more  easily  traced.     The  incisal  third  of  this  surface  is  usually  slightly 

bowed  in  a  labial  direction,  making  it  concave  mesio-distally,  but  this 
concavity  gradually  disappears  before  the  center 
of  the  surface  is  reached. 

The  Mesial  Surface  (Fig.  17). — This  is  tri- 
angular in  outline,  but  unlike  the  labial  and 
lingual  surfaces  the  base  of  the  triangle  is 
directed  rootward  and  is  formed  by  a  concave 
cervical  margin.  The  sides  of  the  triangle 
formed  by  the  labial  and  lingual  margins  are 
curved  in  a  labial  direction,  the  labial  being 
shorter  and  more  curved  and  meeting  the  lingual 
at  the  mesial  angle  of  the  tooth.     This  surface  is 

slightly  convex,  being  most  markedly  so  at  its  center  just  above  which 

point  it  is  in  contact  with  its  fellow  of  the  opposite  side. 
The   Distal   Surface    (Fig.    18). — This   is 

similar  in  outline  and  contour  to  the  mesial 

surface,  except  that  it  is  shghtly  shorter  and  is 

more  convex  in  its  incisive  third  because  the 

labial  and  lingual  margins    meet  in  a  more 

rounded  eminence  the  distal  angle.     Near  the 

cervical  margin  it  is  often  slightly  concave,  in 

which  instance    the  concavity  is  commonly 

continued  up  the  root  as  a  longitudinal  de- 
pression. 

The  Incisive  Edge   (Figs.  15  and   19). — 

Like  those  of  the  upper  jaw  the  lower  central 

incisor  at  the  time  of  its  eruption  is  usually 

characterized  by  the  presence  of  three  tuber- 
cles upon  its  incisive  edge.     These  are  soon 

worn  off  and  the  edge  is  then  straight.      It 

occupies  a  line  at  right  angles  to  the  long  axis 

of   the  tooth,  terminating  in  the  mesial  and 

distal  angles  of  which  the  former  is  slightly 

the  more  pronounced. 

The  Cervical  Margin. — This  is  similar  in 

outline  to  that  of  the  upper  incisors  except 

that  it  is  more  angular.     On  the  mesial  and 

distal  surfaces  it  is  markedly  concave  in  the 

direction  of  the  crown  and  extends  rootward  on  the  lingual  and  the 

labial   surface.      The   lingual    portion    is  short  and   angular,  which 


Fig.  20. — Right  Lower 
Central  Incisor.  Labio- 
lingual  longitudinal  section 
showing  bifurcation  of  pulp 
canal. 


THE    LOWER    LATERAL    INCISOR.  I3 

latter  characteristic  is  caused  by  the  projection  downward  of  the 
abrupt  cervical  ridge  of  this  surface  of  the  crown.  The  labial  portion 
of  the  cervical  margin  is  convex  rootward  but  less  sharply  so  than  the 
lingual. 

The  Root. — The  root  on  this  tooth  is  more  delicate  than  that  of  any 
other  in  the  mouth.  It  is  conical  in  shape,  being  much  flattened  upon 
its  mesial  and  distal  sides  (Figs.  17  and  18)  at  the  cervix  from  which 
point  these  surfaces,  slope  in  almost  straight  lines  to  the  apex.  This 
latter  is  sometimes  slightly  deflected  in  a  distal  direction.  These  sides 
of  the  root  are  frequently  marked  with  longitudinal  grooves  which  ex- 
tend almost  to  the  apex.  The  labial  and  lingual 
aspects  of  the  root  are  narrow,  the  former  being 
the  wider  and  they  converge  gradually  to  within  a 
short  distance  of  the  apex  when  they  rapidly  ap- 
proach each  other  and  give  the  root  a  rounded  ap- 
pearance which  is  observed  when  it  is  viewed  from 
the  mesial  or  distal  side.  The  labial  surface  of  the 
root  continues  the  line  of  that  surface  of  the  crown, 
making  with  it  almost  a  perfect  arc  of  a  circle.  Lower  Cental 'in- 

The    Pulp    Cavity. — This     cavity     follows     the     cisor.  Cross-section  of 
.  crown  near  its  middle 

general  form  of  the  exterior  of  the  tooth  and  only  looking  rootward. 
a  few  points  need  to  be  touched  upon  in  its  de- 
scription. The  horns  of  the  pulp  chamber  extend  well  toward  the 
mesial  and  distal  surfaces,  but  the  cavity  is  very  narrow  labio-lingually 
at  its  extremity.  There  is  no  perceptible  line  of  division  between  this 
and  the  pulp  canal.  The  latter  is  flattened  and  narrow  in  its  beginning 
at  the  cervix  (Fig.  20)  and  occasionally  divides  into  two  canals  which 
usually  unite  near  the  apex  and  terminate  in  a  single  foramen.  In 
most  instances,  however,  it  exists  as  a  small,  slightly  flattened  canal. 

THE  LOWER  LATERAL  INCISOR. 

This  tooth  so  nearly  resembles  the  lower  central  incisor  that  sepa- 
rate description  seems  superfluous,  therefore  only  its  differentiating 
characteristics  will  be  pointed  out.  It  is  wider  mesio-distally  than 
the  lower  central  incisor;  its  distal  angle  is  more  rounded  and  its  distal 
surface  slightly  more  convex.  Its  root  is  somewhat  longer  than  that 
of  the  lower  central  incisor  and  at  its  apex  is  often  bent  distally.  The 
pulp  chamber  is  similar  in  all  respects  to  that  of  the  lower  central  in- 
cisor except  that  it  is  slightly  larger  in  its  coronal  portion  in  corre- 
spondence with  the  greater  size  of  the  crown. 


14 


THE  ANATOMY  OF  THE  HUMAN  TEETH. 


THE  UPPER  CUSPID. 

The  crown  of  this  tooth  presents  for  examination  four  surfaces  and 
a  cusp. 

The  Labial  Surface  (Fig.  22). — The  outline  of  this  surface 
shows  that  it  is  bounded  with  five  margins.  The  incisal  portion 
provides  two,  the  mesial  and  distal  incisive  edges.  The  former  of 
these  extends  from  the  point  of  the  cusp  to  the  mesial  angle, 
being   either   concave   because   of  the   presence  of   a  developmental 


Fig.  22. 


Right  Upper  Cuspid. 
Labial  Surface. 


Fig.  23. — Right  Upper  Cuspid. 
Lingual  Surface. 


groove  or  it  may  be  slightly  convex.  The  distal  incisive  margin  which 
extends  from  the  cusp  to  the  distal  angle  is  usually  longer  than  the 
mesial  incisive  and  more  frequently  marked  with  a  slight  convexity. 
The  wearing  down  of  the  cusp  in  adult  teeth  usually  results  in  making 
the  point  of  separation  between  these  margins  less  distinct.  The 
mesial  margin  of  the  labial  surface  is  convex,  as  is  also  the  distal  which 
descends  from  the  distal  angle  of  the  crown.  The  cervical  margin 
follows  very  much  the  same  curve  as  that  of  the  central  incisor,  the 
highest  portion  of  its  convexity,  however,  being  a  little  nearer  its  mesial 


THE    UPPER    CUSPID. 


15 


end.  The  surface  is  convex  from  cusp  to  cervix  and  also  from  the 
mesial  to  the  distal  angle  but  is  sometimes  marked  by  two  longitudinal 
developmental  grooves.  These,  beginning  nearer  the  mesial  and  distal 
angles  than  the  cusp  of  the  crown,  ascend  toward  the  cervix,  gradually 
disappearing  about  the  upper  third  of  the  surface.  The  labial  ridge 
ascends  from  the  cusp,  being  located  nearer  the  mesial  than  the  distal 
surface  of  the  crown,  and  gradually  blends  with  the  rounded  convexity 
of  the  upper  third  of  this  surface.     When  the  developmental  grooves 


Fig.  24. — Right  Upper  Cuspid. 
Mesial  Surface. 


Fig.  25. — Right  Upper  Cuspid. 
Distal  Surface. 


are  not  marked  the  labial  surface  mesial  to  the  ridge  is  more  convex 
than  that  distal  to  it. 

The  Lingual  Surfaee  (Fig.  23). — With  much  the  same  outline  as 
the  labial  face,  this  surface  is  slightly  smaller,  bat  is  proportionately 
longer  from  cusp  to  cervix,  and  has  a  shorter  and  more  convex  cervicd 
margin.  The  surface  has  a  general  convexity  and  is  marked  by  a 
lingual  ridge  which  ascends  from  the  cusp  and  does  not  fade  away 
until  it  reaches  the  cervical  marginal  ridge.  It  corresponds  in  posi- 
tion to  the  labial  ridge  of  the  opposite  face  of  the  crown.  In  dis- 
tinctly marked  teeth  there  is  a  groove  on  either  side  of  this  ridge. 


i6 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


Fig.  26. — Right  Upper  Cuspid 
Incisal  View. 


The  cervical  marginal  ridge  is  usually  a  pronounced,  rounded  eleva- 
tion affording  a  distinct  line  of  demarcation  between  the  crov^n  and 

root  of  this  tooth.  It  is  frequently  the  seat 
of  an  elevation  at  or  near  its  center,  and 
may  have  a  fissure  dividing  the  ridge  on 
either  or  both  sides  of  the  cingulum.  The 
mesial  and  distal  marginal  ridges  are  less 
well  marked  than  the  cervical  from  which 
they  extend  to  the  mesial  and  distal  angles 
of  the  crown.  The  mesial  is  the  longer  and 
better  defined. 

The  Mesial  Surface  (Fig.  24). — Shaped 
like  an  arrow-head,  the    labial   boundary 

convex  and  the  lingual  usually  concave,  the  outline  of  this  surface  is 

completed  by  the  concave  cervical  margin.     The  lowest  portion  of  this 

latter  is  slightly  nearer  its  junction  with  the 

labial    than  with  the  lingual  margin.      The 

mesial  angle  which  is  the  meeting  ground  of 

the  labial  and  lingual  margins  is  just  below 

the  point  at  which  this  tooth  is  in  contact  with 

the  lateral  incisor.     It  is  not  quite  so  near  the 

cervix  as  is  the  distal  angle.     The  surface  is 

nearly  convex  in  its  lower  two-thirds  but  above 

this  point  may  be  flat  or  slightly  concave. 
The    Distal   Surface    (Fig.  25). — This    is 

similar  in  shape  to  the  mesial  but  is  some- 
what  smaller   in   extent   and    more  convex. 

The  distal  angle  is  more  protuberant  than  the 

mesial  and  just  above  it  is  a  rounded  point 

with  which  the  tooth  is  in  contact  with  the 

first  bicuspid.      The  cervical  margin  is  less 

concave    than    the    mesial    and    its   highest 

portion  is  nearer  the  labial  than  the  lingual 

margin. 

The  Cusp  (Fig.  26). — This  is  the  prominent 

point  of  the  cutting  edge  and  is  formed  by  the 

union  of  the  mesial  and  distal  cutting  edges 

and  the  labial  and  lingual  ridges.     It  is  sharp 

in  well-marked  teeth  at  the  time  of  eruption 

but  the  point  is  soon  worn  down  and  may  be  blunt  or  rounded. 

The  Cervical  Margin. — Convex  labially  and  lingually  and  concave 


Fig.  27. — Right  Upper 
Cuspid.  Longitudinal  sec- 
tion cut  antero-posteriorly 
showing  pulp  cavity. 


THE    LOWER   CUSPID.  1 7 

mesially  and  distally,  this  margin  corresponds  closely  to  that  of  the 
upper  central  incisor. 

The  Root. — Like  that  of  all  single-rooted  teeth  the  root  of  the 
upper  cuspid  is  conical.  On  all  its  four  sides  it  gradually  tapers 
from  the  cervix  to  the  apex.  In  cross-section  at  the  cervical  margins 
(Fig.  28)  it  is  ovoid  or  may  be  almost  circular.  In  the  former  instance 
the  labial  side  is  the  segment  of  a  larger  circle 
than  the  lingual.  The  mesial  and  distal 
aspects  of  the  roots  are  often  flattened,  in 
which  case  their  centers  sometimes  present 
poorly  marked  longitudinal  grooves.  At  the 
apex  the  root  is  usually  inclined  in  a  distal 
direction  or  the  whole  root  may  have  a  slight 
distal  curve. 

The  Pulp  Cavity  (Figs,  27  and  28). — In 
the  young  tooth  there  is  a  pronounced  pro-  pir^ct-S^^afce™" 
jection  of  the  pulp  chamber  wall  toward  the  looking  crownward,  showing 

.     ,  .  ,       1  .,    ,  shape  of  pulp  cavity. 

cusp  of  this  tooth,  but  as  it  becomes  more 

mature  the  pulp  cavity  becomes  more  flattened  here.  Otherwise  it  is 
very  much  like  the  external  form  of  the  tooth,  extending  well  toward 
the  mesial  and  distal  angles,  and  closely  resembling  that  of  the  central 
incisor.  At  the  level  of  the  cervix  it  is  oval  in  cross-section  and  ex- 
tends gradually  diminishing  in  size  to  the  apex.  There  is  no  line  of 
demarcation  between  the  root  and  coronal  portion  of  the  cavity. 

THE  LOWER  CUSPID. 

The  crown  of  the  cuspid  of  the  lower  series  is  very  similar  to  that 
of  the  upper,  except  that  it  is  narrower,  more  delicate  and  slightly  longer, 
and  usually  not  so  well  marked. 

The  Labial  Surface. — The  markings  of  this  surface  are  not  so  pro- 
nounced as  those  of  the  upper  cuspid.  The  outline  is  less  angular 
than  that  of  the  upper,  with  the  exception  of  that  portion  formed  by 
the  mesial  and  distal  incisive  edges,  for  its  cusp  is  more  pointed  than 
that  of  the  upper  cuspid.  The  developmental  grooves  are  usually 
poorly  defined,  the  labial  ridge  being  the  most  prominent  mark- 
ing of  this  surface  and  giving  to  it  a  marked  convexity.  This  ridge, 
as  in  the  upper  cuspid,  is  located  decidedly  nearer  the  mesial  than  the 
distal  margin.  The  mesial  margin  is  more  pronounced  than  the  distal, 
the  labial  surface  meeting  the  mesial  somewhat  more  abruptly  than 
the  distal  into  which  it  passes  by  a  rounded  curve  without  definition. 


l8  THE  ANATOMY  OF  THE  HUMAN  TEETH. 

The  Lingual  Surface. — The  outline  is  more  rounded  and  the  sur- 
face markings  less  bold  than  those  of  the  upper  cuspid.  The  marginal 
ridges  are  usually  poorly  defined,  that  at  the  cervix  being  more  prom- 
inent than  the  mesial  or  distal.  The  lingual  ridge  extends  from  the 
cusp  to  the  cervix,  dividing  this  surface  and  forming  two  very  shallow 
grooves  or  fossae,  the  lingual  grooves;  but  the  surface  is  less  convex 
than  that  of  the  upper,  especially  at  the  occlusal  end,  which  is  some- 
times flat  mesio-distally. 

The  Mesial  Stir  face. — Similar  in  shape  to  that  of  the  upper,  yet 
differing  from  it  in  some  particulars,  this  surface  of  the  lower  cuspid 
possesses  the  peculiarity  of  being  almost  flat  and  being  continuous 
as  an  almost  plane  surface  with  the  root.  At  the  cervix  it  is  slightly  con- 
cave or  it  may  be  simply  flat,  but  it  assumes  a  convex  character  as  the 
mesial  angle  is  approached.  The  cervical  outline  is  much  less  concave 
rootward  than  that  of  this  face  of  the  upper  cuspid,  but  similarly  it 
extends  to  a  lower  .level  lingually  than  labially.  The  lingual  margin  is 
well  defined  but  the  labial  is  rounded. 

The  Distal  Surface. — The  convexity  characteristic  of  this  surface 
of  the  upper  cuspid  is  observed  here,  except  that  the  cervical  portion 
is  sometimes  slightly  concave.  The  surface  is  smaller  in  extent  than 
the  mesial,  a  fact  due  to  the  lower  location  of  the  distal  angle.  The 
cervical  margin  is  pronounced,  the  surface  of  the  root  usually  forming 
a  decided  angle  with  that  of  the  crown.  The  lingual  margin  is  more 
marked  than  the  labial,  but  by  comparison  both  are  less  clearly  defined 
than  those  on  the  mesial  surface. 

The  Cusp. — The  prominent  point  of  the  tooth  occupies  a  line  al- 
most in  its  long  axis.  From  it  descend  the  mesial  and  distal  incisal 
edges  of  which  the  latter  is  slightly  longer,  but  the  difference  is  not  so 
marked  as  in  the  upper  cuspid. 

The  Cervical  Margin. — This  is  concave  in  the  direction  of  the  root 
on  the  labial  and  lingual  sides  and  convex  on  the  mesial  and  distal. 
On  the  lingual  and  distal  sides  the  root  and  crown  join  more  abruptly 
than  on  the  mesial  and  labial. 

The  Root. — The  root  is  shorter  than  that  of  the  upper  cuspid  and 
is  flattened  on  its  mesial  and  distal  sides.  Viewed  in  profile  from 
any  of  the  four  surfaces  its  sides  slope  gradually  to  the  apex  which  is 
frequently  inclined  to  the  distal. 

The  Pulp  Cavity. — This  resembles  that  of  the  upper  cuspid  except 
that  it  is  narrower  mesio-distally,  a  difference  in  form  likewise  ob- 
servable in  the  crowns  of  the  two  teeth.  It  has  no  horns  of  the  pulp 
chamber  but  terminates  in  a  pointed  extremity  beneath  the  cusp. 


THE    UPPER    FIRST    BICUSPID.  1 9 

The  pulp  canal  is  flattened  mesio-distally  at  the  cervix  but  becomes 
circular  in  its  apical  portion. 

THE  UPPER  FIRST  BICUSPID. 

The  crown  of  this  tooth  presents  for  examination  five  surfaces, 
namely,  occlusal,  buccal,  lingual,  mesial  and  distal.  It  is  irregularly 
cuboidal  in  shape. 

The  Occlusal  Surface  (Fig.  29). — When  vievv^ed  from  the  occlusal 
surface  the  crown  appears  ovoid  in  outline,  whereas  the  occlusal 
surface  proper  is  trapezoidal,  the  oval  appearance  being  due  to 
the  projection  of  the  buccal  and  lingual 
faces  of  the  tooth.  The  most  prominent 
features  of  this  surface  are  the  two  cusps  sur- 
mounting its  buccal  and  lingual  portions,  the 
buccal  and  lingual  cusps,  which  are  separated 
by  the  central  groove  and  which  give  to  the 
tooth  its  distinguishing  character  (bicuspid). 
The  margins  are  formed  by  the  buccal  cusp 
with  its  descending  mesial  and  distal  inclines, 
the  mesial  and  distal  marginal  ridges,  which 

,,jj;j.j  r  !•••        4.U  Fig.  20. — Left  Upper  First 

are  well-defined  ridges  of  enamel  jommg  the    Bicuspid.   Occlusal  Surface, 
ridges  of  the  buccal  cusp  at  the  mesial  and 

distal  angles  of  the  crown  and  converge  to  join  descending  ridges  from 
the  lingual  cusp  and  the  lingual  cusp  itself. 

The  buccal  cusp  is  the  larger,  sharper  and  more  prominent.  From 
its  summit  four  ridges  descend;  the  buccal  ridge,  which  is  partly 
responsible  for  the  prominence  of  the  buccal  surface  of  the  crown; 
the  triangular  ridge,  which  extends  downward  toward  the  central  groove 
and  usually  terminates  there;  and  one  each  mesially  and  distally  to 
reach  the  mesial  and  distal  angles  respectively.  Of  these  latter  two, 
the  distal  is  usually  the  larger  and  the  more  inclined,  the  point  of  the 
cusp  being  usually  nearer  the  mesial  than  the  distal  face  of  the  crown. 

The  lingual  cusp  is  lower  and  much  more  rounded  than  the  buccal 
and  the  three  ridges  descending  trom  it  are  less  pronounced.  The 
triangular  ridge  is  often  missing  but  when  present  it  descends  toward 
the  central  groove  to  meet  the  ridge  from  the  buccal  cusp.  Occasion- 
ally these  two  triangular  ridges  unite  and  form  the  transverse  ridge, 
but  usually  they  are  separated  by  a  fissure  in  the  central  groove.  The 
ridges  descending  mesially  and  disially  from  this  cusp  join  and  are 
continuous  with  the  marginal  ridges,  being  curved  so  that  the  lingual 
outline  of  the  occlusal  surface  is  much  rounded.     The  lingual  aspect 


20 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


of  the  lingual  cusp  is  convex  and  rounded  and  gradually  blends  with  the 
lingual  surface. 

The  mesio-distal  groove  separates  the  cusps  and  extends  from  the 
mesial  to  the  distal  marginal  ridges.  It  is  sometimes  extended  at  each 
extremity  into  the  mesial  and  distal  developmental  grooves  which 
when  present  are  fine  lines  crossing  the  marginal  ridges  to  reach  the 
mesial  and  distal  surfaces  of  the  crown.  The  triangular  grooves  are 
short,  cross  the  central  groove  at  its  terminations  at  right  angles,  ex- 


FlG. 


3°- 


-Left  Upper  First  Bicuspid. 
Buccal  Surface. 


Fig.  31. — Left  Upper  First  Bicuspid. 
Lingual  Surface. 


tend  toward  the  angles  of  the  crown,  and  separate  the  mesial  and 
distal  marginal  ridges  from  the  triangular  ridges.  The  junctions  of 
these  grooves  with  the  central  groove  are  often  spoken  of  as  the  mesial 
and  distal  pits. 

The  Buccal  Surface  (Fig.  30). — This  closely  resembles  in  form 
and  outline  the  labial  surface  of  the  cuspid  tooth,  being  smaller  and 
more  compressed  occluso-gingivally.  It  is  bounded  by  four  margins, 
the  occlusal,  the  cervical,  the  mesial  and  the  distal.  The  occlusal  is 
formed  by  the  mesial  and  distal  inclines  of  the  buccal  cusp  and  is  well 
defined.    The  mesial  incline  is  usually  a  straight  line  or  is  slightly  convex, 


THE    UPPER    FIRST    BICUSPID, 


21 


while  the  distal  may  be  marked  with  a  concavity  caused  by  the  distal  buc- 
cal groove.  The  mesial  border  is  more  sharply  defined  than  the  distal. 
It  descends  from  the  mesial  angle  to  the  cervical  border,  which  latter  is 
nearly  straight  or  may  be  slightly  convex  rootward  and  is  not  distinctly 
marked  by  an  abrupt  termination  of  the  enamel.  The  distal  margin 
is  usually  shorter  and  more  rounded  than  the  mesial,  because  of  the 
lower  position  of  the  distal  angle,  and  the  fact  that  the  buccal  surface 
rounds  into  the  distal  without  a  sharp  line  of  definition.    The  buccal 


Fig.  32. — Left  Upper  First  Bicuspid. 
Mesial  Surface. 


Fig.  33. 


-Left  Upper  First  Bicuspid. 
Distal  Surface. 


ridge,  descending  from  the  buccal  cusp  and  flanked  by  the  buccal 
developmental  grooves,  which  are  forced  well  towards  the  angles  of 
the  crown,  contributes  towards  the  convexity  of  this  surface.  It 
usually  disappears  by  blending  with  this  convexity  about  the  center 
of  the  surface,  but  occasionally  in  well-marked  teeth  it  extends  almost 
to  the  cervical  margin.  The  greater  mesio-distal  diameter  of  the  crown 
at  the  level  of  the  angles  than  at  the  cervical  margin  gives  to  the  crown 
its  characteristic  bell-shape,  which  may  be  well  observed  when  looking 
at  it  from  the  buccal  side. 

The  Lingual  Surface   (Fig.  31). — This  face  is  smaller  than  the 
buccal,  being  both  shorter  and  narrower.     It  is  convex  mesio-distally 


22 


THE  ANATOMY  OF  THE  HUMAN  TEETH. 


and  rounds  into  the  mesial  and  distal  face  without  line  of  demarca- 
tion. Its  occlusal  margin  is  also  rounded,  being  formed  by  the  lingual 
cusp  and  the  ridges  descending  from  it,  while  the  gingival  margin  is 
either  nearly  straight  or  is  only  slightly  convex  rootward.  The  sur- 
face is  curved  from  the  summit  of  the  lingual  cusp,  which  is  slightly 
nearer  the  mesial  face  of  the  crown,  to  the  cervix,  its  outline  when 
seen  in  profile  being  a  long  gentle  curve.  It  is  usually  quite  smooth 
and  without  grooves. 

The  Mesial  Surface  (Fig.  32). — Ir- 
regularly quadrilateral  in  shape,  this 
face  of  the  crown  is  bordered  occlusally 
by  the  mesial  marginal  ridge  and  a 
portion  of  the  ridge  from  the  lingual 
cusp,  and  gingivally  by  the  cervical 
line  which  is  usually  nearly  straight  or 
slightly  concave  in  the  direction  of  thei 
root.  The  occlusal  margin  is  concave, 
the  concavity  being  about  midway  be- 
tween the  cusps.  Frequently  this 
margin  is  broken  by  the  mesial  de- 
velopmental groove  which  reaches  this 
face  from  the  occlusal  surface  and 
usually  terminates  about  its  center. 
The  buccal  margin  is  fairly  well  de- 
fined and  extends  from  the  mesial 
angle  to  the  cervix,  while  the  lingual  is 
so  rounded  by  the  gradual  joining  of 
the  lingual  surface  as  to  be  indistin- 
guishable. Near  the  occlusal  margin 
the  surface  is  full  and  rounded,  giving  a  point  of  contact  for  the 
proximal  side  of  the  cuspid,  but  it  flattens  out  as  the  cervix  is  ap- 
proached and  in  this  location  is  usually  the  seat  of  a  depression 
which  is  continued  up  the  face  of  the  root. 

The  Distal  Surface  (Fig.  33). — While  this  is  much  like  the  mesial 
surface,  it  is  smaller  in  extent  and  more  convex.  The  buccal  margin 
is  not  so  pronounced  as  that  of  the  mesial  face  and  is  usually  shorter. 
The  cervical,  lingual  and  occlusal  margins  are  very  much  like  those 
of  the  mesial  fac  ■  and  the  lingual  is  poorly  defined  and  much  rounded. 
In  its  occlusal  third  the  surface  is  quite  convex  in  all  directions  and 
this  usually  extends  in  decreasing  degree  to  the  cervix,  although  the 
corresponding  portion  of  the  mesial  face  is  usually  concave  bucco- 


FiG.  34. — Left  Upper  First  Bicuspid. 
Bucco-lingual  longitudinal  section, 
showing  pulp  chamber,  its  horns,  and 
the  pulp  canals. 


THE    UPPER    FIRST    BICUSPID.  23 

lingually.  The  distal  developmental  groove  sometimes  crosses  the 
upper  margin  from  the  occlusal  surface  and  disappears  about  the 
center  of  the  surface. 

The  Cervical  Margin. — This  is  more  nearly  straight  around  the 
tooth  than  that  of  any  of  the  teeth  so  far  described,  usually  having, 
however,  a  slight  curve  rootward  on  both  buccal  and  lingual  surfaces 
and  being  curved  toward  the  occlusal  surface  on  the  mesial  and  distal 
faces. 

The  Root. — The  upper  first  bicuspid  usually  has  two  roots  (Fig.  32) 
or  two  branches  of  its  root,  which  are  located  beneath  its  two  cusps  and 
are  called  the  buccal  and  lingual  roots.  Occasionally  the  tooth  has  only 
one  root,  or  the  division  may  occur  very  near  its  apex.  In  the  former 
instance  the  central  portion  of  the  root  between 
the  two  pulp  canals  is  thin  and  usually  consists 
only  of  cementum.  The  occurrence  of  two 
separated  roots  is  most  frequently  noted  and  in 
this  instance  the  roots  are  delicate  and  taper 
gradually  to  a  somewhat  sharp  apical  extremity 
and  are  usually  curved  in  several  directions. 
These  curves  are  usually  first  in  a  buccal  and 
lingual  direction,  serving  to  separate  the  roots 
which  again  approach  each  other  at  their  termi-       .^  .  ,    ,. 

.  .  Fig.   35. — Left    Upper 

nations.  There  is  often  a  gentle  distal  curve  in  First  Bicuspid.  Cross- 
both  roots.  The  bifurcation  is  usually  located  rhoSlTapr ""S 
about  one-third  the  distance  from  the  cervix,  and  canal, 
is  accomplished  by  a  meeting  of  the  groove  noted  on  the  mesial  face 
of  the  root  and  originating  in  the  crown,  with  one  which  develops 
above  the  cervix  on  the  distal  side  of  the  root. 

The  Pulp  Cavity. — The  pulp  chamber  and  the  pulp  canal  are 
usually  diflferentiated  in  this  tooth  (Fig.  34),  the  chamber  correspond- 
ing to  the  general  shape  of  the  crown,  the  canals  to  the  form  of  the 
roots.  The  chamber  is  a  cavity  with  flattened  mesial  and  distal  walls 
and  curved  buccal  and  lingual  walls.  In  the  mature  tooth  these  latter 
are  nearly  parallel  and  terminate  occlusally  in  the  buccal  and  lingual 
horns  of  the  pulp  chamber,  which  are  cone-shaped  projections  of  the 
cavity  penetrating  the  two  cusps.  The  occlusal  wall  of  the  chamber 
is  marked  by  a  projection  corresponding  to  the  central  groove  of  the 
occlusal  surface  of  the  crown.  In  horizontal  cross-section  at  this 
level,  the  cavity  is  larger  than  at  the  cervix,  the  mesial  and  distal  walls 
converging  to  this  point  in  correspondence  with  the  external  surface  of 
the  crown. 


24  THE  ANATOMY  OF  THE  HUMAN  TEETH. 

The  floor  of  the  pulp  chamber,  which  is  usually  about  on  a  leveJ 
with  the  cervix,  differs  in  character  in  accordance  with  the  root  forma- 
tion of  the  tooth.  In  teeth  with  two  roots  or  in  those  with  two  root 
canals,  the  buccal  and  lingual  walls  of  the  chamber  are  continued  as 
the  corresponding  walls  of  the  two  pulp  canals,  but  in  old  teeth  a  line  of 
definition  between  the  two  is  caused  by  an  inward  projection  of  the  wall. 
The  openings  to  the  two  canals  are  funnel-shaped  and  are  separated 
by  a  ridge  corresponding  to  the  root  bifurcation.  The  canals  are 
usually  about  circular  in  cross-section,  and  follow  the  directions  of  the 
roots,  occupying  their  centers.  When  the  tooth  has  only  one  root, 
it  sometimes  has  only  one  pulp  canal  (Fig.  35),  which  is  flat  and  ribbon- 
like in  its  gingival  portion,  becoming  more  nearly  round  as  the  apex  is 
reached.  Often  in  single-rooted  teeth  there  are  two  pulp  canals, 
which  either  terminate  in  separate  foramina  close  together  or  coalesce 
just  before  reaching  the  apex,  a  single  canal  making  exit  at  the  apex» 

THE  UPPER  SECOND  BICUSPID. 

This  tooth  so  closely  resembles  the  upper  first  bicuspid  that  it  will 
only  be  necessary  to  point  out  the  differences  between  the  two.  The 
crown  of  the  tooth  is  smaller  and  its  prominences  are  more  rounded 
than  those  of  the  first  bicuspid.     It  is  always  shorter  from  cusps  ta 

cervix  but  the  bucco-lingual  diameter  at 
the  cervix  is  sometimes  slightly  greater  than 
that  of  the  first.  On  the  occlusal  surface 
(Fig.  36)  both  cusps  are  more  rounded, 
and,  unlike  the  first  bicuspid,  are  usually 
of  equal  length.  The  lingual  cusp  is  usually 
equal  in  size  to  that  of  the  first  bicuspid 
while  the  buccal  is  smaller,  in  consequence 
of  which  facts  the  two  cusps  of  this  tooth 
are  approximately  equal  in  size.  The  tri- 
^       ^     _.  ,  ,    angular  ridges  usually  unite  to  form  a  trans- 

FiG.  36.— Right  Upper  Second  &  &  -^  ,       ,  , 

Bicuspid.    Occlusal  Surface.        verse  ridge,  the  central  groove  is  shortened 

mesio-distally,  and  usually  terminates  in 
pits  instead  of  well-marked  triangular  grooves.  The  buccal  (Fig.  37) 
and  lingual  (Fig.  t,S)  faces  of  the  crown  are  smaller  and  more  rounded 
than  those  of  the  first  bicuspid,  the  mesial  (Fig.  39)  and  distal  (Fig.  40) 
faces  being  similar  to  those  of  the  first  except  that  the  concavity  on  its 
mesial  face  near  the  cervical  margin  is  missing.  This  is  one  of  the  chief 
distinguishing  features  of  the  tooth.  The  cervical  margin  more  nearly 
occupies  a  horizontal  plane  than  that  of  the  first  bicuspid,  being. 


THE    UPPER    SECOND    BICUSPID. 


25 


Fig.  37. — Right  Upper  Second  Bicuspid.      Fig.  38.^Right  Upper  Second  Bicuspid. 
Buccal  Surface.  Lingual  Surface. 


Fig.  39. — Right  Upper  Second  Bicuspid.      Fig.  40. — Right  Upper  Second  Bicuspid. 
Mesial  Surface.  Distal  Surface. 


26 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


slightly  curved  rootward  on  buccal  and  lingual  surfaces  and  being 
almost  straight  on  the  mesial  and  distal  sides.     A  single  root  is  char- 


f  10.  41. — Right  Upper  Second  Bicuspid 
Bucco-lingual  longitudinal  section,  showing^ 
pulp  cavity. 


Fig.  42. — Right  Upper  Second  Bicuspid. 
Mesio-distal  longitudinal  section,  looking 
buccally.     Showing  pulp  cavity. 


acteristic  of  this  tooth.  It  is  much  flattened  on  its  mesial  and  distal 
sides  and  is  usually  marked  with  a  longitudinal  groove  on  each  of 
these  surfaces.  Its  extremity  is  usually  rounded 
and  occasionally  bifid.  Its  buccal  and  lingual 
surfaces  converge  much  more  in  reaching  the 
apex  than  do  its  mesial  and  distal.  The  root 
sometimes  has  a  curve  in  a  distal  direction  near 
its  termination. 

Inasmuch  as  this  tooth  normally  has  but  one 
root,  the  pulp  cavity  consists  of  a  pulp  chamber 
corresponding  in  shape  to  that  of  the  crown  and 
a  single  pulp  canal  (Fig.  41).  While  the  pulp 
chamber  is  similar  in  form  to  that  of  the  first 
bicuspid,  the  horns  of  the  chamber  are  less 
pointed  and  penetrating,  because  of  the  dififer- 
ences  in  the  cusps  of  these  two  teeth.  The  pulp  canal  has  its  walls 
continuous  v/ith  those  of  the  chamber,  no  definite  demarcation  be- 


j  Fig.  43. — Right  Upper 
Second  Bicuspid.  Cross- 
section  of  root  above  cer- 
vix, showing  pulp  canal. 


THE    LOWER    FIRST   BICUSPID.  27 

tween  the  two  existing.  It  is  narrow  mesio-distally  and  ribbon-like 
at  the  cervix  but  is  usually  easy  to  enter  (Fig.  43).  Occasionally  this 
tooth  has  two  roots,  in  which  case  two  root  canals  can  be  found,  and 
their  existence  should  be  considered  among  the  rare  possibilities  in  the 
treatment  of  these  teeth. 


THE  LOWER  FIRST  BICUSPID. 

While  partaking  of  the  characteristics  of  the  upper  bicuspid  teeth, 
the  lower  first  bicuspid  departs  from  the  typical  bicuspid  design  in  the 
rudimentary  development  of  its  lingual  cusp.  The  great  variation  in 
the  development  of  this  cusp  accounts  for  the  variations  in  form  so 
commonly  observed  in  this  tooth. 

The  Occlusal  Surface  (Fig.  44). — Viewed  from  the  occlusal  surface 
the  outline  of  the  crown  appears  almost  circular  or  ovoid  but  this  is 
due  to  the  fact  that  the  upper  portion  of  the  bulging  buccal  face  is 
visible.  The  surface  presents  for  examination  a  buccal  cusp,  either  a 
lingual  cusp  or  a  lingual  ridge,  a  mesial  and 
distal  pit  and  marginal  ridges  bordering  the 
surface.  The  summit  of  the  buccal  cusp  is 
nearly  in  the  line  of  the  long  axis  of  the  crown. 
Four  ridges  descend  from  it,  one  each  in  a 
buccal,  lingual,  mesial  and  distal  direction. 
The  two  latter  unite  at  the  mesial  and  distal 
angles  with  the  marginal  ridges.  The  buccal 
extends  upon  the  buccal  face  of  the  crown  and 

...  Till-  Fig.  44. — Left  Lower  First 

the  Imgual  is   more  strongly  developed,  is  not     Bicuspid.     Occlusal  Surface. 

crossed  by  a  groove,  reaches  the  lingual  ridge 

or  lingual  cusp,  and  separates  the  mesial  and  distal  pits.  The  mesial 
and  distal  marginal  ridges  converge  to  unite  and  form  a  semicircle 
with  a  lingual  prominence  of  enamel,  which  when  much  elevated 
above  the  adjoining  margin  ridges  is  considered  the  lingual  cusp  and 
when  only  existing  as  a  ridge  is  called  the  lingual  marginal  ridge. 

The  Buccal  Surface  (F  g.  45). — This  corresponds  so  closely  to  that 
of  an  upper  bicuspid  that  detailed  description  would  be  superfluous. 
The  cusp  is  not  so  pointed,  the  buccal  developmental  grooves  are 
poorly  developed,  the  crown  is  shorter  and  narrower  than  its  fellow 
of  the  upper  series,  the  cervical  line  is  almost  straight,  and  the  surface 
is  convex  and  slopes  inward  to  the  summit  of  the  buccal  cusp  which  is 
usually  in  line  with  the  long  axis  of  the  root. 

The  Lingual  Surface  (Fig.  46). — This  is  small  because  of  the  small 


28 


THE  ANATOMY  OF  THE  HUMAN  TEETH. 


Fig.  45. — Left  Lower  First  Bicuspid. 
Buccal  Surface. 


Fig.  46. — Left  Lower  Fir.st  Bicuspid. 
Lingual  Surface. 


Fig  47. — Left  Lower  First  Bicuspid. 
Mesial  Surface. 


Fig.  48. — Left  Lower  First  Bicuspid. 
Distal  Surface. 


THE    LOWER    FIRST    BICUSPID. 


29 


size  and  low  position  of  the  lingual  cusp.  The  occlusal  margin  is  well 
defined  and  the  surface  is  nearly  straight  from  this  point  to  the  cervix 
and  in  many  instances  is  continued  without  marked  division  into  the 
surface  of  the  root  or  it  may  make  an  obtuse  angle  with  this  face  of  the 
root.  Mesio-distally  it  is  much  rounded  passing  into  the  proximal 
surfaces  with  a  gentle  curve. 

The  Mesial  Surface  ' {Fig.  47). — Irregularly  quadrilateral  in  out- 
line, with  only  its  occlusal  margin  well  defined  by  the  marginal  ridge, 


Fig.  49. — Right  Lower  First  Bicuspid. 
Mesio-distal  longitudinal  section,  showing 
pulp  cavity. 


Fig.  50. — Right  Lower  First  Bicuspid- 
Bucco-lingual  longitudinal  section,  show, 
ing  pulp  cavity. 


this  surface  is  generally  convex.  The  most  prominent  point  of  the 
convexity  is  located  centrally  just  below  the  occlusal  margin  from  which 
the  surface  inclines  inward  toward  the  central  axis  of  the  tooth,  con- 
tributing thereby  to  give  the  bell-shape  which  is  observed  of  this  crown 
as  it  is  viewed  from  the  buccal  or  lingual  side.  At  the  cervix  the  surface 
is  flattened. 

The  Distal  Surface  (Fig.  48). — This  is  almost  similar  to  the  mesial 
except  that  its  convexity  is  usually  less  pronounced. 

The  Cervical  Margin. — The  juncture  between  enamel  and  cemen- 
tum  in  this  tooth  occupies  nearly  a  horizontal  plane,  being  continued 


30  THE  ANATOMY  OF  THE  HUMAN  TEETH. 

around  the  tooth  in  almost  a  straight  line.  There  is  frequently  a  dip 
rootward  on  the  buccal  face. 

The  Root. — A  single  root  normally  characterizes  the  lower 
first  bicuspid  although  in  rare  instances  two  roots  are  found.  When 
single  it  is  conical,  the  buccal  and  lingual  sides  being  uniformly  in- 
clined toward  each  other  and  continuing  these  faces  of  the  crown. 
The  lingual  is  the  narrower,  which  is  caused  by  the  fact  that  the  flat- 
tened mesial  and  distal  faces  converge  in  passing 
lingually.  These  latter  are  usually  slightly  con- 
vex and  uniformly  taper  to  the  apex,  but  occa- 
sionally they  are  marked  with  a  shallow  longi- 
tudinal depression.  The  end  of  the  root  is 
sharply  pointed  and  is  frequently  deflected  dis- 
tally.  The  cervical  portion  of  the  root  is  oval 
in  cross-section. 
^/'^'^- 5?--Ri|ht  Lower         jj^^  p^ip  Cavity.— As  in  all  single  rooted 

First     Bicuspid.      Cross-  ^^  -^  ... 

section  at  cervix  showing  teeth  there  is  no  sharp  _  division  between  the 
pu  p  cana  .  ^^^^  chamber  and  canal  (Fig.  49).     The  cham- 

ber has  one  well-defined  horn  situated  beneath  the  buccal  cusp  and 
when  a  lingual  cusp  exists  there  is  a  small  projection  of  the  cavity  in 
its  direction  (Fig.  50).  At  the  level  of  the  gingival  margin  the 
cavity  is  oval  in  cross-section  whence  it  continues  diminishing  in  bucco- 
lingual  diameter  to  the  apical  foramen  (Fig.  51).  It  is  usually  small 
and  thread-like  in  the  apical  third  of  the  root. 

THE  LOWER  SECOND  BICUSPID. 

While  this  tooth  bears  a  close  resemblance  to  the  lower  first  bicus- 
pid tooth  in  many  particulars,  in  some  details  it  is  quite  different. 
These  latter  chiefly  pertain  to  the  lingual  portion  of  the  occlusal  face 
of  the  crown  and  the  adjacent  surfaces  to  which  this  is  related.  In 
general  the  crown  of  the  tooth  is  smaller  and  more  rounded  than 
the  first.  Viewed  from  the  occlusal  face  it  will  be  seen  that  this 
surface  is  larger  and  even  more  nearly  circular  in  outline  than  the 
first.  In  some  instances  this  is  due  to  the  presence  of  a  well-developed 
lingual  cusp  and  prominent  marginal  ridges  mesially  and  distally. 
In  other  instances  the  same  rounded  outline  is  caused  by  the  presence 
of  two  lingual  cusps,  a  fissure  dividing  the  lingual  portion  in  its  center. 
The  buccal  cusp  is  less  prominent  than  that  of  the  first  bicuspid,  and 
has  a  well-defined  triangular  ridge  which  seldom  unites  with  that  of 
the  lingual  cusp.     When  present  the  lingual  cusp  is  smaller  than  and 


THE    UPPER    FIRST    MOLAR.  3 1 

not  so  prominent  as  the  buccal  and  is  usually  separated  from  it  by  a 
mesio-distal  groove.  This  latter  terminates  in  pits,  the  mesial  and 
distal  pits,  and  is  curved  lingually.  When  the  face  presents  three 
cusps  the  groove  has  three  branches  meeting  in  a  central  pit  or  fossa. 
The  angles  of  the  crown  are  not  well  marked. 

The  buccal  surface  is  more  rounded  and  shorter  and  wider  than  that 
of  the  first  bicuspid.  The  lingual  surface  is  proportionally  larger  than 
the  lingual  of  the  lower  first  bicuspid,  being  longer  occluso-gingivally 
because  of  the  lingual  cusp  at  the  base  of  which  it  is  also  wider 
mesio-distally.  The  mesial  and  distal  faces  of  the  crown  are 
similar  to  those  of  the  first  bicuspid  except  that  they  are  wider  bucco- 
lingually  and  are  both  slightly  more  convex.  The  cervical  margin 
encircles  the  tooth  almost  in  a  horizontal  plane,  but  a  curve  rootward 
may  usually  be  made  out  on  the  buccal  face.  The  single  root  is  con- 
ical, proportionately  longer  than  that  of  the  first  bicuspid,  flattened  on 
its  mesial  and  distal  sides,  and  usually  bent  distally  in  its  lower  portion. 
The  pulp  cavity  is  larger  than  that  of  the  first  bicuspid,  the  chamber 
being  shaped  to  correspond  with  the  external  surface  of  the  crown  and 
having  the  rudimentary  lingual  horn  better  developed.  The  canal  is 
oval  or  circular  in  cross-section  at  the  cervix  from  whence  it  tapers 
gradually  to  the  apical  foramen. 

THE  UPPER  FIRST  MOLAR. 

The  crown  of  the  upper  first  molar  is  roughly  cuboidal  in  shape  and 
offers  for  examination  five  surfaces — occlusal,  buccal,  lingual,  mesial 
and  distal. 

The  Occlusal  Surface  (Fig.  52). — This  is  irregularly  rhomboidal  in 
outline  as  may  be  seen  when  the  crown  is  viewed  from  this  surface. 
The  mesial  and  distal  margins  are  nearly  straight  and  parallel;  the 
buccal  and  lingual  margins  are  curved.  At  the  mesio-buccal  and 
disto-lingual  juncture  of  these  margins  acute  angles  are  formed  while 
the  angles  at  the  disto-buccal  and  mesio-lingual  juncture  are  obtuse. 
The  surface  is  marked  by  the  presence  of  four  cusps,  four  marginal 
ridges,  two  fossae,  and  several  developmental  grooves.  The  mesial 
marginal  ridge  is  a  rounded  and  well-defined  elevation  of  enamel 
extending  from  the  summit  of  the  mesio-buccal  cusp  to  that  of  the  mesio- 
lingual  cusp,  and  is  curved  rootward  between  these  points.  It  is  often 
crossed  near  its  center  by  the  mesial  developmental  groove  which  ex- 
tends from  the  occlusal  to  the  mesial  surface.  The  buccal  marginal 
ridge  unites  with  the  mesial  at  the  mesio-buccal  angle  of  the  tooth.     It 


32 


THE  ANATOMY  OF  THE  HUMAN  TEETH. 


extends  from  this  point  to  the  point  of  the  mesio-buccal  cusp,  then 
in  a  slightly  lingual  direction  to  the  bottom  of  the  buccal  groove,  then 
buccally  to  the  point  of  the  disto-buccal  cusp  and  then  to  the  disto- 
buccal  angle,  being  curved  latterly  in  a  lingual  direction  to  unite  with 
the  distal  marginal  ridge.  It  is  the  sharpest  of  the  marginal  ridges, 
a  fact  in  large  part  due  to  the  sharpness  of  the  buccal  cusps. 

The  distal  marginal  ridge  is  similar  to  the  mesial  in  that  it  is  curved 
rootward  between  its  terminations  and  is  a  rounded  ridge  of  enamel. 
It  is  marked  to  the  buccal  side  of  its  center  by  the  distal  groove,  which 
passes  over  upon  the  distal  face  of  the  crown.  The  lingual  termina- 
tion is  well  rounded  and  consequently 
less  easily  differentiated  from  the  disto- 
lingual  cusp  in  which  it  terminates.  The 
lingual  marginal  ridge  completes  the 
periphery  of  the  occlusal  surface,  ex- 
tending from  the  disto-lingual  to  the 
mesio-lingual  angle  of  the  crown.  From 
its  mesial  end  it  curves  lingually  to  the 
summit  of  the  mesio-lingual  cusp,  then 
buccally  to  the  point  where  it  is  divided 
by  the  disto-lingual  cusp  and  then 
lingually  again  to  the  top  of  the  disto- 
lingual  cusp.  It  is  the  most  rounded 
of  the  marginal  ridges. 

The  Cusps. — The  upper  first  molar 
may  be  said  to  possess  four  cusps  nor- 
mally but  in  a  large  number  of  cases  it  has  five.  The  mesio-buccal 
cusp,  located  near  the  mesio-buccal  angle  of  the  tooth,  is  sharp  and 
from  its  summit  descend  four  ridges.  These  latter  are  the  buccal, 
which  continues  upon  the  buccal  surface  of  the  crown,  the  triangular 
which  descends  into  the  central  fossa,  and  the  two  ridges  descending 
mesially  and  distally  forming  portions  of  the  buccal  marginal  ridge. 
The  disto-buccal  cusp  is  somewhat  smaller  than  the  one  just  described, 
but  like  it  is  sharp  and  has  four  ridges  descending  from  its  point.  The 
buccal  ridge  descends  upon  the  buccal  face,  the  mesial  and  distal 
ridges  are  portions  of  the  buccal  marginal,  while  the  fourth  ridge  unites 
with  one  from  the  mesio-lingual  cusp  to  form  the  oblique  ridge.  The 
disto-lingual  cusp  is  usually  the  smallest  (except  the  fifth)  and  is 
rounded.  But  two  ridges  descend  from  it,  one  each  in  a  mesial  and 
lingual  direction  to  form  the  marginal  ridge  of  these  boundaries.  Its 
lingual  and  distal  aspects  fade  off  into  these  respective  faces  of  the 


Fig.  52. — Left  Upper  First  Molar 
Occlusal  Surface. 


THE    UPPER    FIRST    MOLAR. 


33 


crown  without  demarcation.  It  is  separated  from  the  obhque  ridge 
by  the  disto-lingual  groove.  The  mesio-lingual  cusp  is  frequently 
the  largest  cusp  of  this  tooth.  It  is  much  rounded  and  has  ridges 
descending  from  it  as  follows:  one  to  the  mesial  to  join  the  mesial  mar- 
ginal ridge  and  one  distally  forming  a  portion  of  the  lingual  marginal 
ridge,  while  one  passes  in  the  direction  of  the  disto-buccal  cusp,  meet- 
ing a  ridge  from  the  latter  to  form  the  oblique  ridge.     The  buccal 


Fig.  53. 


—Left  Upper  First  Molar. 
Buccal  Surface. 


Fig.  54. — Left  Upper  First  Molar. 
Lingual  Surface. 


aspect  of  the  cusp  forms  a  wall  of  the  central  fossa,  while  the  lingual 
side  is  rounded  and  descends  without  demarcation  into  the  lingual 
surface  of  the  crown,  or  in  teeth  with  a  fifth  cusp  descends  into  the 
groove  dividing  the  latter  from  the  crown.  The  fifth  cusp,  or  lingual 
cingule  as  it  is  sometimes  called,  varies  much  in  size  and  occurrence. 
When  present  it  is  an  elevation  of  enamel  on  the  lingual  surface  of  the 
crown,  near  and  just  distal  to  the  mesio-lingual  angle  and  at  the  lingual 
base  of  the  mesio-lingual  cusp,  from  which  it  is  separated  by  a  groove, 
the  mesio-lingual. 

The  FosscB  and  Grooves. — The  central  fossa  is  triangular  in  shape 
and  occupies  the  space  between  the  mesio-buccal,  disto-buccal  and 
mesio-lingual  cusps,  its  walls  being  formed  by.  the  central  inclines  of 
3 


34 


THE    ANATOMY    OF    THE    HUMAN   TEETH. 


these  cusps  and  the  mesial  marginal  ridge.  In  its  center  is  the  central 
pit  from  which  radiate  the  mesial  developmental  groove,  which  passes 
forward  over  the  mesial  marginal  ridge  to  the  mesial  face  of  the  crown, 
the  buccal  groove  which  divides  the  mesio-buccal  from  the  disto-buccal 
cusp  and  reaches  the  buccal  surface  of  the  crown,  and  the  distal  which 
is  less  well  marked  and  passes  distally  over  the  oblique  ridge.  Each 
of  these  grooves  may  be  the  seat  of  a  fault  or  fissure,  the  buccal 
exhibiting  it  more  commonly  and  the  distal  less  commonly  than  the 

others.  The  distal  fossa  is 
smaller  than  the  -central  and 
is  located  between  the  disto- 
lingual  and  disto-buccal  cusps 
and  the  distal  marginal  and 
oblique  ridges.  Its  longest  di- 
mension is  disto-lingually  in 
which  direction  it  is  traversed 
by  the  disto-lingual  groove. 
This  latter  has  its  terminations 
in  the  lingual  pit  near  the  cen- 
ter of  the  lingual  surface  and 
a  pit  in  the  distal  fossa.  It  is 
parallel  to  the  oblique  ridge, 
dividing  the  disto-lingual  cusp 
from  this,  and  is  usually  the 
seat  of  a  fissure,  the  result  of 
faulty  union  of  the  develop- 
mental lobes  of  the  crown. 
The  distal  groove  passes 
through  this  fossa,  crossing  the 
oblique  ridge  anteriorly  and  the  distal  marginal  ridge  posteriorly. 

The  Buccal  Surface  (Fig.  53). — This  is  bounded  by  four  margins, 
of  which  the  occlusal  is  irregular,  sha  p  and  prominent,  being  formed 
by  the  buccal  marginal  ridge  and  the  two  buccal  cusps,  the  cervical  is 
almost  straight,  while  the  mesial  and  distal  are  not  well  marked,  the 
distal  being  less  so  than  the  mesial.  The  two  latter  are  rounded 
and  fade  into  the  respective  faces  of  the  crown.  They  converge  from 
the  occlusal  surface  to  the  cervix,  so  that  when  the  tooth  is  viewed 
from  the  buccal  face  the  bell-shape  of  its  crown  is  noticeable.  For 
the  most  part  the  surface  is  slightly  convex  having,  however,  a  depres- 
ion  near  its  center  in  which  is  frequently  located  a  buccal  pit.  The 
uccal  groove  divides  it  into  two  lobes  and  usually  terminates  in  the 


Fig.  55. — Left  Upper  First  Molar. 
Mesial  Surface. 


THE    UPPER    FIRST    MOLAR. 


35 


buccal  pit,  but  the  depression  is  sometimes  continued  rootward  and  is 
continuous  with  that  between  the  two  buccal  roots.  At  the  cervix 
there  is  a  ridge  of  enamel,  the  cervical  ridge,  which  gives  prominence 
to  this  line. 

The  Lingual  Surface  (Fig.  54). — This  is  somewhat  similar  in  out- 
line to  the  buccal,  but  is  narrowed  mesio-distally  at  the  cervix  as  the 
sides  converge  to  a  single  root  instead  of  two  as  upon  the  buccal  surface. 
The  surface  is  more  convex  than  the  buccal,  but,  like  it,  is  often  the 
seat  of  a  pit  near  its  center,  the 
lingual  pit,  in  which  the  disto- 
lingual  groove  terminates.  The 
depression  caused  by  this  groove 
is  often  continued  rootward, 
dividing  the  surface  into  two 
lobes,  and  being  continuous 
with  a  longitudinal  depression 
upon  the  lingual  root.  Th' 
distal  lobe  is  rounded  in  every 
direction,  its  distal  portion  be- 
ing continuous  with  the  distal 
face  of  the  crown  without  de- 
marcation. The  mesial  lobe 
resembles  this  in  character  ex- 
cept that  its  anterior  margin  is 
more  defined.  In  those  teeth 
with  five  cusps  this  lobe  pre- 
sents near  the  occlusal  margin 
a  rounded  cingule,  whose  lin- 
gual  side   is   continuous    with 

the  lingual  face  of  the  crown,  but  which  is  separated  from  the  mesio- 
lingual  cusp  by  a  groove,  the  mesio-lingual  groove.  This  latter 
often  terminates  distally  by  uniting  with  the  disto-lingual  groove,  but 
frequently  at  each  extremity  it  fades  away  into  the  surface  of  the 
tooth.  The  cervical  line  is  almost  straight,  the  mesial  and  distal 
margins  are  curved  and  converge  toward  the  cervix,  while  the  occlusal 
margin  resembles  that  of  the  buccal  face  except  that  the  cusp  points 
are  not  so  sharp  and  the  marginal  ridge  is  more  rounded. 

The  Mesial  Surface  (Fig.  55). — While  this  is  generally  convex 
bucco-lingually  near  the  occlusal  margin,  in  its  gingival  two-thirds 
it  is  either  flat  or  it  may  be  slightly  concave.  It  is  either  convex 
or   nearly  flat   occluso-gingivally,   and   the  most  prominent  point  is 


Fig.  56. 


-Left  Upper  First  Molar. 
Distal  Surface. 


36 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


slightly  above  the  occlusal  margin  where  the  tooth  is  in  contact  with 
the  second  bicuspid.  The  surface  is  bounded  by  four  margins — 
the  cervical  is  usually  concave  in  an  occlusal  direction,  while  the 
occlusal  is  concave  in  a  cervical  direction  because  of  the  mesial  groove 
which  is  sometimes  continued  for  a  short  distance  upon  this  surface. 
The  buccal  and  lingual  margins  are  convex  and  converge  to  the  occlusal 
surface.  They  are  rounded,  the  former  being  better  defined  than  the 
latter.  The  lingual  margin  is  modified  by  the  presence  or  absence  of 
the  lingual  cingule,  the  location  of  the  notch  caused  by  the  mesio- 
lingual  groove  varying  according  to  the  height  of  the  cingule. 

The  Distal  Surface  (Fig.  56). — Four 
sided,  this  surface  resembles  the  mesial 
in  general  outline.  It  is  generally  con- 
vex, except  that  often  the  distal  groove 
is  continued  and  makes  a  slight  longi- 
tudinal depression  near  its  center.  The 
occlusal  margin  is  more  deeply  notched 
than  that  of  the  mesial  surface,  the  cer- 
vical line  is  nearly  straight  or  concave 
occlusally  while  the  buccal  and  lingual 
margins  are  rounded,  the  former  being 
less  well  defined  than  the  latter. 

The  Roots  (Figs.  53  and  54). — These 
are  three  in  number  and  are  named  from 
their   location,    the  mesio-buccal,   disto- 

FiG.  s7- — Right  Upper  First  Molar.  ,  ,,,.,,_, 

Cross-section  below  cervix,  showing  buccal  and  Imgual.  They  are  not  given 
the  pulp  chamber  and  entrances  to  ^ff  directly  from  the  basc  of  the  crown, 

the  pulp  canals.  •' 

but  the  division  which  results  in  them 
occurs  usually  about  one-third  the  distance  from  the  cervix  to  the 
root  apices. 

The  mesio-buccal  root  (Fig.  55)  is  flattened  antero-posteriorly, 
and  is  next  to  the  lingual  in  size  and  length.  Viewed  from  its  mesial 
side,  it  is  nearly  equal  in  width  to  half  the  crown  and  its  sides  slowly 
converge  to.  near  its  end  when  they  meet  in  a  blunt,  rounded  point. 
From  this  view  the  root  is  inclined  buccally,  while  viewed  from  the 
buccal  side,  it  is  seen  to  have  a  mesial  inclination  in  its  first  third, 
curving  then  in  a  distal  direction  to  its  extremity.  It  is  thin  and  flat 
mesio-distally. 

The  disto-buccal  root  (Fig.  56)  is  the  smallest.  It  is  narrower 
bucco-lingually  than  the  mesio-buccal  and  is  short.  Its  sides  gradually 
incline  to  a  more  or  less  pointed  apex,  and  it  is  slightly  flattened  mesio- 


THE    UPPER    FIRST    MOLAR. 


37 


distally.  In  its  first  third  it  is  inclined  distally,  but  in  the  remainder 
of  its  extent  it  is  usually  inclined  mesially,  approaching  the  mesio- 
buccal  root. 

The  lingual  root  (Fig.  54)  is  the  largest  and  usually  the  longest  of 
he  three  roots.  It  is  somewhat  flattened  bucco-lingually,  and  it  is 
either  nearly  straight  or  slightly  curved,  in  which  latter  instance  its 
extremity  is  inclined  buccally.  It  diverges  markedly  from  the  buccal 
roots  in  a  lingual  direction.  Viewed  from  the  lingual  face  the  sides 
of  the  root  are  markedly  convergent, 
sloping  from  the  base  of  the  crown 
to  a  somewhat  rounded  apex. 
This  face  of  the  root  often  pre- 
sents a  longitudinal  depression 
which  is  continuous  with  that  on 
the  lingual  side  of  the  crown. 

The  Pulp  Cavity  (Fig.  57).— 
The  pulp  cavity  is  easily  separable 
into  the  pulp  chamber  and  the  pulp 
canals,  of  which  the  former  is  ap- 
proximately the  shape  of  the  exterior 
of  the  crown  of  the  tooth,  while  the 
latter,  which  are  three  in  number, 
correspond  to  the  general  external 
shape  of  the  roots.  The  pulp 
chamber  is  characterized  by  four 
horns  or  depressions  in  its  occlusal 
wall,  one  entering  each  of  the  four 
cusps.  Its  four  lateral  walls  are 
parallel  to  the  sides  of  the  crown 
and  are  generally  flat.  In  bell- 
shaped  teeth  they  converge  from 

the  occlusal  wall  to  the  floor  (Fig.  58)  which  is  much  smaller  than  the 
occlusal  wall,  while  in  teeth  whose  crown  walls  are  nearly  parallel 
without  constriction  at  the  neck,  the  lateral  pulp  chamber  walls  are 
similarly  disposed. 

The  horns  of  the  pulp  chamber  are  marked  and  penetrating  and 
often  persist  in  mature  teeth  as  deep  recesses  in  the  dentin.  The  floor 
of  the  pulp  chamber  presents  the  three  openings  for  the  pulp  canals. 
In  the  young  adult  tooth  these  are  in  the  form  of  funnel-shaped  open- 
ings. As  age  increases,  the  size  of  the  pulp  chamber  decreases.  The 
thickening  of  the  lateral  walls  encroaches  upon  the  pulp  chamber,  the 


Fig.  58. — Right  Upper  First  Molar. 
Longitudinal  section  cut  through  the  pulp 
canals  of  the  buccal  roots,  showing  the 
pulp  chamber  and  its  horns. 


38  THE  ANATOMY  OF  THE  HUMAN  TEETH. 

funnel-like  openings  to  the  canals  become  simply  small  apertures  and 
the  canals  are  much  reduced  in  size. 

The  lingual  canal  (Fig.  57)  is  the  largest  and  most  accessible.  It 
does  not  conform  to  the  flattened  shape  of  the  root  but  is  usually  cir- 
cular, decreasing  gradually  in  caliber  to  the  apex,  and  following 
the  curvature  of  the  root  already  noted.  The  entrance  to  it  is  directly 
under  the  middle  of  a  line  drawn  from  the  summit  of  one  lingual  cusp 
to  the  other.  The  mesio-buccal  canal  (Fig.  58)  is  next  in  size  and 
length.  The  entrance  to  it  is  very  near  the  mesio-buccal  angle  of  the 
tooth,  slightly  anterior  to  the  summit  of  the  mesio-buccal  cusp.  It 
is  flat  and  ribbon-like  and  follows  the  curvature  of  the  root.  The  disto- 
buccal  canal  (Fig.  58)  is  small  and  thread-like.  Its  entrance  is  approx- 
imately under  the  disto-buccal  cusp.     It  is  short  and  difhcult  to  enter. 

THE  UPPER  SECOND  MOLAR. 

The  crown  of  this  tooth  differs  from  the  first  molar  in  any  given 
denture  in  that  it  is  flattened  mesio-distally,  with  a  rounding  of  the 
mesio-lingual  and  disto-buccal  angles;  its  cusps  are  not  so  long  and 
their  summits  are  nearer  the  center  of  the  tooth;  it  almost  never  pos- 
sesses   a  fifth  cusp  or  cingule,  and  the 
disto-lingual    cusp    is  relatively  smaller 
than  that  of  the  first  molar. 

The  Occlusal  Surface  (Fig.  59). — 
When  the  crown  is  viewed  from  the 
occlusal  surface  this  latter  is  seen  to  be 
rhomboidal  in  outline  but  with  the  angles 
more  rounded  than  those  of  the  first 
molar  and  with  the  lingual  margin  almost 
semicircular.  The  mesial  marginal,  the 
distal  marginal,  the  buccal  and  the 
lingual  marginal  ridges  are  formed  as 
they  are  in  the  first  molar.     In  this  tooth 

Fig.     59. — Left   Upper   Second       ,,     '  i     ,  rj^i        .^^  :^ 

Molar.    Occlusal  Surface.  ^^ey   are    more   rounded.      The  mesio- 

buccal  cusp  has  four  ridges  descending 
from  its  summit,  one  each  in  a  buccal,  lingual,  mesial  and  distal  direc- 
tion. It  is  smaller  and  less  sharp  than  the  corresponding  cusp  of  the 
first  molar.  The  disto-buccal  cusp  is  usually  small  and  pressed  in 
toward  the  center  of  the  crown  by  the  rounding  of  the  disto-buccal  angle. 
Its  buccal  ridge  is  absent  or  barely  distinguishable.  The  mesio-lingual 
cusp  is  usually  the  largest  cusp  and  is  well  rounded  and  without  a  clearlv 


THE  UPPER  SECOND  MOLAR. 


39 


defined  point.  It  has  ridges  which  pass  mesially,  distally  and  buccally : 
the  latter  is  heavy  and  strong  and  assists  in  forming  the  obhque  ridge. 
The  lingual  surface  of  the  cusp  is  much  rounded.  The  dislo-lingual 
cusp  varies  much  in  size  and  form.  It  is  usually  relatively  smaller 
than  that  of  the  first  molar.  Often  it  is  little  more  than  an  enlarge- 
ment of  the  distal  marginal  ridge,  with  which  its  buccal  ridge  is  contin- 
uous. Its  distal  and  lingual  faces  are  much  rounded.  The  central 
fossa  is  not  so  deep  as  that  of  the  first  molar,  though  similarly  its  walls 
are  formed  by  the  two  buccal  cusps  and  the  mesio-lingual  together  with 


Fig.  6o. — Left  Upper  Second  Molar 
Buccal  Surface. 


Fig.  6i. 


-Left  Upper  Second  Molar. 
Lingual  Surface. 


the  mesial  marginal  and  oblique  ridges.  The  mesial  groove,  the  buccal 
groove  and  the  distal  groove  all  pass  from  it  in  these  respective  directions. 
It  has  a  pit,  the  central  pit,  in  its  center,  and  the  distal  fossa  has,  simi- 
larly, the  distal  pit.  From  the  latter  fossa  the  distal  groove  passes  to 
the  distal  surface  and  the  disto-lingual  to  the  lingual  surface,  ending 
on  the  latter  usually  in  the  lingual  pit. 

The  Buccal  Surface  (Fig.  60). — This  resembles  that  of  the  first 
molar  so  closely  that  only  their  points  of  difference  need  to  be  pointed 
out.     The  occlusal  margin  has  the  same  outline  as  that  of  the  first 


40 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


Fig.  62. 


-Left  Upper  Second  Molar. 
Mesial  Surface. 


from  that  of  the  first  molar  ex- 
cept that  it  is  much  more  con- 
vex and  the  fifth  cusp  is  almost 
never  present  to  modify  the  form 
of  its  mesial  portion. 

The  Mesial  Surface  (Fig.  62). 
— This  resembles  closely  the  cor- 
responding surface  of  the  upper 
first  molar,  but  is  relatively 
smaller  and  is  often  concave 
from  buccal  to  lingual  side.  Its 
lingual  margin  is  less  well  de- 
fined than  its  mesial. 

The  Distal  Surface  (Fig.  63) . 
— Usually  more  convex  than  this 
surface  of  the  first  molar,  and 
relatively  shorter  occluso-gingi- 
vally,  the  distal  surface  of  this 
tooth  resembles  in  other  respects 


molar  except  that  the  smaller 
proportionate  size  of  the  disto- 
buccal  cusp  causes  this  portion 
to  be  slightly  altered.  The  distal 
margin  is  more  rounded  and  less 
pronounced  than  that  of  the  first 
molar,  but  the  other  two  margins 
are  similar.  The  buccal  groove 
continues  upon  the  buccal  face, 
from  the  occlusal  surface,  some- 
times to  the  point  of  bifurcation 
of  the  roots,  less  rarely  ending  in 
a  buccal  pit.  The  lobe  of  the 
crown  mesial  to  the  depression 
is  always  larger  than  the  distal 
lobe.  The  cervical  ridge  is  not 
so  frequently  marked. 

The    Lingual   Surface    (Fig. 
61). — This    differs    in    no    wise 


Fig.  63. — Left  Upper  Second  Moalr. 
Distal  Surface. 


THE    UPPER    THIRD    MOLAR, 


41 


Fig.  64. — Right  Upper  Second 
Molar.  Cross-section  at  cervix 
showing  pulp  chamber. 


its  mesial  neighbor.     The  varying  size  and  portion  of  ihe  disto-lingual 

cusp  influence  the  exact  form  of  this  face 

of  the  crown. 

The  Roots. — Alike  in  number  and  gen- 
eral form  to  those  of  the  first  molar,  the 

roots  of  the  second  differ  in  some  respects 

from  them.      The  mesio-buccal  (Fig.  62) 

is   flattened   antero-posteriorly,   the   disto- 

buccal  (Fig.  63)  is  nearly  conical,  while  the 

lingual  root  (Fig.  61)  is  longest,  largest  and 

flattened   bucco-lingually   but   seldom   ex- 
hibits the  depression  observed  on  this  root 

of  the  first  molar.     The  two  buccal  roots 

have  a  distinct  distal  inclination  and  tend 

to   converge   at  their  apices.      The  disto- 

buccal   root  occupies  a  position  relatively 

more  lingual  than  that  of  the  first 
molar  because  of  the  flattening  of 
the  disto-buccal  angle  of  the  crown. 
The  Pulp  Cavity. — The  differ- 
ences between  the  form  of  this  and 
that  of  the  first  molar  correspond 
to  the  differences  in  the  surface 
forms  of  the  tAvo  teeth. 

The  pulp  chamber  is  flattened 
mesio-distally  (Fig.  64)  and  the 
entrances  to  the  canals  are  rela- 
tively nearer  together  and  that  of 
the  disto-buccal  canal  is  more 
lingually  located.  The  horns  of 
the  pulp  chamber  are  four  in 
number  but  are  smaller  and  less 
penetrating  than  those  of  the  first 
molar.  The  root  canals  have  the 
same  shape  as  those  of  the  first 
molar  but  are  smaller  and   more 


-Right  Upper  Second  Molar. 


Fig.  65 
Longitudinal  Section  cut  through  mesio- 
buccal  root  canal,  showing  pulp  chamber,      difficult  tO  enter   (Fig.  65). 

THE  UPPER  THIRD  MOLAR. 

Greater  variation  occurs  in  the  form  of  this  tooth  than  in  that  of 
any  other  in  the  dental  series.     In  its  typical  form  it  has  only  three 


42 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


cusps,  the  disto-lingual  cusp  having  disappeared,  while  in  its  most 
strongly  developed  form  this  is  present  but  is  much  reduced  in  size 
by  comparison  with  the  other  cusps  of  the  tooth.  Many  atypical 
teeth  are  observed  in  which  the  cusp  development  is  difiScult  to  classify. 
A  description  will  be  given  of  the  typical  tooth. 

The  Occlusal  Surface  (Fig.  66). — This  is  marked  by  the  presence  of 
a  mesio-buccal,  a  disto-buccal  and  a  mesio-lingual  cusp.  The  disto- 
lingual  is  represented  only  in  the  distal  marginal  ridge,  or  may  be  en- 
tirely absent  when  the  oblique  ridge  forms  the  posterior  margin  of  the 
surface.  The  buccal  cusps  are  like  in  form  to  those  of  the  first  and 
second  molars  except  that  they  are  shorter  and  smaller.     The  mesio- 


FlG.  66.— Left  Upper  Third  Molar. 
Occlusal  Surface. 


Fig.  67. 


-Left  Upper  Third  Molar. 
Buccal  Surface. 


lingual  cusp  is  large  and  rounded  and  the  central  fossa  is  well  defined ; 
usually  many  small  ridges  descend  from  the  cusps  into  it.  The  mesial 
marginal  ridge  is  well  defined,  the  buccal  depends  in  character  upon 
the  buccal  cusps  and  the  lingual  is  usually  poorly  discernible.  The 
posterior  margin  may  be  either  formed  by  the  triangular  ridge  or  the 
distal  marginal  ridge  may  be  present. 

The  Buccal  Surface  (Fig.  67). — In  typical  teeth  this  resembles  the 
buccal  face  of  the  second  molar  but  is  smaller  in  extent,  more  rounded, 
and  its  distal  lobe  is  poorly  defined. 

The  Lingual  Surface  (Fig.  68). — Variations  in  the  form  of  this 
surface  are  caused  by  the  presence  or  absence  of  the  disto-lingual  cusp 
— when  present,  this  cusp  surmounts  a  lobe  of  this  surface  which  is 
partially  divided  from  the  mesial  lobe  by  the  disto-lingual  groove. 
In  this  event  the  mesial  lobe  resembles  that  of  the  second  molar  but 


THE  UPPER  THIRD  MOLAR. 


43 


is  even  more  convex.  When  the  lingual  side  is  surmounted  only  by 
one  cusp,  it  is  much  rounded  and  convex  and  joins  the  mesial  and  distal 
faces  almost  without  line  of  demarcation. 

The  Mesial  Surface  (Fig.  69). — This  resembles  that  of  the  second 
molar  in  being  flat  and  sometimes  concave  from  buccal  to  lingual 
sides,  but  it  is  smaller  in  extent  of  surface. 

The  Distal  Surface  (Fig.  70). — While  it  is  usually  rounded  from 
buccal  to  lingual  side,  being  always  so  when  the  disto-lingual  cusp  is 
absent,  this  surface  may  also  be  flat  or  even  concave,  when  the  crown 
has  four  cusps.  It  is  always  smaller  in  area  than  the  mesial  surface  or 
than  the  distal  surface  of  the  first  and  second  molars. 


Fig.  68. 


-Left  Upper  Third  Molar. 
Lingual  Surface. 


Fig.  69. — Left  Upper  Third  Molar. 
Mesial  Surface. 


The  Roots. — These  vary  much  even  in  teeth  which  are  typical  in 
regard  to  their  crowns.  There  are  sometimes  three  roots,  a  mesio- 
buccal,  a  disto-buccal  and  a  lingual,  which  are  usually  short  and  have 
a  distal  and  a  lingual  curvature.  These  are  sometimes  fused  together 
throughout  most  of  their  length.  Occasionally  only  one  root  is  seen 
caused  by  the  complete  fusion  of  the  roots.  Occasionally  also  four 
roots  may  be  found  (Fig.  71). 

The  Pulp  Cavity. — The  external  form  of  the  crown  largely  deter- 
mines the  form  of  the  pulp  cavity,  so  that  in  trituberculate  teeth  this 
cavity  is  triangular  in  cross-section  while  in  quadriluberculate  teeth, 
it  has  the  general  form  of  the  pulp  chamber  of  the  other  upper  molars. 
Its  lateral  walls  converge  more  to  the  floor  of  the  pulp  chamber  which 
is  situated  at  a  higher  level  than  that  of  the  pulp  chamber  of  the  second 
molar.     The  horns  of  the  pulp  chamber  are  less  well  defined  and  are 


44 


THE  ANATOMY  OF  THE  HUMAN  TEETH. 


shorter  than  those  of  the  other  upper  molars  and  correspond  in  number 
to  the  number  of  cusps  in  any  given  tooth.  The  pulp  canals  usually 
correspond  in  number  with  the  number  of  roots  except  that  in  teeth 
in  which  the  roots  have  fused  into  a  single  one,  there  may  be  three  or 
even  four  root  canals,  which  sometimes  have  separate  apical  fora- 
mina, or  again  may  unite  before  this  is  reached  and  have  a  common 


Fig.  70. — Left  Upper  Third  Molar. 
Distal  Surface. 


"  Fig.   71.— Left  Upper  Third  Molar. 
With  roots  not   completely    developed 

and    atypical    in    having    four    roots. 

Shov/ing  large  patulous  openings  into 

root  canals. 


termination.  Occasionally  in  the  single  rooted  tooth  there  is  only 
one  large  canal,  the  walls  of  which  are  continuous  with  those  of  the 
pulp  chamber  and  converge  to  a  small  foramen  at  the  root  apex. 
Where  more  than  one  canal  exists,  they  are  small  and  thread-like, 
quite  short  as  the  roots  are  short,  and  the  openings  from  the  pulp 
chamber  into  them  are  very  close  together. 

THE  LOWER  FIRST  MOLAR. 

The  largest  tooth  of  the  human  series  is  the  lower  first  molar,  which 
is  longer  mesio-distally  than  the  upper  first  molar,  and  is  of  about 
equal  width.     The  five  surfaces  of  its  crown  may  be  described. 

The  Occlusal  Stir  face  (Fig.  72). — This  is  irregularly  trapezoidal 
in  outline,  its  four  margins  usually  being  rounded.  The  buccal  and 
lingual  are  more  convex  than  the  mesial  and  distal  which  may  be  al- 
most straight.  These  latter  converge  toward  the  lingual  side  in 
consequence  of  which  this  is  shorter  than  the  buccal.  Five  cusps  are 
usually  present,  three  upon  the  buccal  side  and  two  upon  the  lingual. 
A  central  fossa  is  formed  and  occupies  nearly  the  center  of  the  surface 
and   from   this   radiate   grooves  separating  the   cusps.     Four   ridges 


THE    LOWER    FIRST    MOLAR. 


45 


bound  the  surface.  The  mesial  marginal  ridge  is  the  best  defined  of 
these.  It  passes  from  the  mesio-buccal  to  the  mesio-lingual  angle  of 
the  crown,  is  concave  rootward  and  is  usually  crossed  near  its  center 
by  the  mesial  groove.  It  is  continuous  at  its  buccal  and  lingual  ex- 
tremities with  the  marginal  ridges  of  these  names.  The  buccal  marginal 
ridge  is  poorly  defined,  is  bowed  in  a  buccal  direction,  and  is  made  up  of 
the  ridges  descending  mesially  and  distally  from  the  three  buccal  cusps. 
The  distal  marginal  ridge  is  not  so  prominent  as  the  mesial  but  is  like 
it  in  other  respects.  It  is  commonly  crossed  by  the  distal  groove. 
The  lingual  marginal  ridge  is  made  up  of  the  ridges  descending  ante- 
riorly and  posteriorly  from  the  two  lingual  cusps.  It  is  cut  near  its 
center  by  the  lingual  groove  and 
is  somewhat  sharper  than  the 
buccal  marginal  ridge. 

The  mesio-buccal  cusp  is 
usually  the  largest  and  some- 
times the  longest  cusp  of  this 
tooth.  It  is  a  rounded  elevation 
with  ridges  descending  mesially, 
buccally,  and  distally,  and  some- 
times two  or  more  toward  the 
central  fossa  from  its  lingual 
sides.  The  names  of  these 
ridges  correspond  to  the  direc- 
tion in  which  they  descend  from  the  point  of  the  cusp,  except  that  the 
lingual  ridge  is  usually  spoken  of  as  the  triangular.  It  is  the  most 
sharply  defined  of  all. 

The  buccal  cusp  is  next  in  size  of  the  buccal  series  of  cusps,  being 
intermediate  in  size  and  position  between  the  mesio-buccal  and  the 
disto-buccal  cusp.  It  has  also  four  ridges  which  pass  in  a  buccal, 
lingual,  mesial  and  distal  direction  respectively.  The  lingual  ridge 
descends  into  the  central  fossa  and  is  called  the  triangular  ridge. 
The  disto-buccal  cusp  is  separated  from  the  last  described  cusp  by 
the  disto-buccal  groove.  It  varies  in  size  and  position.  It  is  more 
prominent  buccally  where  it  is  of  greatest  size,  but  when  found  of 
small  size  -it  is  located  nearer  the  distal  face  of  the  tooth  and  there  is 
a  corresponding  increase  in  the  size  of  the  buccal  cusp. 

The  disto-buccal  is  always  the  smallest  cusp.  Three  ridges,  a 
mesial,  a  distal  and  a  triangular,  may  usually  be  observed,  but  its 
buccal  surface  is  rounded  and  convex. 

The  lingual  cusps  are  sharper  than  the  buccal  cusps.     The  mesio- 


FiG.  72. — Right  Lower  First  Molar. 
Occlusal  Surface. 


46 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


lingual  is  sharp  and  prominent  in  the  unworn  tooth  and  its  summit 
is  near  the  mesio-lingual  angle.  Its  lingual  surface  is  continuous 
with  that  of  the  crown  but  ridges  descend  mesially,  distally,  and 
buccally.  The  triangular  ridge  passes  into  the  central  fossa  and  ter- 
minates at  the  mesial  groove  opposite  the  triangular  ridge  from  the 
mesio-buccal  cusp.  These  two  ridges  are  separated  from  the  mesial 
marginal  ridge  by  a  shallow  depression  running  bucco-lingually. 
The   disto-lingual   cusp   is   usually   smaller   than   the   mesio-lingual, 


Fig.  73. — Right  Lower  First  Molar. 
Buccal  Surface. 


Fig.  74. — Right  Lower  First  Molar. 
Lingual  Surface. 


but  like  it,  is  pointed  and  has  three  ridges  descending  from  its  summit, 
and  otherwise  resembles  it  in  shape. 

The  central  fossa  occupies  approximately  the  center  of  the  occlusal 
surface,  and  is  broad  and  shallow.  The  mesial  and  distal  marginal 
ridges  and  the  five  cusps  contribute  to  form  its  walls.  The  mesial 
groove  passes  from  it  to  the  mesial  surface,  the  buccal  groove  is  well 
marked,  usually  the  seat  of  a  fissure,  and  passes  buccally  between  the 
mesio-buccal  and  buccal  cusps;  the  disto-buccal  groove,  also  frequently 
the  seat  of  a  fissure,  passes  between  the  buccal  and  disto-buccal  cusps; 
the  distal  groove  crosses  the  disto-marginal  ridge  and  the  lingual  groove 


THE    LOWER    FIRST    MOLAR. 


47 


passes  between  the  lingual  cusps,  although  in  some  instances  it  is  very 
poorly  marked.  The  floor  of  the  central  fossa  is  flat  and  frequently 
small  tubercles  of  enamel  are  found  divided  from  each  other  by  fine 
grooves.  The  central  pit,  a  fault  in  the  enamel,  is  usually  found 
where  the  buccal  and  lingual  grooves  meet  and  a  distal  pit  often  at  the 
occlusal  termination  of  the  disto-buccal  groove. 

The  Buccal  Surface  (Fig.  73). — This  is  trapezoidal  in  shape,  and  is 
convex  mesio-distally  and  occluso-gingivally.     The  mesial  and  distal 


Fig.  75. — Right  Lower  First  Molar. 
Mesial  Surface. 


Fig.  76. — Right  Lower  First  Molar. 
Distal  Surface. 


margins  are  much  rounded  and  ill  defined,  the  occlusal  margin  is 
marked  by  three  elevations,  the  cusps,  and  two  grooves,  and  the  cer- 
vical is  usually  convex  rootward  and  marked  with  a  prominent  ridge 
of  enamel,  the  cervical  ridge.  The  buccal  groove  crosses  the  surface 
a  little  mesial  to  its  center  and,  decreasing  in  depth,  is  continuous  with 
the  depression  caused  by  the  bifurcation  of  the  roots,  or  it  terminates 
half  way  between  the  occlusal  and  cervical  margin  in  a  well-defined  de- 
pression, the  buccal  pit. 

The  disto-lingual  groove  is  less  deep  at  the  occlusal  margin  and 


48 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


terminates  by  disappearing  about  half  way  from  the  cervix.  These 
grooves  divide  the  buccal  surface  into  lobes  of  which  the  mesial  is 
most  strongly  marked,  the  central  and  distal  being  more  rounded  and 
usually  uniting  at  the  cervical  portion,  being  separated  at  their  occlusal 
portion  by  the  disto-buccal  groove. 

The  Lingual  Surface  (Fig.  74). — This  is  convex  in  all  directions 
but  is  less  so  occluso-gingivally  than  the  buccal  because  of  the  sharp- 
ness of  the  lingual  cusps.  Its  mesial  and  distal  margins  are  much 
rounded  and  converge  to  the  cervical  which  is  convex  rootward.  The 
occlusal  margin  is  marked  by  the  two  cusps  and  the  lingual  groove. 
The  latter  is  often  poorly  marked  although  it  is  occasionally  deep  but 

usually  disappears  about  the  center 
of  the  surface,  and  the  division  of 
this  surface  by  it  into  two  lobes  is 
not  usually  distinct. 

The  Mesial  Surface  (Fig.  75). — 
While  it  is  generally  convex  and 
usually  so  near  the  occlusal  margin 
where  it  affords  a  point  of  contact 
with  the  second  bicuspid,  this  sur- 
face is  sometimes  flat  and  usually 
a  concavity  may  be  noted  near  the 
cervical  line.  The  occlusal  margin 
is  notched  by  the  mesial  groove 
between  the  two  mesial  cusps,  the 
ateral  margins  are  rounded  and  convex  in  an  occlusal  direction. 

The  Distal  Surface  (Fig.  76). — This  resembles  the  mesial  face  of 
the  crown  in  outline,  but  is  more  convex.  Its  cervical  and  lingual 
margins  are  like  those  of  the  mesial  but  the  varying  size  and  position 
of  the  disto-buccal  cusp  determine  the  occlusal  and  buccal  margins. 
The  latter  is  rounded  and  the  former  is  marked  by  the  distal  groove. 
These  unite  at  the  disto-buccal  cusp,  the  position  of  which  determines 
whether  the  occlusal  margin  is  long  or  short. 

The  Roots. — There  are  two  roots  (Fig.  73),  named  from  their  posi- 
tions, mesial  and  distal.  They  are  both  broad  and  much  flattened 
mesio-distally.  The  point  of  bifurcation  is  about  one-fourth  the  dis- 
tance from  the  cervix  to  the  root  apices.  The  mesial  root  when  viewed 
from  the  mesial  surface  (Fig.  75)  is  seen  to  be  flat,  its  sides  converging 
but  slightly  to  a  blunt  apex.  On  both  its  mesial  and  distal  surfaces 
a  longitudinal  depression  running  the  length  of  the  root  may  be  ob- 
served.    The  mesial  and  distal  sides  are  nearly  parallel  until  the  apex 


Fig.  77. — Right  Lower  First  Molar. 
Cross-section  at  cervix,  showing  the 
pulp  chamber  and  entrances  to  the  pulp 
canals. 


THE    LOWER    SECOND    MOLAR. 


49 


is  reached.  The  root  is  curved  mesially  so  that  its  lower  third  has  a 
decided  distal  turn.  The  distal  root  is  usually  straight  and  is  flattened 
also  mesio-distally.  It  is  not  marked  by  longitudinal  depressions  on 
its  mesial  and  distal  sides,  terminates  in  a  sharper  apex  than  the 
mesial  root,  and  is  not  so  long. 

The  Pulp  Cavity.— The  chamber  corresponds  in  general  to  the 
shape  of  the  crown,  being  quad- 
rilateral in  horizontal  cross- 
section  (Fig.  77).  The  occlusal 
wall  of  the  chamber  in  young 
teeth  has  five  horns  which  are 
in  relation  with  the  five  cusps, 
but  these  are  very  poorly  marked 
because  of  the  shortness  of  the 
cusps.  The  lateral  walls  are 
four  in  number,  the  buccal  wall 
being  of  greatest  extent.  These 
converge  to  the  floor  (Fig.  77) 
which  is  concave  bucco-lin- 
gually  and  convex  mesio-distally. 
The  buccal  and  lingual  walls 
meet  in  a  trough- like  depres- 
sion which  dips  down  anteriorly 
and  posteriorly  to  the  entrance 
into  the  pulp  canals.  In  any 
but  old  teeth  the  mesial  and 
distal  walls  (Fig.  78)  are  contin- 
uous with  the  walls  of  the  pulp 
canals.  The  openings  to  the 
latter    are   funnel-like.      There 


Fig.  78. — Left  Lower  First  Molar.  Mesio- 
distal  longitudinal  section  cut  through  the 
buccal  cusps  and  the  pulp  canals,  showing 
pulp  chamber  and  canals. 


are  usually  two  canals  in  the  mesial  root  which  are  fine  and  thread- 
like and  round.  They  occasionally  meet  before  the  apex  of  the  root  is 
reached  and  terminate  in  a  common  foramen  although  they  usually 
make  exit  by  separate  foramina.  The  distal  pulp  canal  is  larger  and 
ovoid  in  cross-section  and  easily  entered. 

THE  LOWER  SECOND  MOLAR. 

The  crown  of  the  lower  second  molar  differs  from  that  of  the  first 
in  that  it  has  four  cusps  of  nearly  equal  size  instead  of  five.  In  other 
particulars  its  surface  form  is  very  similar. 

The  Occlusal  Surface  (Fig.  79). — The  occlusal  surface  presents 
4 


50  THE    ANATOMY    OF    THE    HUMAN    TEETH. 

for  examination  four  cusps  of  nearly  equal  size,  situated  near  its  four 
angles.  The  summits  of  the  cusps  are  nearer  the  center  of  the  crown 
than  are  those  of  the  first  molar  and  are  more  rounded.  The  out- 
line of  this  surface  is  more  rounded  than  that  of  the  first  molar,  the 
mesial  and  distal  margins  being  of  equal  length  and  convex.  The 
buccal  and  lingual  are  also  usually  of  equal  length  but  in  some  instances 
that  of  the  former  is  greater.  The  mesial  and  distal  marginal  ridges 
are  similar  to  those  of  the  first  molar,  and  the  surface  has  a  central 
fossa  from  which  a  mesial,  distal,  buccal,  and  lingual  groove  pass  to 
these  respective  borders.  The  central  fossa  is  well  defined  but 
shallower  than  that  of  the  first  molar.  The  triangular  ridges  from  the 
cusps  are  well  marked  and  between  these  the  grooves  meet  forming 

a  cruciform  sulcus.  Occasion- 
ally the  tooth  has  five  cusps 
when  the  anatomy  of  this  sur- 
face is  similar  to  that  of  the  first 
molar. 

The  Buccal  Surface  (Fig. 
80). — This  has  the  same  general 
form  of  that  of  the  first  molar, 
but  is  less  complicated  because 
of  the  absence  of  the  fifth  cusp. 
It  is  more  convex  than  that  of 
the  first  molar,  is  relatively 
Fig.  79--Right  Lower  Second  Molar.       smaller  in  extent  ahd  is  not  so 

Occlusal  Surface. 

definitely  divided  into  lobes  by 
the  buccal  groove.  This  latter  usually  terminates  by  blending 
with  the  buccal  surface  about  its  center  and  rarely  terminates  in  a 
buccal  pit. 

The  Lingual  Surface  (Fig.  81). — Except  that  it  is  smaller,  this 
resembles  the  lingual  face  of  the  first  molar  crown  so  closely  as  to 
require  no  separate  description. 

The  Mesial  Surface  (Fig.  82). — This  is  more  convex  than  that  of 
the  first  molar  but  is  like  it  in  other  respects. 

The  Distal  Surface  (Fig.  83). — The  absence  of  the  fifth  cusp  is 
responsible  for  the  dissimilarity  between  this  and  the  distal  surface 
of  the  first  molar.  It  resembles,  however,  the  mesial  surface  of  the 
second  molar,  being  slightly  more  rounded. 

The  Roots. — These  are  two  in  number  and  closely  resemble  the 
roots  of  the  first  molar.  They  are  not  quite  so  long,  do  not  exhibit 
the  longitudinal  depressions  seen  upon  the  roots  of  the  first  molar, 


THE    LOWER    SECOND    MOLAR. 


51 


Fig.  80. 


-Right  Lower  Second  Molar. 
Buccal  Surface. 


Fig.  81. — Right  Lower  SecondMolar. 
Lingual  Surface. 


Fig.  82. — Right  Lower  Second  Molar. 
Mesial  Surface. 


Fig   83. — Right  Lower  Second  Molar. 
Distal  Surface. 


52 


THE  ANATOMY  OF  THE  HUMAN  TEETH. 


terminate  in  sharper  apices  and  are  usually  inclined  to  the  distal  at 
their  extremities. 

The  Pulp  Cavity  (Fig.  84). — The  occlusal  wall  of  the  pulp  chamber 
has  only  four  rudimentary  horns,  the  floor  of  the  chamber  is  smaller 
and  the  openings  into  the  pulp  canals  are  closer  together  but  in  other 
particulars  this  is  similar  to  the  chamber  of  the  first  molar. 


THE  LOWER  THIRD  MOLAR. 

No  tooth  in  the  human  denture  is  subject  to  greater  variation  than 
the  lower  third  molar.  The  form  most  commonly  found  is  that  with 
four  cusps,  in  which  instance  the  crown  much  resembles  the  second 

molar.  Rarely  it  is  possessed  of  five 
cusps,  being  somewhat  similar  to  the 
first  molar  in  form.  Often  its  occlusal 
surface  is  much  broken  up  and  exhibits 
a  fossa  surrounded  by  a  number  of 
cusps  and  is  nearly  circular  in  outline. 
The  Surfaces. — When  four  cusps 
are  present,  and  this  is  the  commonest 
form,  the  occlusal  surface  resembles 
that  of  the  second  molar  except  that 
the  cusps  are  shorter,  the  fossa  is 
shallower  and  the  outlines  of  the  sur- 
face are  more  rounded.  When  several 
cusps  exist  the  grooves  separating  them 
radiate  from  the  central  fossa.  The 
buccal,  lingual,  mesial  and  distal  sur- 
faces resemble  those  of  the  second 
molar  if  the  tooth  has  four  cusps,  or 
those  of  the  first  if  it  has  five.  In 
other  forms  of  the  tooth  the  tendency 
to  roundness  of  these  surfaces  is  to  be  noted  and  it  is  usually  difficult 
to  perceive  any  line  of  demarcation  between  them. 

The  Roofs. — There  are  two  which  usually  resemble  the  other  lower 
molar  roots  except  that  they  are  shorter  in  proportion  to  the  size  of 
the  crown,  and  generally  have  a  marked  distal  curve  which  complicates 
the  extraction  of  the  tooth.  Often  the  roots  are  fused  and  sometimes 
throughout  their  whole  extent,  giving  thus  only  one  actual  root. 

The  Pulp  Cavity. — It  can  only  be  said  concerning  this  that  the 
chamber  corresponds  to  the  external  form  of  the  crown,  being  similar 
to  this  cavity  of  the  first  or  second  molar  according  as  the  crown  re- 


FiG.  84. — Left  Lower  Second 
Molar.  The  roots  have  not  been 
completely  developed.  Longitudinal 
section  through  mesial  root  showing 
pulp  cavity  and  method  of  its  division 
into  two  pulp  canals. 


THE    DECIDUOUS    TEETH.  53 

sembles  one  or  the  other  of  these  teeth.  In  other  instances  it  is  usually  a 
rounded  cavity  resembling  the  external  form  of  the  crown.  The 
pulp  canals  are  similar  in  number  to  those  of  the  first  molar  and  may 
be  found  separated  even  if  the  roots  of  the  tooth  are  fused.  In  rare 
instances  a  single  large  canal  terminating  in  a  single  small  apex  is  found. 

THE  INTERPROXIMAL  SPACES. 

The  relationships  of  the  various  portions  of  the  incisal  and  occlusal 
surfaces  of  the  teeth  in  the  occlusal  position  of  the  mandible  are  de- 
scribed in  the  chapter  on  Orthodontia  to  which  the  reader  is  referred 
for  details.  Figs.  85  and  86  illustrate  the  teeth  in  occlusion.  Ex- 
amination of  these  figures  will  show  that  each  tooth  is  also  in  contact 
■with  the  teeth  which  adjoin  it  on  either  side  at  a  point  about  one-third 
the  distance  from  the  incisal  or  occlusal  surface  to  the  gingival  mar- 
gin. This  is  spoken  of  as  the  "point  of  proximal  contact."  It  will 
be  observed  that  a  triangular  space  exists  between  this  point  and  the 
margin  of  the  alveolus,  which  is  known  as  the  interproximal  space. 
In  the  young  subject  this  space  is  almost  wholly  filled  with  the  soft 
tissue  of  the  gum  which  extends  nearly  up  to  the  proximal  contact 
points,  but  as  age  advances  the  sharply  defined  margin  of  the  alveolus 
becomes  blunted  and  the  gum  tissue  recedes  so  that  in  late  adult  life 
this  space  is  normally  more  incompletely  filled.  The  normal  proxi- 
mal contact  of  the  human  teeth  (man  being  the  only  animal  with  no 
diastema  in  the  denture)  protects  the  gum  tissue  between  the  teeth  and 
the  adjoining  gingival  attachment  from  injury  during  the  mastication 
of  hard  food.  Wherever  caries  has  destroyed  this  proximal  contact 
or  where  it  is  wanting  from  other  cause  there  is  danger  of  wounding 
the  gum  and  pericementum  in  the  proximal  space  by  the  wedging  of 
food  of  a  fibrous  character  between  the  teeth,  with  the  subsequent  for- 
mation of  pockets  between  the  free  margin  of  the  gum  and  the  tooth 
root.  The  food  wedged  into  this  space  can  only  be  removed  by  some 
mechanical  means  and  the  difficulty  increases  as  time  goes  on.  If 
allowed  to  remain  its  fermentation  is  attended  with  the  added  chem- 
ical and  bacterial  irritation  of  the  tissues  and  the  carious  process  is 
further  favored  From  these  facts  will  be  easily  seen  the  necessity  for 
the  present  practice  in  operative  dentistry  or  in  crown  and  bridge- 
work  for  a  complete  reestablishment  of  the  proximal  contact  points  in 
all  such  restorative  procedures. 

THE  DECIDUOUS  TEETH. 

The  temporary  or  deciduous  teeth  serve  for  purposes  of  masti- 
cation during  the  earlier  years  of  life  and  are  exfoliated  between  the 


54 


THE  ANATOMY  OF  THE  HUMAN  TEETH. 


fifth  and  the  twelfth  years  to  give  way  to  their  permanent  successors. 
They  are  less  highly  developed  for  functional  purposes  than  the  per- 
manent teeth  but  entirely  satisfy  the  requirements  of  the  food  habit 
of  these  early  years.  They  are  necessarily  smaller  than  the  permanent 
teeth  and  are  but  twenty  in  number. 

They  resemble  in  many  respects  the  permanent  teeth  as  regards 
external  form  and  internal  anatomy,  but  differ  in  some  particulars 
and  these  latter  must  be  pointed  out.     They  are  in  general  less  well 


I'lG.  85. — The  permanent  teeth  in  occlusion.     External  View. 
(American  Text-book  of  Prosthetic  Dentistry.) 

developed  as  to  surface  markings.  They  have  relatively  longer  roots 
but  these  are  relatively  smaller  than  those  of  the  permanent  teeth. 
This  latter  fact  accounts  for  the  constricted  neck  and  bell-shaped 
crown  characteristic  of  the  deciduous  teeth.  The  crowns  of  the  teeth 
are  shorter  in  relation  to  their  width  than  are  those  of  the  permanent 
teeth. 

The  Upper  Central  Incisor  (Fig.  89). — In  addition  to  being  much 
smaller  than  the  permanent  central  incisor,  the  crown  of  this  tooth 
is  less  well  marked  upon  its  surface.  The  labial  grooves,  the  lingual 
marginal  ridge  and  fossa  and  the  distal  angle  are  especially  lacking 
in  development.     Its  surfaces  are  much  rounded  and  its  neck  is  con- 


THE    DECIDUOUS    TEETH. 


55 


stricted.     The  root  is  relatively  longer  and  smaller  than  that  of  the 
permanent  tooth  but  resembles  it  in  other  particulars. 

The  Upper  Lateral  Incisor  (Fig.  89).— This  resembles  both  the 
permanent  lateral  and  the  deciduous  central  incisor.  It  has  the 
characteristics  of  the  former  except  in  a  modified  degree.  Its  surface 
markings  are  less  pronounced  than  are  those  of  the  permanent  lateral 
and  it  resembles  the  deciduous  central  except  that  its  width  is  less  and 
its  distal  angle  is  more  rounded.  It  is  a  more  delicately  shaped  tooth 
but  is  usually  equal  in  the  length  of  its  crown  to  the  central  and  fre- 
quently its  root  is  longer.     The  latter  resembles  that  of  the  permanent 


Fig.  86. — The  Occlusion  of  the  Teeth.     Lingual  View. 
(American  Text-book  of  Prosthetic  Dentistry.) 


lateral  incisor  in  other  particulars  except  of  course  that  it  is  relatively 
smaller. 

The  Upper  Cuspid  (Fig.  89). — The  resemblance  between  this  tooth 
and  that  of  the  permanent  series  is  marked,  but  sufficient  differences 
exist  between  them  to  easily  differentiate  the  two  teeth. 

The  crown  of  this  tooth  is  proportionately  shorter  and  more  rounded 
than  that  of  the  permanent  cuspid.  The  labial  surface  presents  a 
marked  labial  ridge  ascending  from  the  point  of  the  cusp,  and  the 
labial  grooves  are  much  nearer  the  angles  of  the  tooth.     The  angles 


56  THE    ANATOMY    OF    THE    HUMAN    TEETH. 

of  the  crown  are  much  nearer  the  cervical  line  than  those  of  the  per- 
manent cuspid  in  consequence  of  which  the  mesial  and  distal  cutting 
edges  are  relatively  longer  and  the  mesial  and  distal  surfaces  are 
smaller.  The  lingual  surface  has  a  marked  lingual  ridge  and  the 
surface  is  generally  rounded  and  convex.  The  root  is  proportion- 
ately smaller  than  that  of  the  permanent  cuspid  and  the  pulp  canal 
is  small  in  consequence,  but  the  pulp  chamber,  like  that  of  all 
the   deciduous  teeth,  is  relatively  large. 

The  Upper  First  Molar.— The  molar  teeth  of  the  deciduous 
series  are  totally  unlike  their  successors,  the  bicuspids,  and  partake 
chiefly  of  the  characteristics  of  true  molar  teeth.  The  crown  of 
the  first  upper  molar  usually  has  three   cusps,    two    on    the  buccal 

and  one  on  the  lingual  side. 
(Fig.  87.)  The  surface  is 
almost  quadrilateral  because 
the  large  size  of  the  lingual . 
cusp  serves  to  balance  the 
two  buccal  on  the  opposite 
side.  The  corners  of  the 
figure  are  much  rounded,  the 
sharpest  corner  being  the  mesio- 
FiG.  87.— Occlusal  surface  of  the  upper     buccal  while  both    the    lingual 

deciduous  teeth. 

corners  are  much  rounded. 
The  buccal  cusps  are  sharper  than  the  lingual  which  is  full  and 
rounded,  although  all  are  more  pointed  than  those  of  the  upper  per- 
manent molars.  A  central  fossa  occupies  the  space  between  the 
cusps.  It  is  broad  and  shallow.  A  groove  passes  from  it  to  the 
buccal,  mesial  and  distal  sides  respectively,  and  these  serve  to 
separate  the  cusps  from  each  other. 

The  buccal  surface  resembles  that  of  the  upper  molars  except 
that  the  occlusal  margin  is  sharp,  the  surface  is  more  rounded,  the 
buccal  groove  is  very  shallow  and  poorly  defined,  and  at  the  cervical 
margin  a  ridge  of  enamel  passes  from  the  mesial  to  the  distal  border. 
The  lobe  of 'this  surface  mesial  to  the  buccal  groove  is  proportion- 
ately larger  than  that  of  the  permanent  molar,  as  it  is  both  wider  and 
larger  from  occlusal  to  cervical  margin  than  the  distal  lobe. 

The  lingual  surface  is  full  and  convex  in  every  direction  and 
passes  into  the  mesial  and  distal  faces  without  demarcation.  These 
latter  resemble  those  of  the  upper  permanent  molars,  the  mesial  being 
flattened  with  a  convexity  near  the  occlusal  margin,  the  distal  being 
rounded. 


THE    DECIDUOUS    TEETH.  57 

Three  roots  are  possessed  b}'  this  tooth.  They  are  mesio-buccal, 
disto-buccal  and  lingual.  The  buccal  roots  are  flattened  mesio-distally, 
the  lingual  being  flattened  bucco-lingually,  and  they  diverge  mark- 
edly in  order  to  give  a  space  for  the  permanent  tooth  which  succeeds 
and  which  occupies  for  a  time  the  space  between  the  roots. 

The  pulp  chamber  is  rounded  and  large,  corresponding  with  the 
general  external  form  of  the  crown.  The  root  canals  are  small  and 
thread-like  and  difficult  to  enter. 

The  Upper  Second  Molar  (Fig.  89). — This  tooth  is  larger  than 
the  first  temporary  molar  and  resembles  the  first  permanent^molar  so 
exactly  that  a  separate  description  is  unnecessary.     It  seldom  has  the 


Fig.  88. — Skull  showing  deciduous  teeth  in  occlusion. 

lingual  cingule  or  fifth  cusp,  it  is  smaller,  more  constricted  at  the  neck 
and  its  roots  are  widely  separated  at  their  apices,  but  in  other  particu- 
lars the  description  of  the  permanent  tooth  will  suffice. 

The  Lower  Central  Incisor. — Except  for  the  fact  that  the  tooth  is 
smafler,  has  more  rounded  angles,  and  has  its  labial  and  lingual  grooves 
poorly  defined,  the  description  of  the  permanent  tooth  would  equaUy 
apply  to  this.  It  must  be  added,  however,  that  its  root  is  relatively 
smaller  than  that  of  its  successor. 

The  Lower  Lateral  Incisor. — The  resemblance  between  this  and 
the  upper  deciduous  lateral  incisor  is  marked.  It  is  wider  than  the 
lower  central  and  its  distal  angle  is  rounded  like  that  of  the  upper 
lateral.  Its  various  surfaces  and  its  root  are  like  those  of  its  upper 
opponent  and  further  description  is  unnecessary. 


58 


THE    ANATOMY    OF    THE    HUMAN    TEETH. 


The  Lower  Cuspid. — The  upper  and  lower  deciduous  cuspids 
are  much  alike.  The  latter  is  narrower  mesio-distally  and  its  surfaces 
are  not  quite  so  convex  but  in  other  particulars  its  anatomy  is  identical 
with  that  of  the  former. 

The  Lower  First  Molar  (Fig.  89). — This  tooth  has  the  general 
molar  form  but  a  detailed  description  is  necessary  for  its  identifica- 
tion. Its  crown  is  a  much  rounded  cuboid  and  exhibits  four  cusps, 
one  near  each  of  its  rounded  angles.  On  the  occlusal  surface  these 
four  cusps  are  seen  to  be  divided  by  grooves  which  unite  in  the  fossae. 
The  mesio-buccal  cusp  is  the  largest.     A  ridge  descending  from  it 


Fig.  89. — Dissected  specimen  of  maxillae  and  mandible  showing  the  deciduous  teeth. 

anteriorly  curves  and  meets  one  from  the  mesio-lingual  cusp  to  form 
a  mesial  marginal  ridge.  Triangular  ridges  from  these  two  cusps 
meet  at  the  bottom  of  a  mesial  groove,  and  a  small  depression  is  formed 
between  these  and  the  mesial  marginal  ridge.  This  is  often  called 
the  mesial  fossa  but  is  very  small  as  compared  to  the  distal  fossa  which 
is  located  between  the  two  distal  cusps  and  these  triangular  ridges. 
A  distal,  a  buccal  and  a  lingual  groove,  all  poorly  defined,  emanate 
from  the  distal  fossa  in  these  several  directions.  The  buccal  and  lin- 
gual grooves  are  not  continuous  because  the  greater  size  of  the  mesio- 
buccal  cusp  carries  the  former  too  far  distally.  The  disto-buccal 
cusp  is  small,  the  mesio-lingual  is  usually  the  sharpest  and  longest, 
and  the  disto-lingual  is  not  well  defined  as  the  lingual  groove  is  always 
shallow.     The  distal  marginal  ridge  is  cut  by  the  distal  groove. 


THE   DECIDUOUS    TEETH.  59 

The  buccal  surface  is  convex  and  has  near  its  cervical  margin  a 
pronounced  ridge  of  enamel,  the  cervical  ridge.  The  mesial  margin 
is  longer  than  the  distal  in  consequence  of  the  greater  size  and  length 
of  the  mesial  lobe,  a  condition  similar  to  that  of  the  first  upper  decidu- 
ous molar.  The  buccal  groove  is  shallow  and  either  terminates  in 
a  pit  or  disappears  upon  the  center  of  the  surface. 

The  lingual  surface  is  convex,  and  the  lingual  groove  marks  its 
occlusal  portion  about  the  center  when  it  is  present  but  often  it  is 
almost  indistinguishable  on  this  surface.  The  mesial  and  distal  sur- 
faces are  very  similar  to  those  of  the  second  permanent  molar.  The 
mesial  is  fiat  with  a  pronounced  occlusal  edge;  the  distal  is  more 
rounded  and  the  distal  groove  usually  marks  decisively  its  occlusal 
margin.  The  tooth  has  two  roots  which  are  similar  to  those  of  the 
first  permanent  molar  except  that  they  are  smaller  and  quite  divergent 
to  give  space  for  the  bicuspid  which  follows.  The  pulp  chamber  cor- 
responds in  shape  with  the  external  surface  of  the  crown.  The  en- 
trances to  the  three  canals  are  near  together,  the  two  mesial  ones  being 
small  and  very  difficult  to  enter,  the  distal  canal  being  more  accessible. 

The  Lower  Second  Molar  (Fig.  89).— Beside  the  constriction 
of  its  neck,  the  divergence  of  its  roots,  and  its  smaller  size,  this  tooth 
resembles  the  first  permanent  molar  in  almost  every  particular.  The 
description  of  the  latter  tooth  will  apply  to  the  deciduous  tooth  and 
the  reader  is  referred  to  it. 


CHAPTER  11. 
THE  HISTOLOGY  OF  THE  HUMAN  TEETH. 

BY  CHARLES  R.  TURNER,  D.  D.  S.,  M.  D. 

A  knowledge  of  the  minute  anatomy  of  the  tissues  of  the  human 
teeth  is  as  important  as  an  acquaintance  with  their  surface  forms,  for  it 
paves  the  way  to  an  understanding  of  their  several  physiological  rela- 
tionships in  the  tooth,  to  a  knowledge  of  the  pathological  conditions 
arising  in  them,  and  to  a  rational  conception  of  the  various  operative 
and  therapeutic  measures  used  in  the  treatment  of  these  conditions. 

The  tissues  of  the  human  tooth  are  the  enamel,  which  is  the  hard 
external  covering  of  the  crown;  the  dentin,  which  composes  the  bulk  of 
the  tooth  and  largely  determines  its  form;  the  cementum,  which  forms 
the  external  covering  of  the  root  and  to  which  is  attached  the  peri- 
cementum, a  membrane  intervening  between  the  tooth  and  its  bony 
socket  in  the  alveolar  process;  and  finally  the  dental  pulp,  a  mass  of 
soft  tissue  occupying  the  internal  chamber  of  the  tooth  called  the  pulp- 
cavity. 

A  clearer  understanding  of  the  relationships  of  these  tissues  may 
be  had  if  we  first  become  acquainted  with  the  method  of  their  develop- 
ment in  the  embryo.  This  also  confers  a  better  knowledge  of  their 
structure. 

About  the  fortieth  to  the  forty-fifth  day  of  intra-uterine  life,  there 
is  a  thickening  of  the  stratum  Malpighii  of  the  oral  epithelium  over  the 
site  of  the  future  jaw.  This  forms  a  band  of  epithelial  cells  extending 
from  one  end  to  the  other  in  each  jaw.  About  the  forty-eighth  day  a 
budding  is  seen  to  take  place  from  the  under  surface  of  this  tooth-band, 
and  ten  rounded  buds  appear  attached  to  it,  marking  the  beginning  of 
the  tooth-germs  for  the  deciduous  teeth.  These  buds  dip  further  into 
the  substance  of  the  underlying  connective  tissue,  and  becoming  invagin- 
ated  upon  their  advancing  surfaces,  finally  enclose  in  this  invagina- 
tion a  mass  of  mesoblastic  connective  tissue  and  become  the  tooth- 
germs.  This  epithelial  cup  which  has  descended  from  the  mucous 
membrane  remains  connected  with  it  for  some  time  by  a  cord  of  epithe- 
lial cells,  the  epithelial  cord,  but  this  cord  soon  disappears,  and  the 
tooth-germ  is  enclosed  by  a  fibrous  membrane  developed  from  the 

60 


THE    ENAMEL. 


6i 


surrounding  tissue.  The  epithelial  cup  becomes  the  enamel  organ  of 
the  future  tooth,  the  connective  tissue  enclosed  by  it  becomes  the  dentin 
organ  or  papilla.  The  whole  tooth-germ  enclosed  in  its  sac  is  known 
as  the  dental  follicle.     (Fig  90.) 

The  enamel  organ  takes  on  the  form  peculiar  to  the  tooth  which  it  is 
to  assist  in  forming,  and  its  cells  begin  to  alter  in  character.     Those 


biG.  90. — Section  of  upper  jaw  of  human  embryo  near  the  seventh  month  of  fetal 
life,  showing  development  of  temporary  cuspid.  A.  Ameloblasts  showing  beginning  of 
enamel  formation.  B.  Dentin.  C.  Showing  beginning  of  dentin  formation.  D.  Walls 
of  tooth  sac.     E.  Dentinal  papilla.     X  So-     (Williams.     Dental  Cosmos.) 


next  to  the  dentinal  papilla  become  columnar  in  form,  those  on  the  ex- 
terior disappear  by  atrophy,  while  the  intervening  ones  are  changed 
from  polygonal  to  stellate  cells  and  become  the  stellate  reticulum. 
This  latter  finally  almost  entirely  disappears,  leaving  however  next  to 
the  inner  columnar  layer  a  small  layer  of  cells  which  now  comes  to  be 
known  as  the  stratum  intermedium.  The  inner  columnar  cells  now 
become  enlarged  and  elongated,  their  nuclei  move  to  their  outer  ends 


62  THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 

and  they  become  the  ameloblasts,  which  are  the  cells  directly  concerned 
with  the  formation  of  the  enamel. 

The  dentin  organ  or  papilla  which  occupies  the  space  within 
the  enamel  organ,  and  which  is  formed  from  the  mesoblastic  con- 
nective tissue,  is  composed  of  embryonal  connective  tissue  cells  of 
various  kinds;  spindle  shaped,  round,  and  stellate  cells  are  scattered 
through  its  substance,  while  over  its  entire  periphery  there  is  a  layer  of 
specialized  club-shaped  cells,  the  odontoblasts,  which  are  specifically 
concerned  in  the  formation  of  the  dentin. 

In  the  development  of  the  tooth,  a  deposit  of  dentin  initiates  the 
process,  a  layer  of  dentin  being  calcified  about  the  external  surface  of 
the  odontoblastic  layer  of  the  papilla.  The  function  of  the  odontoblasts 
in  this  process  is  imperfectly  made  out.  It  is  known  that  lime  salts 
are  deposited  about  their  external  processes  and  that  these  latter 
become  the  dentinal  fibrils.  Furthermore,  as  said  by  Broomell,  they  are 
believed  to  superintend  the  dentin  formation,  but  just  what  is  their  rela- 
tion to  the  deposition  of  the  lime  salts  is  not  known.  After  the  dentin 
cap  is  begun  it  grows  by  additions  to  its  interior,  while  upon  its 
periphery  enamel  formation  begins.  This  is  by  a  process  of  secretion  in 
which  globular  masses  of  calco-globulin  are  formed  in  the  ameloblas- 
tic cells;  these  escape  from  the  external  ends  of  the  ameloblasts  and, 
becoming  packed  together  one  after  another,  form  the  enamel  prisms. 
An  albumen-like  substance,  according  to  Williams,  is  secreted  in  the 
stratum  intermedium,  and  flows  about  the  partially  formed  prisms, 
"  supplying  the  cement  substance  and  probably  the  mineral  matter  for 
the  calcification  of  the  whole." 

Cementum  is  formed  upon  the  completed  dentin  root  of  the  tooth 
by  specialized  odontoblastic  cells,  the  cementoblasis,  which  have  devel- 
oped in  the  wall  of  the  tooth  follicle.  Its  growth  is  similar  to  that  of 
subperiosteal  bone. 

The  pulp  is  what  remains  of  the  dentin  papilla,  after  the  latter  has 
been  reduced  in  size  by  the  growth  of  the  dentin  walls.  The  periph- 
eral layer  of  odontoblasts  persists  during  the  life  of  the  pulp,  but 
after  the  mature  tooth  is  formed,  these  cells  remain  inactive  unless 
called  into  activity  by  some  pathologic  stimulation  from  without. 

THE  ENAMEL. 

The  enamel  constitutes  the  external  covering  of  the  crowns  of 
the  teeth.  It  is  by  far  the  hardest  of  the  animal  tissues  and  for  this 
reason  it  is  particularly  suited  to  resist  the  wear  incident  to  the  use  of 
the  teeth  in  the  comminution  of  food.     Its  distribution  over  the  crown 


THE   ENAMEL.  63 

of  a  tooth  is  not  uniform,  as  it  is  thinnest  at  the  cervical  margin,  where 
it  is  slightly  overlapped  by  the  cementum;  from  this  margin  it  increases 
in  thickness,  until  over  the  cusps  and  cutting  edges  of  the  teeth,  where 
it  is  most  exposed  to  wear,  it  is  thickest  of  all.  It  is  also  slightly 
thicker  at  the  site  of  the  elevations  and  ridges  upon  the  crowns  of  the 
teeth.  In  the  newly  erupted  tooth  it  is  faintly  and  dehcately  ridged 
transversely,  and  in  some  teeth  it  presents  other  evidences  of  its  develop- 
ment, but  it  soon  wears  smooth  and  lustrous.  When  a  tooth  is  erupted 
the  enamel  is  entirely  completed  over  the  whole  of  its  crown.  No 
portion  of  the  tooth  is  erupted  until  the  enamel  covering  it  is  fully 
formed.  When  once  formed  enamel  is  a  fully  completed  substance, 
and  no  physiologic  change  in  its  structure  or  composition  ever  occurs 
thereafter.  Williams  remarks,  "Enamel  is  a  solid  mineral  substance, 
and  the  finest  lenses  reveal  not  the  slightest  differences  between  enamel 
ground  moist  from  a  living  tooth,  and  that  which  has  laid  in  the  earth 
for  a  hundred  centuries." 

Defects  in  the  structure  of  the  enamel,  in  consequence  of  which  the 
value  of  its  protective  office  is  lessened,  are  commonly  observed  at  the 
site  of  the  fissures  and  pits  upon  the  surface  of  the  tooth-crown  which 
marks  the  points  of  union  of  the  several  centers  from  which  calcification 
began.  These  faults  are  frequently  found  in  the  sulci  of  the  molar  and 
bicuspid  teeth,  in  the  buccal  pits  of  the  molar  teeth,  and  in  the 
lingual  fossae  of  the  upper  lateral  incisors.  These  defects  are  favor- 
able sites  for  the  beginning  of  caries,  the  break  in  the  integrity  of 
the  enamel  affording  lodgment  for  the  bacteria  and  a  favorable 
starting  point  for  their  activity. 

While  enamel  is  formed  in  an  organic  matrix,  not  the  least  trace 
of  this  remains  chemically  in  the  completed  enamel.  This  accounts 
for  the  lack  of  sensitivity  of  this  structure,  for  it  is  not  capable  of  trans- 
mitting physiologically  any  sensations  whatever.  These  facts  demon- 
strate its  value  as  a  vital  protective  covering  for  the  teeth. 

Chemically  it  consists  chiefly  of  the  phosphate  and  carbonate  of 
calcium  as  the  following  analysis  by  von  Bibra  shows: 

Man.  Woman. 

Calcium  phosphate  and  fluorid, 89.82  81.63 

Calcium  carbonate, 4-37  ^-^^ 

Magnesium  phosphate, 1.34  3-55 

Other  salts 88  .97 

Cartilage, 3-39  5-97 

Fat,    20  a  trace 

Organic, 3  59  5-97 

Inorganic 96.41  94-o3 


64  THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 

Charles  Tomes  has  shown  that  the  organic  matter  obtained  in  this 
and  the  older  analyses  is  simply  the  water  which  is  combined  with 
the  lime  salts.  He  has  proven  that  it  will  be  suddenly  given  off  upon 
ignition  of  the  specimen  under  analysis. 

Enamel  is  not  a  homogeneous  mass  of  calcified  tissue  but,  under 
the  microscope  may  be  seen  to  consist  of  a  collection  of  prisms  or  rods, 


Fig. ""9 1. — Section  of  enamel  of  human  tooth  near  line  of  dentin.     Shows  enamel  rods  in 
cross-  and  longitudinal  section.     X  1000.     (Williams.     Dental  Cosmos.) 

five  and  six  sided,  which  are  united  together  by  means  of  a  cementing 
substance.  (Fig.  91.)  As  it  contains  no  organic  matter  whatever  and 
has  resulted  from  the  completed  calcification  of  the  matrix  in  which 
it  is  formed,  we  find  no  chemical  remains  of  the  matrix,  but  the  tissue 
exhibits  structural  evidences  of  its  mode  of  formation.  Generally 
speaking  the  enamel  rods  are  arranged  so  that  they  begin  at  right  angles 
to  the  surface  of  the  dentin,  from  which  they  extend  to  the  external 
surface  of  the  tooth.     In  the  cervical  region  they  incline  somewhat 


THE    ENAMEL. 


65 


downward  in  the  direction  of  the  root,  but  as  the  lower  third  of  the 
crown  is  reached  they  pass  horizontally  outward,  becoming  more  in- 
clined occlusally  as  the  cusps  and  the  cutting  edges  of  the  teeth  are 
reached,  in  which  positions  they  are  largely  parallel  to  the  long  axis 
of  the  tooth.  (Fig.  92.)  The  ends  of  the  prisms  are  thus  exposed  to 
the  wear  of  these  surfaces. 

While  a  majority  of  the  rods  extend  from  dentin  to  surface,  it  will 
be  seen  that  as  the  surface  area  of  the  latter  is  greater  than  that  of  the 
former,  and  as  the  rods  are  practically  of  the  same  diameter  at  each  end, 


Dentin. 


Enamel 


Fig.  92. — Section  showing  dentino-enamel  juncture,  the  direction  of  the  enamel  rods 
and  primary  curvatures  of  dentinal  tubules.     (Broomell.) 

additional  rods  are  required  to  fill  in  the  interspaces  in  this  fan-like 
arrangement.  These  additional  rods  begin  between  the  other  long 
rods  and  extend  outward  toward  the  surface  of  the  tooth.  While  the 
rods  pursue  in  general  an  almost  straight  course,  in  all  instances 
they  are  slightly  curved  and  in  some  cases  they  are  much  contorted  and 
twisted,  and  when  this  is  marked  the  enamel  is  usually  spoken  of  as 
"gnarled." 

The  rods  are  not  of  uniform  diameter  throughout  their  whole  ex- 
tent, as  each  rod  presents  a  number  of  varicosities  which  increase  its 
size.  (Fig.  93.)  These  varicosities  vary  in  different  specimens  of  en- 
amel but  they  are  present  in  all.  The  enlarged  portion  of  one  rod  is 
opposite  to  that  of  the  adjacent  rods,  and  they  do  not  alternate  as 

5 


66  THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 

would  seem  the  more  natural  arrangement.  The  reason  for  this  is 
the  fact  that  the  globules,  of  which  the  rods  are  made  and  which  are 
responsible  for  the  varicosities,  were  deposited  simultaneously.  The 
varicosities  do  not  as  a  rule  appear  so  pronounced  in  the  enamel  next 
the  dentin,  but  elsewhere  in  any  given  specimen  they  are  of  about  uni- 
form occurrence.  The  space  between  the  rods  is  filled  in  with  a  more 
transparent  but  not  more  highly  calcified  cement  substance.  Wil- 
liams has  shown  a  specimen  in  which  the  globules  composing  the  rods 
do  not  appear  continuous  but  seem  united  with  this  cement  substance 
as  the  rods  are  united  to  each  other.     It  is  very  probable  that  this  is 


Fig.  93. — Enamel  rods  showing  varicosities  and  striie  of  Retzius.  A.  Brown  striae 
of  Retzius.     B.  Enamel  rods  showing  varicosities.     X  200.    (Williams.    Dental  Cosmos.^ 

due  to  the  refraction  of  the  light  by  the  rod  substance,  as  longitudinal 
sections  of  the  rods  normally  exhibit  under  the  microscope  a  series  of 
light  bands,  the  so-called  "  striation"  of  the  rods,  which  may  be  brought 
into  view  or  made  to  disappear  by  slightly  changing  the  focus  and 
were  formerly  believed  to  have  some  structural  significance. 

Another  appearance  presented  by  the  enamel  rods  under  the  micro- 
scope is  illustrated  in  Fig.  94.  In  this  it  will  be  seen  that  bands  of 
darker  enamel  alternate  with  those  of  lighter,  thus  dividing  it  into  strata. 
This  stratification  of  the  enamel  is  due  to  the  fact  that  small  quantities 
of  pigment  have  been  laid  dov^^n  at  various  stages  in  its  development, 
and  they  simply  mark  the  exterior  of  the  crown  at  the  time  they  were 
laid  down.  They  are  in  reality  incremental  lines  and  mark  successive 
stages  in  the  growth  of  the  enamel.     They  are  usually  spoken  of  as  the 


THE    ENAMEL. 


67 


"brown  striae  of  Retzius. "  They  begin  at  the  summit  of  the  already 
formed  dentin  and  extend  in  curves  toward  the  cervix.  The  addition 
of  more  dentin  at  the  developing  end  of  the  tooth  gives  more  surface 
for  enamel  to  be  deposited  upon,  and  another  stratum  of  enamel  is 
formed  covering  the  already  formed  enamel.  The  enamel  formation 
at  the  occlusal  end  of  the  crown  is  completed  before  that  at  the  cervix. 


Fig.  94. — Longitudinal  section  of  human  enamel  showing  globules, 
light.     X  3°°-     (Williams.     Dental  Cosmos.) 


Polarized 


These  facts  explain  why  the  incremental  lines  are  neither  parallel  to 
the  external  surface  nor  to  that  of  the  dentin. 

The  "lines  of  Schreger"  are  another  characteristic  of  fully  formed 
enamel.  They  are  not  visible  by  transmitted  light  but  can  be  seen  by 
reflected  light  as  Fig.  95  shows.  They  are  said  to  be  due  "  to  the  various 
directions  assumed  by  the  contiguous  groups  of  enamel  rods. "  * 

The  physical  characters  of  enamel,  which  are  interesting  from 

♦Broomell:     Anatomy  and  Histology  of  Mouth  and  Teeth,  1902,  p.  395. 


68 


THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 


the  Standpoint  of  filling  operations  upon  the  teeth,  are  more  readily  un- 
derstood when  they  are  viewed  in  the  light  of  the  histology  of  the  tissue. 
Mature  enamel  forms  a  hard  covering  for  the  crowns  of  the  teeth 
which  will  resist  a  large  amount  of  force  upon  it.  The  enamel  rods  fit 
closely  together  and  the  intervening  tissue  is  highly  calcified  and  binds 
them  together.  Thus  they  give  each  other  lateral  support,  and  unless 
there  is  a  break  in  the  enamel  surface,  it  is  very  difficult  to  fracture  or 
crush  them.  In  addition,  their  inner  ends  rest  upon  the  dentin,  a 
slightly  elastic  tissue,  which  gives  them  a  firm  support.  It  is  upon 
these  two  facts  that  the  ability  of  the  enamel  to  resist  physical  force 


"'    ^^> 

/         ,^  --'^ 

V^ 

-J^^^ 

mk. 

Srownjstria; 
of  Retzius. 

^H^ 

W  '■Ik^ 

':^^^^H    ' 

Lines  of   f 
Schreger.  1 

^^^m 

w 

^^^M 

^ 

Enamel. 


Dentin. 


Fig.  95. — Section  showing  striae  of  Retzius  or  incremental  lines  of  the  enamel 
and  the  lines  of  Schreger.      (Gysi.     Broomell.) 


largely  rests.  If,  however,  there  is  a  break  in  the  enamel  surface,  then 
it  is  an  easy  matter  to  split  off  the  enamel  rods  immediately  adjacent  to 
the  break,  and  especially  is  this  true  if  the  enamel  so  split  is  not  sup- 
ported upon  mechanically  sound  dentin.  While  the  enamel  is  intrin- 
sically of  a  high  degree  of  hardness,  yet  it  has  a  natural  cleavage, 
and  the  line  of  this  is  along  the  interprismatic  substance,  so  that  the 
line  of  cleavage  is  approximately  parallel  to  the  direction  of  the  prisms. 
Occasionally  it  breaks  transversely  through  a  prism  here  and  there, 
but  never  along  the  central  axis  of  the  prism.  The  lesson  these  facts 
teach  in  the  preparation  of  cavities  for  filling  operations  is  that  the  en- 
amel at  their  margins  must  be  supported  upon  dentin,  and  that  these 


THE    DENTIN.  69 

margins  must  be  formed  so  that  no  prisms  which  do  not  reach  the 
dentin  are  allowed  to  remain.  This  requires  that  the  cavity  margins  be 
beveled  at  the  expense  of  prisms  which  are  firmly  seated  upon  the  den- 
tin, and  a  knowledge  of  the  direction  of  the  enamel  prisms  is  neces- 
sary in  preparing  the  cavity  margins. 

Black*  has  shown  that  enamel  possesses  less  strength  than  the 
dentin,  as  to  resistance  to  both  tensile  and  crushing  strains.  Therefore 
the  retentive  portions  of  cavities  should  be  made  in  the  dentin,  and  the 
mechanical  force  used  in  the  insertion  of  gold  fillings  should  be  slight 
upon  enamel  margins.  He  has  also  shown  that  where  several  thick- 
nesses of  gold  were  placed  between  the  instrument  and  the  enamel, 
that  the  crushing  effect  of  impact  is  greatly  reduced. 

THE  DENTIN. 

The  dentin  composes  the  bulk  of  the  tooth,  and  contributes  to  its 
form  and  strengT;h.  It  surrounds  the  pulp  and  protects  this  from  injury, 
it  gives  support  to  the  enamel  covering  the  crown,  and  upon  its  root  por- 
tion is  deposited  the  cementum  which  affords  attachment  to  the  retentive 
tissues  of  the  tooth.  Normally  no  part  of  it  appears  upon  the  external 
surface  of  the  tooth,  and  when  here  present  is  exposed  from  some  error 
in  the  development  of  the  tooth  or  from  some  break  in  the  enamel  or 
cementum.  It  is  light  yellow  in  color,  although  it  varies  slightly  in 
shade  in  different  specimens,  and  it  has  somewhat  the  appearance  of 
ivory  or  bone. 

Histologically  it  is  a  highly  developed  connective  tissue,  and  con- 
sists of  a  partly  calcified  organic  matrix  traversed  by  a  system  of  tubules, 
the  contents  of  which  is  protoplasmic  in  character.  As  it  is  impossible 
to  remove  the  contents  of  the  tubules  no  chemical  analysis  has  been 
obtained  of  the  matrix  proper.  Von  Bibra  gives  the  following  as  the 
constituents  of  a  specimen  of  thoroughly  dried  dentin: 

Organic  matter  (tooth  cartilage) 27.61 

Fat, 0.40 

Calcium  phosphate  and  fluorid, 66.72 

Calcium  carbonate, 3.36 

Magnesium  phosphate, 1.08 

Other  salts 0.83 

When  the  tissue  is  decalcified  by  the  use  of  strong  acids,  the  re- 
maining organic  matrix  yields  gelatin  on  boiling,  while  that  portion 
immediately  surrounding  the  tubules  which  differs  from  the  body  of  the 
matrix  in  resisting  strong  acids  and  alkalies,  yields  elastin  on  boiling 

*The  Dental  Cosmos,  Vol.  xxxvii,  page  414. 


70 


THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 


(Noyes).  Opinion  differs  as  to  whether  this  is  more  highly  calcified 
than  the  surrounding  matrix.  Under  the  microscope  it  has  a  dififerent 
refractive  action  upon  light  as  the  accompanying  high-power  field  shows 
(Fig.  96).  These  are  known  as  "//zg  sheaths  0}  Neumann,"  and  sur- 
round the  protoplasmic  contents  of  the  tubules. 

The  matrix  itself  is  practically  structureless  and  homogeneous 
in  character.  The  tubules  traverse  it  from  the  pulp-cavity,  to  the 
external  surface  of  the  dentin.  (Fig.  97.)  They  begin  by  a  funnel-like 
opening  in  the  pulp-cavity  wall,  and  extend  in  curves  outward  to  near 
the  surface  of  the  dentin  where  they  usually  branch  and  anastomose 
freely.     They  are  of  practically  uniform  caliber  from  beginning  to  end, 


Fig.  96. — Dentin  showing  tubules  in  cross-section.  Dt. 
Dentin  matrix.  S.  Shadows  of  sheaths  of  Neumann.  (Noyes. 
Operative  Dentistry.) 


Dentinal  tubules.     D. 
American  Text-hook  of 


and  as  the  external  surface-area  of  the  dentin  is  greater  than  that  at  the 
pulp-cavity,  the  tubules  are  closer  together  at  their  beginning  from  the 
latter  than  at  the  external  surface,  and  diverge  almost  imperceptibly  in 
passing  outward.  They  exhibit  long  graceful  curves  in  their  course 
outward.  In  the  crown  of  the  tooth  the  tubules  exhibit  what  have  been 
designated  their  primary  and  secondary  curvatures.  The  tubules  be- 
gin at  right  angles  to  the  surface  of  the  pulp,  and  reach  the  surface 
of  the  enamel  at  a  right  angle  to  it.  Between  these  points  they  present 
a  reversed  curve  or  ogee.  The  secondary  curvatures  are  perceptible 
throughout  the  extent  of  the  tubule  and  are  due  to  the  fact  that  the 
tubule  has  a  general  spiral  direction  through  the  dentin.     In  the  root 


THE    DENTIN.  7 1 

portions  of  the  teeth  the  tubules  pursue  almost  a  straight  course  from 
the  pulp  to  cementum,  which  in  general  is  perpendicular  to  the  long 
axis  of  the  tooth.  In  the  apical  region  they  are  arranged  radially. 
At  or  near  the  external  end  they  branch  out  and  anastomose  freely. 
Inasmuch  as  it  is  along  the  line  of  the  tubules  that  the  infection  travels 
in  caries,  this  arrangement  explains  how  caries  may  progress  along  the 
dentino-enamel  juncture  and  how  the  enamel  is  undermined.  This 
also  explains  the  greater  sensitivity  of  the  tooth  at  the  dentino- 
enamel  juncture,  a  clinical  fact  of  common  knowledge. 

The  dentinal  tubules  contain  a  protoplasmic  mass,  the  dentinal 
fibrils,  which  extend  from  the  odontoblastic  layer  of  cells  on  the  ex- 


X 


Fig.  97. — Transverse  section  through  root  of  human  molar  showing  the  curvature  of 
the  dentinal  tubules  about  the  pulp  canal.     X  4°-     (Broomell.) 

ternal  surface  of  the  pulp.  These  are  usually  called  the  fibers  of 
Tomes.  Beyond  the  fact  that  the  fibrils  are  processes  of  the  odonto- 
blastic cells,  nothing  yet  is  definitely  known  about  the  manner  of  their 
connection  with  the  nerves  of  the  pulp,  nor  about  the  way  in  which 
sensory  impulses  are  transmitted  by  them.  Unlike  the  enamel  the 
dentin  is  a  sensitive  tissue  and  has  physiologic  connection  with  the 
organism.  The  dentinal  fibrils  conduct  sensory  impulses  and  it  is 
believed  that  in  some  way  the  dentin  is  nourished  through  the  con- 
tents of  the  tubuli.  One  reason  for  a  belief  in  the  latter  is  the  fact  as 
brought  out  by  Black  that  the  dentin  of  old  teeth  has  a  higher  percentage 


72 


THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 


of  lime  salts  than  that  of  young  teeth.  The  growth  of  the  dentin  is  not 
completed  with  the  eruption  of  the  tooth,  for  all  of  its  root  is  not 
formed  at  this  period,  but  continues  for  some  time  afterward.  The 
root  is  completed  and  the  pulp  becomes  reduced  in  size,  successive 
layers  of  dentin  encroaching  on  the  pulp-cavity.  In  the  mature 
tooth  the  process  of  dentin  formation  remains  at  a  standstill  until 
old  age,  when  it  will  be  found  that  the  pulp-cavities  are  reduced  to 
very  small  dimensions. 

The  odontoblasts  may  be  stimulated  into  activity  by  irritation  from 
the  encroachments  of  carious  cavities  or  by  a  wearing  away  of  the 


Cementum. 


Granular 
layer. 


A 

^ 

o 

wl 

%^> 

r 

* 

r 

^ 

i»- 

Dentin. 


Fig.  98. — Interglobular  spaces  in  the  dentin.     X  60.     (Broomell.     Dental  Cosmos.) 


tooth  substance  from  abrasion  or  erosion.  Dentin  is  deposited  on  the 
pulp-cavity  wall  immediately  in  relation  with  the  site  of  the  irritation 
and  is  an  expression  of  a  self-protective  activity  of  the  pulp.  Dentin 
thus  deposited  is  known  as  secondary  dentin.  It  is  of  poorer  structure 
than  normal  dentin  and  not  typical  in  the  arrangement  of  its  tubules, 
which  present  many  interruptions. 

At  the  dentino-cemental  juncture  the  dentin  presents  under  the 
low  powers  a  somewhat  granular  appearance,  and  this  area  is  known 
as  the  granular  layer  of  Tomes.  (Fig.  98.)  It  consists  of  the  so-called 
interglobular  spaces,  which  are  erroneously  so  named  as  in  the  fresh 


THE    CEMENTUM.  73 

specimen  they  are  not  spaces  but  are  areas  of  imperfectly  calcified  dentin. 
They  are  filled  with  protoplasmic  tissue  through  which  the  dentinal 
fibrils  may  be  made  out.  In  the  dried  specimen  they  appear  as  spaces 
because  of  the  desiccation  and  contraction  of  their  protoplasmic  con- 
tents. These  so-called  interglobular  spaces  are  often  found  else- 
where scattered  through  the  dentin,  usually  occupying  positions  cor- 
responding to  a  stage  in  the  development  of  the  dentin. 

THE  CEMENTUM. 

Histologically  considered  cementum  is  very  closely  related  to  sub- 
periosteal bone  both  in  its  structure  and  development.  It  forms  the 
external  covering  of  the  roots  of  the  teeth,  serving  as  a  medium  of  at- 
tachment between  the  pericementum  and  the  dentin.     At  the  cervical 


Fig.  99. — Cementum  from  cervix  of  adult  tooth.     X  4°-     (Broomell.) 

margin,  it  abuts  upon  tlxj  edge  of  the  enamel  or  slightly  overlaps  it 
and  at  this  point  is  thinly  distributed  over  the  surface  of  the  root.  It 
increases  in  thickness  as  the  apex  of  the  root  is  reached  and  the  mature 
tooth  is  of  considerable  thickness  in  this  region. 

While  its  structure  resembles  that  of  bone  in  many  particulars 
it  differs  in  having  no  Haversian  system  and  is  easily  distinguished 
from  it  under  the  microscope.  It  presents  for  examination  a  matrix 
of  partially  calcified  organic  material  containing  lacuncB  and  canalic- 


74  THE    HISTOLOGY    OF    THE    HUMAN   TEETH. 

uli.  The  matrix  or  ground-substance  is  similar  in  structure  and  com- 
position to  that  of  bone.  The  lacunse  are  spaces  scattered  through 
the  matrix  which  are  occupied  in  the  recent  specimen  by  the  cement 
corpuscles,  which  are  cement-forming  cells  or  cementoblasts  which 
have  become  encapsulated  during  the  calcification  of  the  tissue.  The 
canaliculi  extend  from  the  lacunse  and  transmit  the  processes  of  the 
cement  corpuscles.  Beside  these  elements  the  tissue  contains  the 
cement  fibers  which  are  calcified  fibers  of  the  pericementum.  It  is 
developed  by  the  deposit  of  successive  lamellae  upon  the  dentin  surface 
and  these  are  visible  under  the  microscope  as  its  incremental  lines. 


Fig.  ioo. — Cement  corpuscles  of  the  outer  strata.     X  40.     (Broomell.) 

The  character  of  the  tissue  varies  with  its  position  upon  the  root  and 
with  the  period  of  tooth  development  at  which  it  is  formed. 

The  matrix  next  to  the  dentin  is  more  nearly  homogeneous  than 
elsewhere.  Under  the  microscope  it  appears  somewhat  granular 
and  is  characterized  by  the  absence  of  lacunse  and  canaliculi.  (Fig  99.) 
This  is  also  largely  true  of  the  whole  thickness  of  the  cementum  near 
the  cervical  margin  as  lacunae  are  infrequent  there.  The  lamellae  making 
the  successive  additions  to  the  tissue  increase  both  in  number  and  thick- 
ness as  the  apex  of  the  tooth  is  approached,  and  the  lacunae  become 
more  abundant  in  them. 

The  cement  corpuscles  which  occupy  the  lacunae  are  masses  of 
protoplasmic  tissue  which  are  the  remains  of  cementoblasts.     They 


THE    CEMENTUM.  75 

are  most  abundant  in  the  middle  layers  of  the  cementum,  are  absent 
in  the  portion  next  the  dentin,  and  are  infrequent  in  the  outermost 
layers.  (Fig.  loo.)  Their  processes  are  usually  directed  toward  the 
outer  surface  of  the  tooth,  and  these  occupy  the  canaliculi  above  re- 
ferred to. 

Another  element  of  the  cementum  which  is  the  most  variable  of  its 
histological  constituents  is  the  cement  fibers.  (Fig.  loi.)  These, 
according  to  Black,  are  principal  fibers  of  the  pericementum  which 
have  been  caught  in  the  developing  tissue  and  calcified.  In  some 
rare  instances  they  may  be  observed  to  extend  from  the  innermost 


/ 


\ 


Fig.  ioi. — Cemenlal  fibers  of  die  middle  strata.      X  60. 
(Broomell.      Dental  Cosmos.) 

layer  uninterruptedly  through  to  the  surface,  but  they  are  usually  of 
much  shorter  extent.  Sometimes  they  correspond  in  length  only  to 
the  thickness  of  one  lamella  and  sometimes  to  that  of  two  or  more. 
This  variation  is  due  to  the  manner  of  growth  of  the  cementum  and 
to  the  fact  that  the  attachment  of  the  pericementum  is  constantly 
varying,  the  fibers  being  frequently  cut  off  and  reattached  at  different 
positions.  Thus  the  cement  fibers  which  terminate  at  the  surface 
of  a  lamella  are  those  whose  attachment  has  been  altered  at  the  com- 
pletion of  the  lamella.  The  fibers  are  of  most  frequent  occurrence  in 
the  apical  two-thirds  of  the  tissue  and  in  the  central  strata  of  this  re- 


76  THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 

gion.  Broomell  has  called  attention  to  the  presence  of  fibers  in  bun- 
dles in  the  oldest  lamella,  the  bundles  being  arranged  radially  to  the  long 
axis  of  the  tooth.  The  fibers  which  extend  from  the  dentin  do  not 
have  any  direct  connection  with  it,  but  usually  terminate  here  by  break- 
ing up  into  fibers  which  run  more  or  less  parallel  to  its  outer  surface. 
This  is  to  be  expected  when  the  method  of  cemental  development  is 
remembered. 

In  some  of  the  multi-rooted  teeth  the  cementum  bridges  over  the 
gap  from  one  root  to  the  other,  building  in  the  space  solidly.  Usually 
some  evidence  in  the  way  of  cement  cells  or  mesoblastic  tissue  remains 
to  show  where  the  extensions  from  each  root  have  united.  In  this 
type  of  tissue  the  lamellae  are  poorly  marked. 

The  formation  of  cementum  goes  on  more  or  less  constantly 
during  life,  as  cementoblasts  are  constantly  present  in  the  perice- 
mentum next  to  the  tooth.  In  youth  the  cementum  is  thin  as  com- 
pared to  that  found  in  adult  life  and  iii  old  age. 

The  cementoblasts  are  sometimes  called  into  activity  after  the  tooth 
is  formed  by  some  pathological  excitant,  and  this  condition  is  known 
as  a  hyper-cementosis  of  the  tooth.  The  tissue  thus  formed  may  be 
of  such  extent  as  to  complicate  the  extraction  of  the  tooth,  or  it  may 
press  upon  the  nerves  leading  to  the  pulp  or  to  that  of  some  other  tooth 
and  cause  obscure  pains  which  are  difficult  to  recognize  clinically.  The 
pathologic  cementum  is  usually  upon  the  apical  portion  of  the  tooth, 
and  is  not  typical  histologically. 

Union  occasionally  occurs  between  the  roots  of  different  teeth  by  a 
fusion  of  the  cementum  in  a  manner  somewhat  similar  to  that  in  which 
the  roots  of  a  tooth  unite.  This  gives  rise  to  the  so-called  fused  teeth 
which  are  occasionally  found. 

THE  PULP. 

The  dental  pulp  consists  of  the  soft  tissues  occupying  the  central 
cavity  of  the  tooth  known  as  the  pulp-cavity.  It  is  the  somewhat 
changed  remains  of  the  dental  papilla,  the  formative  organ  of  the  den- 
tin. It  is  composed  of  soft  embryonal  connective  tissue,  odontoblastic 
cells,  blood  vessels,  and  nerves.  No  lymphatics  exist  in  the  pulp — a 
fact  of  pathologic  interest.  It  has  two  functions,  the  formation  of  the 
dentin,  a  function  practically  quiescent  in  the  adult  tooth,  and  the 
nutrition  and  innervation  of  the  dentin. 

The  odontoblasts,  through  the  medium  of  which  the  dentin  is  formed , 
are  a  layer  of  cells  occupying  the  entire  periphery  of  the  pulp  and  in 
close  relation  with  the  dentin.     (Fig.  102.)    They  exist  as  a  single  layer 


THE    PULP. 


77 


of  cylindrical  cells  during  the  formative  period  of  the  tooth  and  until 
late  life,  when  they  become  rounded  or  spheroid.  They  possess  three 
kinds  of  processes  which  are  usually  referred  to  as  dentinal,  lateral,  and 
pulpal.  The  dentinal  processes,  of  which  there  is  only  one  to  an  odon- 
toblast (occasionally  two  may  be  found),  are  the  dentinal  fibrils  or 
fibers  of  Tomes  which  enter  the  dentinal  tubules;  the  lateral  processes 


:'  '~-■-^'-;"^v'- 


.  n  :  ■■  •' 


.  '   *,,%;  "-^v 


Fig.  102. — Section  of  developing  L^^wiii  ^^i  ii^^Liian  embryo  near  seventh  month  of 
fetal  life.  F.  Ameloblasts.  H.  Dentin.  I.  Odontoblasts.  B.  and  C.  Cells  of  reticulum 
of  enamel  organ.     D.  Stratum  intermedium.     X  i7S-     (Williams.     Dental  Cosmos.) 


are  numerous  and  by  this  means  the  odontoblasts  are  connected  to 
each  other;  the  pulpal  processes  extend  into  the  "layer  of  Weil," 
a  transparent  layer  of  tissue  in  relation  with  the  pulpal  ends  of  the 
odontoblasts,  and  there  become  lost  to  view.  The  odontoblastic 
cells  have  large,  oval,  deep-staining  nuclei  situated  near  the  pulpal  ex- 
tremity of  the  cells.  This  layer  of  odontoblasts  is  often  called  the 
memhrana  eboris. 


78 


THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 


The  layer  of  Weil,  situated  just  below  the  odontoblasts,  is  a  trans- 
parent layer  of  tissue  containing  very  few  connective  tissue  cells,  and 
then  below  this  comes  the  main  body  of  the  pulp  tissue.  (Fig.  103.) 
This  is  composed  of  connective  tissue  cells,  which  may  be  either  stel- 
late or  spindle-shaped,  with  a  large  mass  of  intercellular  substance, 


•'-     N 


:*»     kv'xWs  .< 


Fig.  103. — Section  of  developing  tooth  of  embryo  calf.  A.  Stellate  reticulum.  B. 
Stratum  intermedium.  C.  Ameloblasts.  D.  Dentin.  E.  Odontoblasts.  F.  Blood 
vessels  with  corpuscles  in  situ.     X  275.     (Williams.     Dental  Cosmos.) 


together  with  a  few  round  cells  which  Noyes  says  "are  probably  young 
cells  which  have  not  yet  acquired  the  adult  form." 

The  blood  vessels  of  the  pulp  communicate  with  the  general  cir- 
culation through  the  apical  foramen  or  foramina  of  the  tooth.  One 
or  more  small  arterial  trunks  enter  the  pulp-cavity  at  the  apex  and, 
coursing  occlusally  through  the  center  of  the  tissue,  give  off  many 
branches.  Near  the  occlusal  end  of  the  pulp  they  further  divide  into 
capillaries  and  form  a  fine  plexus  around  the  peripheral  portion  of  the 
pulp.     The  blood  vessels  are  generously  distributed  through  the  tissue. 


THE    PULP.  79 

The  veins  form  a  similar  plexus  and  a  central  vein  analogous  to  the 
artery  receives  the  blood  from  these  many  venules  and  conducts  it 
through  the  apical  foramen. 

Especial  interest  attaches  to  the  thinness  of  the  walls  of  the  pulpal 
vessels.  The  arteries  are  almost  entirely  without  the  external  fibrous 
coat  and  the  muscular  layer  is  represented  by  a  single  involuntary 
fiber,  while  the  veins  have  only  a  single  layer  of  endothelial  cells  to 
form  their  walls.  For  this  reason  the  pulp  is  particularly  unable  to 
resist  any  tendency  to  hyperemia,  and  as  the  tissue  is  confined  in  a 
cavity  with  unyielding  walls,  the  pulp-cavity,  and  as  the  apical  exit 
from  it  is  small  and  easily  blocked,  hyperemia  of  the  pulp  is  attended 
with  a  greater  amount  of  pain  than  in  any  part  of  the  body,  because 
the  nerves  are  easily  stimulated  by  the  pressure  of  the  blood  in  the  pulp- 
cavity.  When  inflammation  supervenes  and  inflammatory  products 
are  to  be  removed,  the  absence  of  lymphatics  further  adds  to  the  diffi- 
culties of  the  situation.  These  facts  explain  the  observed  clinical 
experience  associated  with  pathological  conditions  of  the  pulp. 

The  nerves  of  the  pulp  are  transmitted  through  the  apical  foramina 
together  with  the  blood  vessels.  Several  bundles  of  medullated  nerve 
fibers  enter  the  foramen  and  break  up  into  a  plexus  of  nerves  which  are 
widely  distributed  through  the  pulp  tissue.  Just  below  the  layer  of 
Weil,  the  fibers  may  be  seen  to  lose  their  medullary  sheath,  when  they 
penetrate  this  and  are  lost  between  the  odontoblasts.  None  have  been 
traced  into  the  dentinal  tubules.  The  sensory  nerves  of  the  pulp  are 
only  capable  of  transmitting  sensations  of  pain,  which  may  arise  from 
mechanical,  thermal,  or  chemical  stimuli.  It  is  not  possible  to  localize 
these  sensations  to  any  particular  tooth,  so  that  one  is  not  able  to  refer 
them  to  the  tooth  in  which  they  arise.  Pain  originating  in  one  tooth 
may  be  referred  to  any  other  in  either  the  upper  or  lower  series. 

It  has  been  said  that  the  pulp  had  for  its  function  the  nutrition  and 
innervation  of  the  dentin.  While  dentin  is  of  course  a  non-vascular 
tissue,  the  physical  difi"erences  in  new  dentin  and  that  which  is  found 
in  an  old  tooth  are  often  so  great  as  to  warrant  the  belief  that  in  some 
way  it  may  be  changed  after  it  has  formed.  This  of  course  can  only 
be  through  the  medium  of  the  protoplasmic  contents  of  the  tubuli, 
but  how  this  occurs  if  at  all  is  still  only  a  matter  of  conjecture. 

This  is  also  true  of  the  sensory  innervation  of  the  dentin.  The 
dentin  is  sensitive  to  stimuli  of  a  chemical,  mechanical  or  electrical 
nature,  and  the  dentinal  fibrils  are  instrumental  in  delivering  these. 
No  nerve  fibers  have  been  traced  into  the  tubules,  but  nerve  endings 
are  closely  associated  with  the  odontoblasts.     It  is  believed  that  the 


8o  THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 

dentinal  processes  of  these  cells  in  some  way  transmit  the  stimuli. 
Of  course  with  the  removal  or  death  of  the  pulp,  all  sensitivity  of  the 
dentin  ceases. 

THE  PERICEMENTUM. 

The  fibrous  membrane  intervening  between  the  root  of  the  tooth 
and  the  alveolus  is  known  as  the  pericementum  or  peridental  mem- 
brane. While  not  a  tissue  of  the  tooth  proper,  it  serves  to  connect  it 
with  the  osseous  skeleton  and  performs  so  many  functions  associated 
with  the  tooth  that  it  deserves  especial  attention. 

It  is  composed  chiefly  of  white  fibrous  connective  tissue,  and  be- 
sides containing  the  blood  vessels  and  nerves  necessary  for  its  proper 
functioning,  contains  a  variety  of  other  cellular  elements,  the  functions 
of  which  will  be  discussed  later.  The  chief  oflEice  performed  by  the 
pericementum  is  the  retention  and  support  of  the  tooth  in  its  socket,  in 
addition  to  which  it  has  a  developmental  and  nutritive  relation  to  the 
cementum  and  the  alveolus,  and  serves  as  the  touch-organ  of  the  tooth. 
Inasmuch  as  the  fibrous  elements  of  the  membrane  are  in  predomi- 
nance and  as  they  are  related  to  its  chief  function,  they  will  be 
described  first. 

The  fibrous  tissue  of  the  pericementum  is  of  two  kinds — first,  the 
principal  fibers,  so  called  by  Black  because  they  were  greatest  in  num- 
ber and  most  important  in  function,  which  extend  from  the  cementum 
to  the  alveolar  wall  or  into  the  gum  tissue  and  are  attached  to  each; 
and  second,  the  interfibrous  tissue,  which  is  the  fibrous  tissue  com- 
posed of  spindle-shaped  and  stellate  cells  which  intervenes  between 
the  principal  fibers  themselves  and  between  these  and  the  other  perice- 
mental elements.  These  fibers  pass  from  the  tooth  to  the  alveolar 
wall  in  all  portions  of  the  socket,  their  ends  are  firmly  built  into  the 
cementum  at  one  end,  in  which  they  are  spoken  of  as  Sharpey's  fibers, 
and  into  the  bone  of  the  alveolar  process  at  the  other,  and  they  me- 
chanically support  the  tooth  in  its  socket.  Their  arrangement  is 
somewhat  different  in  different  parts  of  the  membrane  and  so  it  will 
be  necessary  to  give  their  direction  in  its  various  portions.  In  the 
gingival  portion  of  the  membrane,  where  they  are  thickest,  they  extend 
from  the  cementum  in  three  directions.  (Fig.  104.)  One  set  passes 
occlusally  into  the  gingivus  to  support  this  and  make  it  hug  the  neck 
of  the  tooth,  and  another  passes  over  the  alveolar  border  to  blend 
with  the  fibers  of  the  muco-periosteum  of  the  alveolar  process.  These 
two  sets  of  fibers  are  in  greatest  abundance  on  the  lingual  side  of  the 
teeth,  serving  to  protect  this  against  violence  from  food  in  mastication. 


THE    PERICEMENTUM. 


8i 


The  third  set  of  fibers  passes  almost  horizontally  outward  and  they  are 
either  attached  to  the  alveolus,  or  on  the  proximal  sides  in  young  sub- 
jects they  pass  over  to  the  adjoining  tooth  and  become  continuous 
with  its  pericemental  fibers.  Of  this  third  set  of  fibers,  some  pass 
radially  directly  to  the  alveolar  bone,  and  on  the  lingual  side  these 
are  most  numerous,  while  others  after  leaving  the  cemental  surface 
pass  tangentially  in  bundles,  and  are  attached  to  the  process  at  points 
mesial  or  distal  to  where  a  radial  direction  would  have  taken  them. 


Fibers 


Fig.  104. — Section  showing  pericemental  fibers  attached  to  the  cementum.     (Broomell.") 


These  fibers  serve  to  prevent  the  rotation  of  the  tooth  about  its  long 
axis,  while  the  radial  fibers  resist  force  tending  to  move  it  laterally. 
In  the  membrane  intervening  between  the  gingivus  and  the  apex 
of  the  root,  the  principal  fibers  pursue  either  a  straight  horizontal  course 
from  cementum  to  bone  or  they  are  directed  occlusally.  The  effect  of 
this  arrangement  is  to  swing  the  tooth  in  its  socket,  as  it  were,  and  it 
enables  the  tooth  to  resist  the  force  of  mastication  or  any  other  which 
tends  to  depress  it  in  its  socket.     (Fig.  105.) 

6 


82  THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 

In  the  apical  region  the  principal  fibers  extend  radially  from  the  root, 
spreading  out  from  it  in  all  directions  to  the  alveolar  socket. 

The  interfibrous  tissue  fills  in  the  spaces  between  the  principal 
fibers  which  is  not  occupied  by  the  blood  vessels  and  nerves  and  the 
special  cellular  elements  presently  to  be  described. 

This  arrangement  of  the  fibers  of  the  pericementum  is  remarkably 
adapted  to  hold  the  tooth  in  its  socket,  to  enable  it  to  resist  stress  placed 


Fig.  105. — Section  through  alveolus  and  root  of  lateral  incisor  near  the  gingivus 
showing  direction  of  fibers  of  pericementum.  A.  Pulp  with  blood  vessels  and  nerves. 
B.  Dentin.  C.  Cementum.  D.  Alveolar  process.  E.  Interfibrous  portion  of  perice- 
mentum.    (Noyes.     Angle's  Orthodontia.) 

upon  it,  and  yet  to  yield  slightly  to  the  stress  and  thus  to  break  the  force 
of  the  latter.  While  the  fibrous  tissue  is  of  the  inelastic  variety,  the 
fibers  are  not  on  tension  all  the  time,  and  thus  permit  a  certain  elasticity 
to  the  tooth.  This  elasticity  is  contributed  to  in  the  young  membrane 
by  the  blood  vessels,  which  are  very  numerous,  a  condition  which 
has  a  cushioning  effect  upon  the  tooth.  This  elasticity  permits  the 
slight  movement  of  teeth  when  separating  them  for  operative  pro- 
cedures and  in  the  beginning  of  their  orthodontic  treatment. 


THE    PERICEMENTUM.  83 

The  cellular  elements  are  fibroblasts,  cementoblasts,  osteoblasts^ 
osteoclasts,  and  certain  epithelial  structures. 

The  fibroblasts  are  long,  spindle-shaped  cells  found  in  greater  num- 
bers in  the  young  membrane  and  almost  absent  in  that  of  old  age,  and 
are  for  the  repair  of  the  fibrous  tissue.  They  may  be  observed  in  the 
bundles  of  principal  fibers. 

The  cementoblasts  which  are  concerned  with  the  formation  of  the 
cementum,  are  flat,  scale-like  cells  found  on  the  surface  of  the  ce- 
mentum  occupying  spaces  between  the  principal  fibers.  They  are 
irregular  in  outline  and  the  bay-like  depressions  in  their  periphery 
are  occupied  by  fibers.  They  have  oval  nuclei  and  are  difficult  to 
find  in  longitudinal  sections. 

The  osteoblasts  are  situated  upon  the  alveolar  wall  which  they  assist 
in  forming.  They  are  spherical  cells  with  round  nuclei  like  osteo- 
blasts elsewhere  found  in  periosteum.  They  build  the  bone  around  the 
fibers  of  the  pericementum,  thus  strongly  attaching  it  to  the  bone,  and 
the  calcified  fibers  are  here  also  known  as  Sharpey's  fibers. 

The  osteoclasts  are  not  constantly  present  in  the  pericementum, 
but  are  found  when  absorption  of  the  calcified  tissues  is  in  progress. 
They  are  often  spoken  of  as  "giant  cells"  because  of  their  size  and  the 
great  number  of  their  nuclei  of  which  as  many  as  twenty-five  are  some- 
times found.  They  are  capable  of  acting  upon  bone,  cementum  or 
dentin.  Although  the  exact  manner  in  which  they  remove  the  calci- 
fied tissue  is  not  known,  it  is  necessary  for  them  to  be  in  contact  with 
it  and  they  are  found  in  the  bay-like  excavations  which  they  have  pro 
duced.     These  excavations  are  known  as  "Howship's  lacunae." 

The  epithelial  structures  of  the  pericementum  were  first  described 
by  Black,  who  referred  to  them  as  the  glands  of  this  tissue.  While 
their  glandular  character  has  not  been  demonstrated,  they  resemble 
the  glandular  tissue  in  that  they  are  chains  of  cells  epithelial  in  all 
their  characteristics  which  are  distributed  throughout  the  membrane. 
Occasionally  they  appear  arranged  as  a  tubule  having  an  impercepti- 
ble lumen,  but  no  connection  with  the  oral  epithelium  has  been  traced. 

They  are  doubtless  remains  of  epithelial  tissue  carried  down  from 
the  oral  epithelial  at  the  time  of  the  formation  of  the  enamel  organ. 
They  are  fairly  uniformly  distributed  through  the  membrane  accord- 
ing to  a  diagrammatic  plan  by  Dr.  Black. 

The  blood  vessels  of  the  pericementum  are  numerous  and  are  de- 
rived from  three  sources.  Two  or  three  branches  are  given  off  by  the 
artery  of  the  pulp  before  it  enters  the  apical  foramen.  These  anas- 
tomose with  branches  of  arteries  from  the  alveolar  process  and  with 


84  THE    HISTOLOGY    OF    THE    HUMAN    TEETH. 

Others  from  the  mucous  membrane  at  the  gingival  margin,  forming  a 
plexus  of  arteries  which  bountifully  supplies  the  membrane.  These 
are  more  numerous  in  the  young  specimen  and  occupy  approximately 
the  center  of  the  tissue,  but  decrease  in  number  and  size  as  life  ad- 
vances and  in  old  age  are  found  in  channels  upon  the  alveolar  wall. 
The  nerves  are  derived  in  a  similar  manner  from  those  entering  the 
pulp,  from  the  bone  itself  and  from  the  mucous  membrane  at  the  gin- 
givus.  They  unite  and  give  the  tissue  an  abundant  nerve  supply.  The 
medullated  fibers  terminate  without  special  nerve  endings.  They 
transmit  sensations  of  pain  and  ordinary  sensation  and  thus  the  peri- 
cementum is  the  touch-organ  of  the  tooth. 


CHAPTER  III. 

HYGIENE  AND  ARRANGEMENT  OF  LIGHT  IN  THE 
OPERATING  ROOM. 

BY  C.  N.  JOHNSON,  M.  A.,  L.  D.  S.,  D.  D.  S. 

The  hygiene  and  control  of  light  in  an  operating  room  is  a  very 
important  matter,  affecting  as  it  does  the  health  and  comfort  of  the 
practitioner.  In  an  office  where  the  dentist  is  confined  chiefly  to 
operating,  as  is  the  case  in  so  many  today,  it  is  essential  that  some 
attention  be  given  to  the  room  where  the  working  hours  are  mainly 
spent.  It  is  undoubtedly  true  that  many  dentists  have  seriously 
impaired  their  health  and  shortened  their  years  of  usefulness  by  con- 
fining themselves  in  an  abnormal  environment,  and  the  subject  is 
worthy  the  careful  study  of  every  operator. 

The  first  essential  in  an  operating  room  is  good  ventilation  and 
sunlight.  The  operator  should  not  stand  in  a  draft  but  he  should  have 
plenty  of  fresh  air  and  not  breathe  the  vitiated  atmosphere  so  fre- 
quently found  in  dental  offices.  The  admission  of  sunlight  is  very 
important  if  it  can  be  arranged  without  taxing  the  operator's  eyes,, 
though  this  is  not  always  possible  with  the  location  of  many  of  our 
offices.  Sunshine  is  a  great  purifier  and  is  worthy  of  more  considera- 
tion in  this  respect  than  it  usually  receives. 

There  is  a  difference  of  opinion  among  practitioners  as  to  which 
is  the  preferable  light  for  operating,  very  many  urging  the  advantage 
of  a  north  light,  but  this  has  the  limitation  of  not  admitting  the  sun. 
It  would  seem  that  the  best  arrangement  was  to  have  a  corner  room 
for  operating  with  two  windows  in  it  one  for  the  operating  chair  and 
the  other  to  admit  sunlight.  A  north-west  room  lets  in  the  sun  only 
in  the  afternoon  and  in  the  summer  is  very  hot,  and  the  same  may  be 
said  of  a  south-west  exposure.  A  north-east  room  is  better,  having 
the  chair  face  the  north  window  with  the  east  window  at  the  operator's 
back.  But  this  room  admits  very  little  sunshine  in  the  winter 
months  when  it  is  most  needed.  What  is  probably  the  best  arrange- 
ment is  to  have  a  south-east  exposure  with  the  chair  facing  the  east. 
The  sun  is  usually  so  high  by  the  time  operating  begins  that  it  does 
not  interfere  with  the  work,  and  in  summer  it  is  so  far  north  that  it 

85 


86  HYGIENE    AND    ARRANGEMENT    OF    LIGHT 

does  not  shine  in  the  south  window  sufficiently  to  cause  undue  heat. 
During  the  winter  months  it  pours  into  this  window,  flooding  the 
operating  room,  coming  in  at  the  operator's  back,  and  therefore  not 
injuring  his  eyes  by  causing  too  bright  a  light  to  shine  in  front  of  him. 

This  is  a  very  important  consideration  which  many  practitioners 
overlook — the  avoidance  of  too  much  light  for  the  operator  to  face. 
There  is  a  constant  tension  on  the  eyes  when  the  individual  is  looking 
toward  a  light,  and  this  is  equally  true  of  a  reflected  light  which  enters 
from  the  rear  and  is  thrown  back  in  the  face  by  a  bright  wall  in  front. 
This  makes  it  very  essential  that  the  color  of  the  walls  in  an  operating 
room  should  be  such  as  to  absorb  light  and  not  reflect  it.  Bright 
colors  are  to  be  avoided  in  decorating,  and  this  one  room  of  all  others 
should  be  given  over  to  service  rather  than  to  attempt  to  make  it 
attractive  by  the  use  of  light  shades.  Fortunately  it  may  be  made 
comfortable  to  the  eyes  without  sacrificing  artistic  beauty  if  the  proper 
colors  are  selected.  Where  paper  is  used  on  the  walls  it  should  be  a 
solid  color  without  pattern.  Green  is  a  suitable  shade  as  also  is  the 
deep  brown  known  as  chocolate.  The  latter  produces  a  soft,  restful 
effect  in  a  room,  unobtrusive  in  any  way,  and  unobjectionable  from 
an  artistic  sense. 

The  size  and  location  of  the  window  in  front  of  the  operating  chair 
are  important  factors  in  securing  effective  light  without  eye  strain. 
The  window  should  be  sufficiently  high  to  carry  the  light  directly 
down  from  the  sky  into  the  patient's  mouth  when  the  head  is  tipped 
slightly  back,  and  there  should  be  nothing  to  interfere  with  the  direct 
passage  of  the  rays  such  as  trees  in  front  of  the  window  or  tall  buildings 
standing  too  near.  A  very  common  error  made  by  practitioners  is 
the  admission  of  too  much  light  in  the  operating  room.  The  idea 
seems  to  prevail  that  the  more  light  the  better,  but  this  is  a  serious 
mistake.  It  is  true  that  a  very  excellent  quality  of  light  is  required, 
and  in  the  immediate  vicinity  of  the  patient's  mouth  the  light  cannot 
be  too  strong  short  of  sunshine.  But  this  is  the  only  vicinity  where 
it  is  needed,  and  the  diffusion  of  light  over  a  wide  area  by  having  a 
very  large  window  in  front  of  the  chair  is  a  severe  tax  on  the  eyes  which 
few  operators  realize.  If  a  window  is  too  large  some  of  the  light 
should  be  shut  off  with  a  shade,  and  this  is  particularly  true  where 
the  window  runs  down  so  near  the  floor  as  to  flood  the  lower  part  of 
the  room  with  light.  The  operator  is  looking  downward  much  of  the 
time  and  this  flood  of  light  is  reflected  in  his  eyes.  In  any  arrange- 
ment of  an  office  whereby  an  operator  must  use  one  window  for  oper- 
ating and  face  another  as  he  stands  at  his  chair  he  should  cut  off  every 


IN    THE    OPERATING    ROOM.  87 

ray  of  light  from  the  window  he  faces  by  a  dark  shade,  and  in  the  same 
connection  he  should  avoid  anything  on  the  wall  in  front  of  him  which 
will  reflect  the  light  in  his  face.  A  bay  window  while  very  alluring 
to  some  practitioners  is  extremely  bad  unless  the  window  looking 
toward  the  operator's  face  is  heavily  shaded.  The  only  direction 
from  which  it  is  permissible  to  admit  light  to  the  room  except  that 
which  comes  straight  to  the  patient's  face  is  at  the  operator's  back, 
and  as  has  just  been  intimated  there  should  be  nothing  in  front  of 
him  which  would  reflect  this  light  back  in  his  eyes. 

Many  operators  go  on  year  after  year  suffering  eye  strain  and 
unconscious  of  the  cause  of  their  discomfort  through  ignorance  of  the 
essentials  necessary  in  the  arrangement  and  control  of  light  in  the 
operating  room,  or  through  carelessness  in  carrying  them  out.  When 
it  is  considered  how  important  the  eyesight  of  the  dentist  is  it  would 
seem  only  a  reasonable  supposition  that  every  operator  should  give 
some  attention  to  a  matter  so  vital  to  his  future  comfort  and  usefulness 
The  essentials  are  simple  and  are  capable  of  being  carried  out  in  a 
reasonable  degree  at  least  by  every  practitioner. 


CHAPTER  IV.   . 
ASEPSIS  IN  THE  OPERATING  ROOM. 

BY  A.  E.  WEBSTER,  M.D.,  L.D.S.,  D.  D.  S. 

Under  this  heading  must  be  considered  the  possibilities  of  patients 
carrying  contagious  diseases  to  the  dental  office,  and  other  patients 
becoming  infected  from  the  germs  of  disease  left  in  the  plush  dental 
chair,  the  carpets,  curtains,  and  hangings  about  an  operating  room. 
There  is  also  the  more  frequent  and  possible  means  of  transmitting 
disease  to  be  considered,  the  actual  contact  from  instrumentation. 

It  may  not  often  occur  in  an  ordinary  practice  that  patients  suffer- 
ing from  a  contagious  disease  apply  for  dental  treatment,  but  it  does 
often  happen  that  patients  apply  while  members  of  their  family  are 
suffering  from  a  contagious  disease.  Such  diseases  as  measles, 
diphtheria,  whooping  cough,  scarlet  fever,  chicken  pox  and  small  pox 
are  said  to  be  capable  of  transmission  by  clothing.  Then  there  are 
such  diseases  as  tuberculosis,  pneumonia,  influenza  and  some  pus 
infections  which  may  be  transmitted  by  an  unkept  office  equipment. 
Disease  may  be  transmitted  through  the  water  supply,  the  air  supply 
or  noxious  gases.  Even  darkness  is  conducive  to  the  growth  of  micro- 
organisms. 

To  minimize  as  far  as  possible  the  transmission  of  contagious 
diseases  in  a  dental  office  the  operating  room  should  have  an  abundance 
of  direct  sunlight,  there  should  be  no  draperies  or  hangings  about 
the  room.  The  walls  should  be  of  hard  finish  and  capable  of  being 
cleaned.  The  woodwork  of  plain  finish,  no  crevices  for  the  collection 
of  dust.  Cabinets,  brackets  and  shelves  should  be  plain  and  of  hard 
finish.  Drawers  should  not  be  lined  with  baize  or  fabric  of  any  kind. 
The  chair,  and  especially  the  head  rest,  should  be  covered  with  some 
material  which  is  capable  of  being  cleaned  without  destroying  it. 
Plush  is  decidedly  objectionable.  The  floors  should  be  capable  of 
being  cleaned,  as  is  the  case  with  hard  wood  finish  or  linoleum  put 
down  in  a  whole  piece  and  cemented  at  the  edges  so  that  water  may 
not  get  under  it.  If  a  rug  or  cork  is  used  to  stand  upon  at  the  chair 
it  can  be  cleaned  frequently.  Carpet  in  an  operating  room  is  the 
most  unhygienic  of  all  floor  dressings. 

89 


90 


ASEPSIS    IN    THE    OPERATING    ROOM. 


Typhoid  fever  and  other  intestinal  infections  are  most  frequently 
transmitted  by  the  water  supply.  In  some  cities  and  towns  the  water 
is  never  fit  to  drink  while  in  others  it  may  be  drunk  if  boiled  and  in 
others  the  water  may  be  unfit  for  use  only  at  certain  periods.  Water 
which  is  unfit  to  drink  is  unfit  to  wash  a  drinking  glass  or  to  rinse 
the  mouth. 

The  air  supplied  to  an  operating  room  is  of  some  importance, 
especially  to  the  operator,  because  he  so  constantly  breathes  it.  Hot 
air  heating  often  supplies  air  which  is  obtained  from  a  dirty,  damp 
basement  or  from  sewer  ventilators.  Sewer  gas  often  enters  an  oper- 
ating room  from  poorly  trapped  or  ventilated  plumbing.  The  fountain 
cuspidor  is  rarely  trapped  and  is  often  the  source  of  sewer  gas.  Coal 
gas  leaking  from  defective  pipes  is  an  insidious  kind  of  poisoning  that 
an  operator  may  not  notice  for  months.  The  proper  ventilation  of  an 
operating  room  deserves  some  consideration. 

The  keeping  of  an  operating  room  aseptic  is  no  small  under- 
taking. In  fact  it  is  well  nigh  impossible  and  yet  it  may  be  kept  clean 
enough  so  as  not  to  be  the  means  of  spreading  contagious  diseases. 
Dust  is  the  enemy  of  cleanliness  and  health.  Every  crevice,  every 
crack,  every  shelf  and  every  loose  fabric  is  an  element  of  danger.  The 
walls,  shelves,  brackets,  cabinet,  chair,  woodwork,  light  fixtures, 
windows,  in  fact  everything  should  be  thoroughly  cleaned  once  a  week, 
with  a  brush,  soap  and  water.  After  this  the  room  may  be  closed  up 
and  formaldehyde  gas  set  free  in  sufficient  quantity  to  fill  it  and  allowed 
to  remain  for  some  hours.  Formaldehyde  tablets  may  be  evaporated 
by  heat  over  a  Bunsen  burner.  Three  or  four  tablets  may  be  placed 
on  a  piece  of  flat  metal  over  the  gas  flame.  The  heat  necessary  to 
evaporate  the  tablets  is  not  very  great.  An  equally  efficient  method 
is  to  place  a  couple  of  ounces  of  formalin  in  a  dish  over  the  Bunsen 
flame  which  will  quickly  drive  off  the  formaldehyde  gas.  Once 
the  gas  begins  to  come  off  no  one  should  remain  in  the  room  because 
the  gas  is  very  irritating  to  the  air  passages.  The  floors,  chair, 
cabinet,  bracket  and  all  handles  should  be  carefully  cleaned  and 
dusted  with  a  damp  cloth  every  day,  and  if  there  is  any  reason  for 
suspecting  that  a  patient  has  been  in  the  office  who  was  suffering 
from  a  contagious  disease  there  should  be  general  disinfection  and 
ventilation. 

Such  parts  of  the  furniture  and  equipment  as  the  operator  is  likely 
to  handle  in  his  ordinary  duties  should  be  wiped  off  with  a  cloth  made 
damp  by  a  five  per  cent  solution  of  phenol  or  bichloride  of  mercury 
one  to  the  thousand.     There  should  be  no  waste  cotton  or  dressings 


ASEPSIS    IN   THE    OPERATING    ROOM.  9I 

permitted  to  fall  upon  the  floor.  There  should  be  a  convenient  re- 
ceptacle for  such  things,  that  can  be  emptied  frequently  and  sterilized. 
There  is  nothing  much  more  unclean  than  the  ordinary  waste  cotton 
holder  where  the  plier  points  are  drawn  over  the  edges  to  remove 
the  cotton,  unless  the  holder  is  sterilized  after  each  operation.  Soiled 
towels,  napkins  and  rubber  dam  should  be  immediately  removed  from 
the  operating  room. 

The  dental  cabinet  should  be  thoroughly  cleaned  and  wiped  out 
with  a  damp  cloth  once  a  week  and  disinfected  by  the  evaporation 
in  it  of  formaldehyde  gas.  Each  tray  and  shelf  containing  operating 
instruments  should  be  cleaned  daily.  Besides  this  the  tray  containing 
operating  instruments  should  be  covered  with  some  material  which 
can  be  easily  removed  and  sterilized  or  destroyed.  No  instruments 
should  be  permitted  in  the  cabinet  until  they  are  first  sterilized.  A 
fairly  thick  paper  is  quite  suitable  to  cover  the  operating  tray  and  may 
be  removed  after  each  patient  and  a  new  one  placed  in  position. 
What  are  known  as  hygienic  trays  which  are  made  of  glass  or  granite 
are  suitable  and  readily  cleaned. 

The  table  on  the  bracket  arm  is  often  made  of  such  materials  and 
of  such  a  form  that  it  cannot  be  kept  clean.  A  simple  plain  table  of 
glass  without  any  elaborate  frame  to  hold  it  is  all  that  is  necessary. 
Once  any  decoration  is  attempted  there  are  crevices  for  dust.  With 
the  swinging  trays  from  the  cabinet  it  is  not  necessary  that  the  table 
should  contain  places  for  the  operating  instruments,  medicine  bottles, 
gold,  amalgam  and  cement.  The  demand  for  a  dental  equipment 
which  can  be  kept  aseptic  has  given  the  profession  cabinets,  tables 
and  chairs  of  white  enameled  iron.  This  kind  of  equipment  is  easily 
kept  clean  because  of  the  hard  finish  and  the  few  crevices  for  dust. 
The  bracket  table  may  be  covered  with  a  thick  paper  which  can 
be  removed  after  each  operation  and  destroyed. 

The  operator  should  be  suitably  dressed  for  the  work  he  has  to 
perform.  His  coat  should  be  of  washable  material,  close  fitting 
around  the  neck  and  sleeves,  no  buttons  or  flaps  to  catch  in  his  patient's 
hair  or  clothing. 

Long  hair  and  whiskers  are  not  conducive  to  aseptic  operations. 
The  operator  should  aim  to  prevent  his  expired  air  from  entering  the 
patient's  mouth  or  nostrils. 

The  operator's  handsare  almost  impossible  of  disinfection ;  because 
though  the  surface  may  be  sterile  for  a  while  it  soon  becomes  infected 
from  the  natural  exudations  from  the  deeper  parts  of  the  skin.  These 
exudations  may  be  hindered  for  a  time  from  pouring  out  by  the  applica- 


92  ASEPSIS    IN    THE    OPERATING    ROOM. 

tion  of  astringents  but  the  more  the  hands  are  used  the  more  active 
the  glands  become.  Those  hands  which  are  covered  with  a  smooth, 
unabraded  skin  and  have  regular  well  kept  finger  nails  can  be  made 
more  aseptic  than  the  dry,  scaly  hands  with  rough,  irregular  nails. 
Rough  and  violent  scrubbjng  and  scraping  of  the  hands  is  likely  to 
put  them  in  such  a  condition  that  even  this  will  not  clean  them.  The 
nails  are  difficult  to  keep  in  condition  unless  trimmed  short  and 
kept  smooth  by  files  and  brushes.  Sharp  instruments  should  not  be 
passed  under  the  nails  to  clean  them  because  they  scratch  the  tissue, 
leaving  opportunity  for  lodgment  of  bacteria.  Orange  wood  properly 
trimmed  will  serve  to  clean  under  the  nails  without  wounding.  The 
dentist  should  look  upon  his  hands  as  one  of  his  assets  and  should 
avoid  everything  that  might  in  any  way  disfigure  them  or  roughen  the 
skin.  The  hands  should  be  carefully  washed  in  warm  water  and 
soap,  the  nails  scrubbed  thoroughly  and  cleaned  beneath  and  again 
washed  in  running  boiled  water.  This  will  suffice  for  ordinary  cases, 
but  if  the  hands  have  been  exposed  lo  pus  infections  or  the  saliva  of 
the  patient,  or  an  operation  is  to  be  performed  which  demands  the 
breaking  of  the  mucous  membrane  or  entering  the  circulation  of  the 
patient  greater  care  must  be  exercised  in  cleaning  the  hands.  They 
should  be  washed  as  above  and  then  immersed  in  a  one  in  forty  phenol 
solution  for  three  to  five  minutes  or  a  two  per  cent  solution  of  per- 
manganate of  potash,  or  one  in  a  thousand  bichloride  of  mercury. 
Following  this,  alcohol  may  be  poured  over  them.  But  if  absolute 
certain  asepsis  is  demanded  rubber  gloves  should  be  worn.  The 
general  surgeon  of  today  will  not  depend  upon  the  disinfection  of 
his  hands,  but  wears  gloves.  There  is  no  doubt  that  the  dentist's 
greatest  precaution  should  be  to  prevent  the  transmission  of  infection 
from  one  patient  to  another.  While  the  patient  may  become  infected 
from  his  own  saliva  the  dangers  are  not  so  great  as  from  infection 
from  without.  As  the  dentist  operates  for  a  patient  his  hands  are 
certain  to  become  infected  from  contact  with  the  patient's  lips,  face, 
mouth  or  clothing,  and  should  be  cleaned  and  disinfected  as  parts  of 
the  operation  are  reached  which  demand  aseptic  conditions.  The 
operator  should  avoid  touching  his  clothing,  his  face,  hair,  or  the 
furniture  while  treating  roots  of  teeth  or  doing  operations  which  may 
bring  his  instruments  in  contact  with  abraded  surfaces.  Before 
cotton  is  wound  on  a  broach  for  treating  root  canals  the  fingers  should 
be  immersed  in  a  bichlorid  solution  or  a  formaldehyde  solution. 

The  field  of  operation  should  be  as  carefully  prepared  for  operation 
as  the  hands  or  instruments.     Patients  often   visit  the  dentist  whose 


ASEPSIS    IN    THE    OPERATING    ROOM.  93 

mouths  are  not  even  freed  from  particles  of  food  from  the  last  meal 
or  two.  It  is  well  to  have  such  patients  rinse  their  mouths  as  thoroughly 
as  they  can  with  a  two  per  cent  solution  of  permanganate  of  potash 
before  even  a  thorough  examination  is  undertaken.  A  blast  of  air 
from  a  compressed  air  tank  or  a  spray  of  one  of  the  essential  oils  will 
clear  an  area  for  inspection.  Not  having  these  appliances  a  stream 
of  tepid  water  forced  between  the  teeth  will  clear  out  an  interproximal 
space.  Large  cavities  containing  decomposed  food  and  decalcified 
dentin  should  be  opened  and  washed  out  with  abundance  of  water. 
If  the  cavity  is  to  be  filled  at  once  or  the  pulp  involved  the  teeth  in  its 
vicinity  should  be  dried  and  wiped  with  alcohol.  And  if  the  rubber  be 
in  position  all  of  the  exposed  teeth  should  be  thoroughly  sopped  with 
a  strong  disinfectant.  Root  canals  should  never  be  opened  without 
thoroughly  cleansing  the  cavity  itself  and  the  teeth  about. 

The  sterilization  of  instruments  is  perhaps  more  important  than 
the  sterilization  of  the  hands  or  the  field  of  operation  because  they  more 
frequently  come  into  contact  with  the  secretions  of  the  body.  This 
is  especially  true  of  extracting  forceps,  lancets,  clamps,  separators, 
matrices,  files,  trimmers,  scalers,  broaches,  explorers  and  hypodermic 
needles.  Instruments  should  be  selected  with  a  view  to  their  easy 
sterilization.  Cone  socket  instruments  and  deeply  knurled  or  wooden 
handles  are  not  so  easily  sterilized  as  all  steel  and  fairly  smooth  instru- 
ments. The  dental  hand-piece  is  difficult  to  sterilize  without  danger 
of  rust  or  corrosion. 

A  thin  sheet  metal  covering  is  now  made  for  the  hand  piece  which 
completely  covers  it  and  may  be  removed  and  sterilized  between 
patients. 

There  are  two  general  methods  of  sterilization  in  common  use,  (i) 
by  heat  and,  (2)  by  drugs. 

As  a  rule  heat  is  more  certain  but  even  boiling  for  ten  or  fifteen 
minutes  will  not  destroy  the  spores  of  some  organisms.  Sterilizers 
are  most  satisfactory  which  will  permit  of  the  water  being  drained 
off  allowing  the  instrum.  uts  to  dry  from  their  own  heat. 

Sterilization  by  drugs  is  not  always  satisfactory  because  efficient 
drugs  have  to  be  used  in  such  strength  that  unless  the  instruments  are 
wiped  dry  before  using  there  is  a  possibility  of  injuring  the  patient's 
mucous  membranes.  The  odor  and  the  time  required  for  some  drugs 
to  act  are  serious  objections.  A  3  to  5  per  cent  solution  of  formalde- 
hyde will  sterilize  instruments  in  a  shorter  time  than  any  other  drug 
or  combination  of  drugs  which  are  at  all  suitable  for  the  purpose. 
Formaldehyde  solutions  will  rust  instruments  rapidly  but  if  borax 


94  ASEPSIS    IN    THE    OPERATING    ROOM. 

be  added  rust  does  not  occur.  No  dependence  should  be  put  in 
proprietary  disinfectants  for  either  the  mouth  or  instruments.  Suffi- 
cient tests  of  the  efficiency  of  these  nostrums  have  been  made  to  prove 
their  uselessness. 

All  the  instruments  used  in  an  operation  should  be  removed  from 
the  bracket  table  and  washed  in  water  and  sterilized  and  then  placed 
in  their  respective  places  in  the  cabinet.  Such  instruments  as  burs 
and  serrated  surfaces  should  be  cleaned  with  a  brush  before  being 
sterilized.  The  revolving  brush  wheel  on  the  engine  for  cleaning 
burs  is  objectionable  and  should  go  with  the  cotton  holder  unless 
cleaned  after  each  time  it  is  used.  After  broaches  are  sterilized  they 
should  be  kept  in  a  closed  drawer  which  is  frequently  sterilized  with 
formaldehyde  vapor  or  in  alcohol. 

The  hypodermic  needle  may  be  pressed  into  a  cork  which  tightly 
fits  the  bottom  of  a  glass  barrel  about  an  inch  in  diameter  and  three 
or  four  inches  in  depth.  The  cork  may  be  saturated  with  any  steril- 
izing fluid  which  will  not  rust  the  needle.  Such  a  needle  is  always 
ready  for  use.  If  the  barrel  be  deep  enough  the  whole  syringe  may 
be  kept  within  it  and  covered  with  another  cork.  The  nozzle  of  the 
water  syringe  should  be  kept  in  the  formaldehyde  solution  when  not 
in  use.     The  nozzles  of  the  spray  bottles  should  be  similarly  sterilized. 

The  sterilization  of  materials  used  by  the  dentist  deserves  some 
attention.  Gold,  amalgam,  cement,  and  gutta-percha  for  fillings 
need  little  attention  except  where  they  are  brought  into  contact  with 
vital  tissues.  Gutta-percha  is  frequently  brought  into  such  contact 
but  it  is  sterilized  by  heating  before  being  used.  The  phosphoric 
acid  and  chloride  of  zinc  prevent  the  carrying  of  infection  by  the 
ordinary  cements.  Gutta-percha  points  used  to  fill  root  canals  are 
often  inserted  directly  from  an  unclean  drawer  or  box.  They  should 
be  kept  in  alcohol  in  a  wide  mouth  bottle  well  stopped.  Cotton  used 
for  wipes  should  be  sterilized  by  heat  and  kept  covered  as  much  of 
the  time  as  possible. 

There  are  many  minor  operations  performed  by  the  dentist  which 
are  cared  for  in  rather  a  slipshod  method.  Roots  of  teeth  are  ex- 
tracted about  which  purulent  infections  existed  and  no  attempt  made 
to  wash  out  the  cavity  with  any  regard  for  asepsis.  The  water  used 
and  its  containing  vessel  should  be  boiled,  the  syringe  and  the  packing 
should  be  sterile.  Every  office  should  be  equipped  with  sealed  glass 
jars  containing  strips  of  boracic  and  plain  gauze  of  different  widths 
wound  on  a  spool.  Cotton  wipes  may  be  kept  in  a  similar  jar.  The 
jar  and  its  contents  may  be  sterilized  in  an  oven  or  boiling  water. 


ASEPSIS    IN    THE    OPERATING    ROOM.  95 

The  ordinary  fruit  sealer  is  an  excellent  jar  for  this  purpose.  With 
such  an  equipment  the  dental  surgeon  is  always  prepared  for  the 
management  of  the  many  surgical  operations  he  is  called  upon  to 
perform. 


CHAPTER  V. 
HYGIENE  OF  THE  MOUTH. 

BY  GEORGE  H.  WRIGHT,  D.  M.  D. 
ORAL  HYGIENE  OF  THE  INFANT. 

The  highest  physical  development  of  the  child  is  largely  dependent 
upon  its  environment  and  its  food.  These  two  factors  may  be  in- 
fluenced by  the  parent  and  oral  hygienist. 

In  order  to  have  a  clear  understanding  of  the  conditions  necessary 
for  a  sound  oral  hygiene  we  must  recognize  what  physiological  proc- 
esses are  concerned  in  the  development  of  the  oral  cavity,  the  eruption 
of  the  teeth,  and  the  possible  changes  which  may  follow  any  interference 
with  its  normal  process  and  which  may  result  in  a  distinct  pathological 
manifestation.  Heretofore,  in  dealing  with  the  problem  of  oral  hygiene, 
we  have  considered  simply  the  adult,  now  we  propose  to  take  a  view 
of  the  child  when  we  may  first  observe  the  manifestations  of  the 
process  and  activity  of  the  eruption  of  the  teeth. 

An  important  factor  to  be  recognized  is  the  pulsating  mass  of 
pulp  within  the  tooth,  which  acts  as  a  minute  force  constantly 
applied  that  impels  and  moves  the  tooth  onward  and  out  of  its 
crypt  through  the  gum  tissue.  Any  interference  in  this  process 
induced  by  unnatural  external  means  may  so  modify  the  direction  of 
the  eruption  of  these  teeth  as  to  cause  not  only  reflex  disturbances  of 
digestion,  with  many  other  manifestations  of  pathological  diseases, 
but  may  also  modify  the  superstructure  of  the  superior  maxilla  and 
cause  decided  malformations  in  all  the  facial  bones,  including  the  floor 
of  the  nasal  fossa,  the  nasal  septum,  and  the  antra,  and  may  also  in- 
duce abnormal  growths,  thickenings  of  mucous  membrane,  enlarged 
adenoids  and  other  obstructions  that  disturb  normal  functioning. 

Frequently,  the  physician  called  in  to  attend  a  child  who  is  dis- 
turbed in  the  process  of  teething,  so  called,  will  indiscriminately  lance 
the  gum,  a  fibrous  tissue  immediately  over  the  erupting  crown,  and 
in  that  manner  seek  to  give  the  child  relief.  He  may  succeed  tempora- 
rily, because  the  arterial  tension  below  the  erupting  tooth  is  relieved. 
The  cusps  of  the  tooth  emerge  through  the  wound  and  there  is  liber- 
ated into  the  oral  cavity  a  mass  of  liquefied,  alveolar  bone  and  degen- 
erate connective  tissue  which  normally  is  absorbed  by  the  lymphatics. 

97 

7 


pS  HYGIENE    OF    THE    MOUTH. 

Only  the  crown  of  the  tooth  is  formed  at  this  time  and  is  loosely  held 
within  its  alveolar  crypt.  The  lancing  relieves  the  tension  which 
later  subsides,  and  often  the  tooth  returns  to  its  former  position  below 
the  gum;  the  cicatrix  heals  rapidly  and  histologically  will  exhibit  a 
denser  fibrous  mass,  considerably  matted,  and  very  resistant,  and  very 
difficult  for  the  erupting  tooth  to  cut  through,  in  which  event  the 
lancing  may  give  temporary  relief,  yet  in  reality  be  the  means  of 
causing  a  retarded  normal  eruption.  At  birth,  the  crowns  of  all 
the  temporary  teeth  are  formed,  and  any  change  in  environment  of 
a  tooth  may  have  an  important  influence  upon  the  future  lines  of 
growth  of  the  jaws  and  adjacent  structures,  for,  coincident  with  the 
eruption,  we  have  the  development  of  the  inferior  meatus  of  the  nose; 
at  birth  it  is  relatively  unformed.  The  maxillary  sinuses,  sphenoidal 
and  frontal,  are  post-natal  developments.  At  birth  the  developing 
crowns  of  the  permanent  teeth  occupy  the  position  of  the  maxillary 
sinuses.  The  immediate  result  of  this  retarded  eruption  may  be 
observed  in  a  decided  deflection  of  the  lines  of  growth,  not  only  of  the 
alveolar  periosteum,  but  also  of  the  adjacent  bones.  In  the  region 
of  the  intermaxillary  bones,  where  the  central  incisors  have  been  held 
for  an  abnormal  length  of  time,  the  rest  of  the  structure  immediately 
above  will  suffer  a  corresponding  retarded  elongation.  This  may  be 
observed  in  a  later  bending,  or  buckling,  of  the  nasal  septum,  thereby 
closing  on  one  side  the  nasal  fossa,  and  on  the  other  exhibiting  a  very 
wide  opening  so  that  the  intranasal  space  is  too  wide  on  one  side 
which  admits  a  too  great  inrush  of  air,  and  on  the  other  a  congestion 
that  admits  of  none  with  its  attendant  complications. 

These  deformities  have  their  origin  during  the  period  of  and  par- 
ticularly after  the  eruption  of  the  first  teeth;  later  the  arch  of  the  teeth, 
or  substructure  of  the  superior  maxilla,  loses  some  of  its  units  of  strength 
in  supporting  this  structure,  because  the  points  of  contact  of  the  tem- 
porary teeth  are  unequal.  Undue  pressure  is  brought  to  bear  at  iso- 
lated points  in  closing  the  mouth,  with  the  reflex  result  that  there  will 
be  distortion  in  the  structure  above.  The  permanent  teeth  which  are 
developing  immediately  following  the  temporary  teeth,  continue  this 
tendency  to  deformity,  and  the  process  may  go  on  up  to  twelve  years  of 
age  and  then  may  become  progressively  worse.  In  the  meantime  some 
enthusiast  for  early  extraction  may  further  complicate  this  deformity 
by  the  removal  of  some  of  these  teeth  mal-placed,  and  at  this  point 
we  find  one  of  our  greatest  complications  as  it  leads  to  an  abnormal, 
unhygienic  condition  of  the  mouth.  Triangular  spaces  are  formed ,  into 
which  are  lodged  accumulations  of  detritus  difficult  to  remove,  and,  in 


ORAL  HYGIENE  OF  THE  INFANT.  99 

consequence,  there  follows  in  its  train  most  of  the  destruction  of  the 
teeth  through  caries,  impaired  digestion  and  imperfect  respiration. 

We  know  that  the  crown  of  enamel  with  its  interlining  of  dentin 
is  formed  first,  and  subsequently  the  dentin  thickens  and  elongates; 
then  it  becomes  covered  with  cementum,  and  ultimately  the  root  or 
fang  is  developed  with  its  covering  of  peridental  membrane.  But 
this  completed  growth  is  not  a  necessity  for  the  eruption  of  the  tooth, 
because  we  find  upon  dissection  of  the  jaws,  from  six  months  up  to  six 
years,  that  the  teeth  erupt  frequently  without  a  vestige  of  a  root,  and, 
consequently,  the  disturbances  within  the  oral  cavity,  and  reflected  in 
impaired  digestion  of  the  child — to  be  described  in  detail  later — 
are  not  "due  to  the  elongation  of  the  root  and  consequent  pressure  upon 
the  developing  jaw,"  but  to  some  other  cause. 

This  is  fundamentally  a  problem  for  the  specialist  in  oral  hygiene, 
inasmuch  as  the  mother  of  the  child  will  frequently  inquire  of  her  den- 
tist, how  soon  she  must  "begin  the  care  of  baby's  mouth."  Fre- 
quently a  child  from  four  to  six  years  will,  either  through  an  accident 
lose  the  central  temporary  incisors,  or  loosen  them  by  the  habit  of 
prying  a  pencil  between  the  teeth;  soon  they  are  removed  by  the  child, 
parent  or  dentist.  At  this  period  in  the  development  of  the  per- 
manent central  incisors  (immediately  following  the  temporary  incisors) 
we  find  only  the  broad  crown  of  enamel  and  no  roots,  and  the  crown 
situated  high  in  the  intermaxillary  proce^.  The  too  early  loss  of 
these  temporary  teeth,  from  whatever  cause,  may  induce  a  thickening 
in  the  floor  of  the  nasal  fossa  and  malformation  of  adjacent  structures, 
because  the  permanent  central  incisors  are  held  by  a  new  deposition 
of  alveolar  bone  and  a  denser  fibrous  mass  of  gum  tissue.  Concurrent 
with  the  continued  deposition  of  dentine  and  cementum  at  the  apex 
of  the  tooth,  the  erupting  force  is  reduced,  because  the  apical  region 
becomes  more  constricted,  thereby  reducing  what  is  normally  a  wide 
area  of  vascular  pulsating  tissue  which  was  the  impelling  force  nec- 
essary for  the  eruption.  These  malformations  become  important  factors 
in  producing  the  subsequent  pathological  conditions  within  the  mouth. 

The  erupting  tooth  of  a  child  slowly  develops  to  the  surface  after 
absorption  of  the  alveolar  periosteal  crypt  immediately  above,  and  ul- 
timately cuts  its  way  through  a  fibrous  mass  of  gum  tissue.  It  is 
hastily  assumed  that  all  possible  disturbance  with  that  particular  tooth 
has  ended,  but  a  few  hours  later,  or  the  next  day,  the  tooth  may  dis- 
appear below  the  gum  into  its  crypt,  leaving  a  small  orifice  capable  of 
lodging  decomposing  food  and  myriads  of  bacteria. 

The  fluctuating  of  the  teeth  in  their  coming  and  going  shortly  after 


lOO  HYGIENE    OF    THE    MOUTH. 

their  first  appearance,  is  undoubtedly  due  to  the  change  in  arterial 
tension  which  is  manifested  through  the  large  vascular  pulp  of  each 
tooth.  It  is  possible  to  record  the  pulsations  of  the  heart,  and  count 
its  beat  through  the  freshly  erupted  tooth.  The  writer  has  made  ob- 
servations during  the  past  few  years  and  watched  this  phenomenon. 

Under  normal  conditions,  the  process  of  eruption  is  a  natural  and 
orderly  physiological  procedure  on  the  part  of  nature.  It  is  not  our 
intention,  nor  within  our  province  at  this  time,  to  go  into  details  con- 
cerning the  periods  at  which  the  groups  of  teeth  erupt;  that  has  been 
dealt  with  in  another  chapter.  We  shall  consider,  however,  those  as- 
pects which  either  directly  or  indirectly  induce  disturbances  within  the 
oral  cavity,  and  which  we  are  called  upon  to  treat  in  order  to  establish 
a  sound  hygiene  in  the  mouth. 

The  mother  invariably  consults  with  her  dentist  upon  the  first 
occasion,  after  giving  birth  to  her  child.  There  have  been  excessive 
changes  of  metabolism,  which  have  occurred  during  the  period  of 
gestation,  and  this  is  reflected  quite  markedly  in  the  secretions,  and 
particularly  in  the  saliva  and  oral  secretions,  which  become  more  acid, 
and  in  consequence  exerts  a  deleterious  influence  on  the  teeth  and  ad- 
joining tissues.  If  the  patient  has  been  carefully  instructed  during  the 
period  of  gestation  as  to  the  proper  hygiene  for  the  mouth,  the  evil 
effects  upon  the  teeth,  as  a  result  of  the  changed  metabolism,  need  not 
be  fraught  with  so  many  evil  results,  as  when  entirely  neglected  and 
the  debris  naturally  formed  within  the  mouth  is  allowed  to  accumulate. 
^  Immediately  preceding  or  at  the  time  of  the  eruption  of  the  teeth, 
there  may  be  pathological  complications  within  adjacent  structures, 
as  in  the  eye,  ear,  nose  and  throat.  With  this  enormous  structural 
upbuilding  where  nature  is  elaborating  the  materials  for  forty-eight 
teeth,  and  the  jaws,  there  is  much  waste  tissue  to  be  disposed  of.  In 
close  proximity  to  the  erupting  second  lower  molar  there  is  a  thick 
plate  of  alveolar  bone.  This  bone  and  fibrous  gum  tissue  in  contact 
must  be  liquefied  and  absorbed  before  the  tooth  comes  through.  Some- 
times there  will  be  a  swelling  in  the  region  of  the  submaxillary  gland 
and  lymphoid  enlargements;  intense  pain,  excessive  salivation,  fol- 
lowed by  a  hot  and  feverish  condition  of  the  oral  mucous  membrane, 
extending  to  the  nasopharyngeal  region.  The  disturbance  may  con- 
tinue until  we  find  an  acute  otitis  media,  with  a  sinus  and  profuse 
suppurative  discharge  through  the  external  ear,  which  undoubtedly 
had  its  inception  in  the  engorgement  of  tissue  in  the  nasopharynx  or 
enlarged  adenoids  encroaching  upon  the  opening  to  the  Eustachian 
canals  and  thereby  preventing  normal  drainage.     Usually  within  a 


ORAL    HYGIENE    OF    THE    INFANT.  lOI 

few  hours  or  two  days  at  least,  the  offending  molar  will  make  its 
appearance  through  the  gum,  and  disturbance  will  cease.  So,  too,  in 
the  region  of  the  upper  first  and  second  temporary  molars,  we  may 
find  lymphatic  enlargements  involving  the  parotid  and  lachrymal 
gland  and  tonsil,  with  sinus  and  discharge  through  the  lachrymal 
duct.  The  faucial  tonsil  and  normal  adenoid  upon  the  side  nearest 
to  the  erupting  tooth  may  become  considerably  enlarged  through  the 
influence  of  the  lymphatically  absorbed  waste  tissue.  Nature  has 
undoubtedly  developed  and  placed  these  lymphoid  organs  for  a 
useful  purpose  during  this  structural  upbuilding.  Wanton  destruction 
or  removal  without  adequate  cause  is  to  be  deplored. 

If  our  observations  regarding  the  arterial  tension  preceding  and 
after  the  eruption  of  the  tooth  are  correct,  it  is  safe  to  assume  that  blood 
pressure  has  been  a  potent  factor  in  the  primary  process  of  eruption, 
long  before  it  has  reached  the  surface  through  absorption  of  the  walls 
of  its  bony  crypt.  If,  during  this  early  process  before  the  appearance 
of  the  tooth,  or  the  congestion  of  the  fibrous  gum,  there  should  be  from 
any  cause  whatever  an  undue  arterial  tension,  then  some  of  the  dis- 
turbances noted  in  the  young  child  may  be  accounted  for,  although 
there  may  be  no  external  evidence  of  the  teeth. 

There  may  be  a  feverish  restlessness,  periods  of  excessive  salivation, 
desire  of  the  child  to  bite  its  fingers,  and  rub  its  eyes  and  nose.  There 
may  be  bright  red  areas  in  the  region  of  the  parotid  and  sublingual  glands 
externally;  possible  rise  in  temperature,  with  fretfulness  and  nervous 
irritability,  and  reflex  disturbances  of  digestion,  with  frequent  ejec- 
tions of  its  food.  The  mucous  membrane  of  the  mouth,  under  these 
circumstances,  may  exhibit  a  hot  and  dry  surface  that  lasts  for  a  few 
hours  to  be  followed  by  salivation. 

The  etiology  of  these  disturbances  in  the  majority  of  cases  may  be 
referred  to  improper  feeding,  as  imperfect  formulae  for  artificial  foods, 
too  much  food,  uncleanliness,  or  indiscriminate  feeding,  also  where 
artificial  foods  are  swallowed  too  rapidly  and  in  abnormal  quantities. 
Here,  too,  we  may  observe  the  beginning  of  maxillary  deformities, 
because  the  child  does  not  exercise  its  muscles  and  jaws  as  when 
sucking  at  the  breast,  consequently,  through  lack  of  function,  the 
palatal  arch  is  not  adequately  expanded. 

The  child  taking  its  nourishment  at  the  breast  obeys  a  natural 
instinct,  and  the  mother's  milk  during  the  first  months  of  feeding  in- 
creases in  quantity  with  the  larger  demands  of  the  child,  and  analysis 
shows  a  decline  in  the  nutritive  proteids  toward  the  end  of  the  period  of 
lactation.     The  child  thrives  best  at  the  breast  when  the  conditions 


I02  HYGIENE    OF    THE    MOUTH. 

are  normal.  When  otherwise,  then  artificial  feeding  by  formula  is 
resorted  to,  but  instead  of  a  decrease  in  the  quantity  and  proteid  con- 
stituents of  the  food  as  observed  in  nature's  method,  we  find  the  exact 
reverse,  and  the  child  suffers  often  in  consequence  of  haphazard,  arti- 
ficial feeding,  where  the  food  values  are  progressively  increased,  while 
the  naturally  fed  child  is  getting  but  a  simple  diet  and  that  sparingly. 
It  is  not  a  question  as  to  how  much  food  the  child  shall  take,  but  how 
little  it  should  take,  in  order  to  preserve  the  balance  of  perfect  assimila- 
tion and  growth. 

The  salivary  glands  of  the  child  are  functionally  active  from  four 
to  six  months,  and  it  is  claimed  that  even  in  the  youngest  infant  the 
chemical  constituents  of  the  saliva  are  capable  of  rendering  soluble 
starchy  foods.  Some  children  have  been  known  to  digest  and  assimi- 
late starch  during  the  earliest  months,  yet,  upon  general  principles,  it  is 
considered  very  unwise  to  introduce  starchy  foods  of  any  kind,  because 
of  the  mechanical  irritation  and  frequent  inability  to  digest  and  as- 
similate them. 

The  one  great  remedy  for  reflex  disturbances  of  digestion,  as  a 
result  of  undue  tension  within  the  highly  vascular  tooth  pulp,  will 
be  found  in  reduced  and  careful  feeding,  and  the  establishment  of 
normal  hygienic  conditions.  It  may  be  necessary  to  starve  the  child 
for  twenty-four  hours  before  beginning  with  a  simple  and  reduced 
diet,  in  order  to  build  up  again. 

In  describing  the  pathological  aspect  of  the  oral  tissues  in  the  child, 
the  writer  in  the  following  has  drawn  largely  from  the  admirable 
description  found  in  Barrett's  Pathology,  Holt's  Infancy  and  Child- 
hood, and  Forchheimer. 

Stomatitis,  in  relation  to  disturbances  or  inflammation  of  the  mucous 
membrane  of  the  mouth  and  adjacent  tissues,  is  in  this  sense  restricted 
in  its  application,  although  the  term  is  a  broad  one  and  could  be  applied 
to  many  diverse  conditions.  Stomatitis  is  common  in  infants,  and  is 
usually  the  handmaid  of  bad  hygiene  or  unsanitary  surroundings. 

This  inflammation  of  the  mucous  membrane  is  frequently  found 
where  the  child  is  artificially  -fed,  instead  of  nursing  at  the  breast. 
Either  the  proportion  or  formula  for  food  is  wrong,  or  there  is  not 
sufficient  cleanliness  and  care  in  scalding  the  bottles  and  nipples, 
which  will  inhibit  the  growth  of  fermentative  bacteria.  The  quality 
of  the  rubber  in  the  nipple  undergoes  change,  and  under  the  influence  of 
light  and  heat  decomposes  and  becomes  an  active  source  of  irritation 
to  the  tissues,  which  become  poisoned.  And  even  though  these  con- 
ditions do  not  exist  as  to  improper  feeding  or  unclean  bottles,  it  is 


ORAL    HYGIENE    OF    THE    INFANT.  IO3 

possible  to  develop  a  stomatitis  on  account  of  the  accumulation  of 
debris  from  remnants  of  food  lodged  within  the  orifices  of  erupting 
teeth,  broken  down  epithelial  cells,  and  combined  products  of  inflamma- 
tion, which  should  be  daily  removed  irrespective  of  the  age  of  the  child. 
Sometimes  the  most  careful  and  conscientious  nurse  or  mother  will 
neglect  this  duty. 

A  simple  follicular  stomatitis  is  an  inflammation  of  the  mouths  of 
the  mucous  follicles.  Small  areas  of  the  surface  may  be  involved,  and 
possibly  induce  degenerative  changes  as  deep  as  the  mucosa.  The 
membrane  will  be  flecked  over  with  red  points.  As  the  inflammation 
spreads,  more  follicles  become  involved  until  the  red  points  and  patches 
merge,  and  the  entire  surface  becomes  turgid  and  tumid.  As  we  look 
into  the  mouth,  the  tissues  are  hot,  and  dry,  and  red.  There  is  con- 
siderable sensitiveness,  and  the  child  will  shrink  when  examination 
is  attempted.  In  the  early  stages,  there  will  be  excessive  flowing  of 
watery  saliva  due  to  the  congestion  of  the  blood  vessels  surrounding 
the  glands,  some  febrile  disturbance,  irregularity  of  the  bowels,  and 
either  constipation  or  diarrhea  predominating.  Close  examination 
reveals  swelling  of  the  muciparous  follicles  and  possibly  tiny  cysts,  due 
to  the  accumulation  of  secretions  within  them.  (Forchheimer.)  The 
adjacent  lymphatic  glands  become  slightly  enlarged  and  sensitive. 
Fortunately  the  constitutional  symptoms  with  this  form  of  stomatitis 
are  not  severe;  there  may  be  deranged  digestion,  vomiting,  and  a  mild 
attack  of  diarrhea.  The  disease  runs  a  brief  course,  and  disturbances 
are  usually  easily  corrected  by  care  in  feeding  and  cleanliness. 

In  later  stages,  the  degeneration  spreads,  the  mouth  becomes  dry 
and  parched,  the  blood  vessels  are  congested  and  active  nutrition  is 
interrupted;  then  comes  stasis  or  stoppage  of  circulation,  and  sloughing 
of  the  tissue  commences. 

A  child  that  is  fed  with  a  food  that  it  cannot  properly  digest  and  as- 
similate will  be  poorly  nourished,  and  as  a  result,  almost  any  form  of 
disturbance  may  ensue.  The  irritated  condition  of  the  digestive  tract 
may  produce  diarrhea  and  gastric  disturbances,  and  may  result  in 
ulcerative  stomatitis.  We  have  then  an  advanced  stage  of  the  first 
condition.  The  functions  of  the  mucous  follicles  quite  cease,  and 
cracks  and  fissures  open  in  the  unlubricated  tissue.  All  the  preceding 
symptoms  are  aggravated.  The  child  cannot  take  its  food  without 
difficulty,  and  what  is  ingested  affords  little  nourishment  because  of 
the  gastric  disturbances  that  are  always  present. 

Aphthous  stomatitis,  or  herpetic  stomatitis  as  Holt  calls  it,  is  a 
form  that  may  attack  people  of  almost  any  age,  and  is  characterized 


I04  HYGIENE    OF    THE   MOUTH. 

by  some  special  appearances.  Small  round  or  oval  ulcers  appear 
upon  the  reddened  mucous  membrane  of  the  lips,  cheeks,  tongue,  or 
gums.  They  are  from  one  to  three  lines  in  diameter,  very  little  de- 
pressed, v^ith  a  yellowish  or  white  floor,  and  a  red,  narrow,  perhaps 
slightly  indurated,  border.  Sometimes  two  or  more  of  them  become 
confluent,  thus  forming  an  irregular,  large  ulcer.  When  these  heal  they 
leave  no  cicatrix.  The  aphthae  do  not  spread  like  the  spots  in  ulcera- 
tive stomatitis,  and  they  are  distinctly  painful,  while  the  ulcers  are  not. 

Usually  there  is  an  increased  flow  of  saliva  accompanying  them, 
the  mouth  is  hot  and  feverish  and  the  tongue  heavily  coated.  Some- 
times the  saliva  excoriates  the  skin  and  the  lips  are  thus  kept  con- 
stantly sore.  The  older  ulcers  may  have  the  appearance  of  a  diph- 
theritic membrane,  being  a  dirty  grayish  color. 

It  is  usually  a  self-limited  disease  and  may  cover  a  period  from  5 
days  to  2  weeks.  There  is  a  considerable  doubt  as  to  its  etiology,  but 
Holt*  and  Forchheimerf  agree  that  it  is  of  nervous  origin,  and  not 
proved  to  be  contagious.  It  is  frequently  associated  with  disturbances 
of  the  stomach  and  an  attack  may  be  coincident  with  the  eruption  of 
the  teeth. 

Thrush  is  a  form  of  stomatitis  occurring  in  children  and  dependent 
upon  the  growth  of  a  parasitic  fungus.  This  consists  of  long,  jointed 
threads,  the  saccharomyces  albicans,  which  seem  to  belong  to  the  family 
of  the  moulds.  Thrush  is  undoubtedly  contagious.  If  a  little  of  the 
exudate  from  the  mouth  is  treated  with  a  drop  of  liquor  potassae  and 
examined  with  the  low-power  of  the  microscope,  the  structure  will 
reveal  the  fine  threads  (the  mycelium)  and  the  small  oval  spores. 
Slight  catarrhal  stomatitis,  inadequate  salivary  secretions  and  lack 
of  cleanliness  in  the  mouth  will  favor  its  development. 

Wherever  many  young  children  are  congregated,  as  in  asylums, 
nurseries,  and  foundling  homes,  all  are  liable  to  contagion  of  the 
disease.  It  is  most  frequently  developed  in  children  suffering  from 
malnutrition  or  other  wasting  diseases,  or  from  any  deformities  within 
the  oral  cavity,  as  hare  lip  and  cleft  palate.  On  looking  into  the 
mouths  of  young  infants  a  layer  of  thin  white  patches,  almost  a  mem- 
brane, may  be  seen  covering  the  palatal  arch  and  appearing  as  white 
spots  upon  the  tongue,  while  the  mucous  membrane  about  or  at  the 
borders  of  this  coating  seems  to  be  in  a  healthy  condition.  The  white 
flakes  cannot  be  wiped  or  brushed  off;  any  attempt  to  forcibly  remove 
them  will  induce  bleeding. 

♦Infancy  and  Childhood:  Holt,  247. 
fArchives  of  Pediatrics,  ix,  330. 


ORAL    HYGIENE    OF    THE    INFANT.  I05 

The  preceding  remarks  are  more  especially  applicable  to  infantile 
stomatitis.  The  same  or  analogous  conditions  may  be  induced  in 
adults  by  like  causes.  Anemic  and  poorly  nourished  persons  are 
especially  liable  to  inflammations  of  the  oral  tissues.  The  lips  are 
dry  and  parched,  and  superficial  fissures  and  cracks  in  the  mucous 
membrane  appear.  In  a  less  degree  this  will  be  observable  upon  the 
tongue,  the  buccal  surfaces,  and  in  the  vault  of  the  mouth.  This 
may  continue  for  some  time,  until  finally,  with  the  progression  of  a 
general  febrile  state,  a  more  active  stomatitis  is  developed  that  may  re- 
sult in  a  local  breaking  down  or  ulceration. 

Neglect  of  the  teeth  and  mouth  tissues  is  a  fruitful  source  of  sto- 
matitis in  adults.  Food  is  left  to  ferment  and  putrefy,  and  the  products 
of  this  action  will  be  exceedingly  irritative  to  the  soft  tissues,  as  well 
as  destructive  to  the  hard.  There  will  always  be  gingivitis  present  in 
the  mouths  of  those  who  do  not  give  proper  attention  to  the  removal 
of  foreign  substances  from  about  the  teeth,  and  this,  by  continuity 
of  tissues,  may  spread  all  over  the  mouth.  Usually  the  action  of  the 
saliva  upon  the  portions  freely  washed  by  it  is  sufficient  to  keep  them 
clean  and  normal.  But  between  and  about  the  teeth,  where  food 
remains  for  an  indefinite  time,  in  the  absence  of  proper  care  the  gums 
are  always  irritated  and  more  or  less  congested,  and  this  may  spread 
to  adjoining  tissue,  with  the  result  of  an  acute  stomatitis  in  atonic 
conditions. 

In  infantile  affections  the  very  first  measures  to  be  adopted  nec- 
essarily imply  an  inquiry  into  the  food  and  feeding.  If  the  child  is 
artificially  fed,  the  nursing-bottle  should  be  carefully  inspected,  and 
the  food  that  is  given  must  be  scrutinized.  If  there  is  anything  un- 
sanitary about  either,  it  must  be  at  once  corrected.  The  rubber  nipple 
must  be  sterilized,  or,  what  is  better,  discarded  and  substituted  by  a 
new  one  that  has  been  made  thoroughly  aseptic.  If  the  child  is  poorly 
nourished  through  improper  or  insufficient  food,  that  must  be  remedied, 
and  plenty  of  nutritious  matter  that  can  be  readily  digested  and  assimil- 
ated should  be  given.  If  there  are  diarrheas  or  other  wasting  disor- 
ders, which  will  too  often  be  the  case,  they  must  at  once  be  attended  to; 
it  will  be  impossible  to  build  up  a  patient  while  any  process  of  waste 
is  going  on.  All  unhygienic  surroundings  must  be  remedied,  and 
the  patient  should  be  given  plenty  of  light  and  air,  and  proper  exercise. 
In  short,  beneficent  Mother  Nature,  upon  whom  we  must  finally  rely 
for  a  cure,  must  be  afforded  every  opportunity.  Functional  activity 
must  be  promoted,  and  all  obstacles  removed. 

After  securing  perfect  sanitation  the  local  treatment  will  be  mainly 


I06  HYGIENE    OF    THE   MOUTH. 

depurative  and  stimulative.  If  a  cathartic  is  indicated,  two  drams  of 
castor  oil  may  be  administered.  For  the  local  irritation,  a  mouth 
wash  consisting  of  a  solution  of  five  to  ten  grains  of  chlorate  of  potash 
to  an  ounce  of  water  may  be  used  as  a  mouth  wash.  If  the  child  is  too 
young  to  use  this  itself,  a  swab  may  be  made  by  tying  absorbent  cotton 
to  a  stick  of  proper  dimensions,  and  this  may  be  used  to  apply  the 
solution,  employing  a  proper  degree  of  friction.  If  the  mouth  is  sore, 
it  may  be  applied  with  a  soft  sterilized  gauze — never  use  a  soft  tooth 
brush,  it  carries  infection.  The  mouth  may  be  occasionally  washed 
out  with  the  following  preparation  especially  after  eating: 

I^ — Borax,  30  grains. 

Sodium  bicarbonate,  i  dram. 

Distilled  water,  '  4  ounces. 

Or  the  following  may  be  substituted  in  its  place: 

J\ — Boric  acid. 

Potassium  chlorate,  of  each  15  grains. 

Lemon  juice,  I  ounce. 

Glycerol,  6  drams. 

Never  give  syrups  or  honey  to  a  child,  because  of  fermentation. 

If  there  are  deep  erosions  of  the  mucous  membrane,  or  ulcerative 
surfaces,  it  may  be  necessary  to  cauterize  them,  either  with  silver  ni- 
trate, pure  phenol,  or  chromic  acid  crystals.  The  last  named  are  pref- 
erable in  instances  in  which  they  can  be  conveniently  used.  The 
cauterized  places  should  be  subsequently  dressed  with  a  solution  of 
calendula. 

The  treatment  of  follicular,  or  ulcerative,  stomatitis  in  adults  does 
not  materially  differ  from  that  in  infants,  except  that  more  active  meas- 
ures may  be  used.  The  remedies  may  be  proportionately  increased 
in  strength,  and  personal  care  insisted  upon.  The  teeth  should  be 
thoroughly  cleansed,  and  all  broken  or  sharp  edges  removed.  A  soft 
tooth  brush  should  be  employed  after  every  meal,  only  when  a  normal 
condition  has  been  established,  and  with  it  should  be  prescribed  some 
antiseptic  wash.  A  two  per  cent  solution  of  zinc  chloride  may  be 
used  as  a  gargle.  At  night  a  spoonful  of  milk  of  magnesia  should  be 
taken  into  the  mouth  and  rinsed  about  all  the  teeth,  to  be  left  upon 
them  until  the  morning.  Enough  of  good  nourishing  food  should  be 
given,  and  the  patient  should  have  plenty  of  pure  air  and  sunshine. 

In  cases  of  thrush  in  infants  that  are  badly  or  insufficiently  nourished, 
there  is  usually  more  or  less  of  gastric  or  intestinal  irritation  in  con- 
nection with  the  markedly  atonic  condition.  This  will  probably 
require  the  administration  of  such  correctives  as  rhubarb  and  soda, 


DEPOSITS.  107 

or  lime-water.  When  the  aphthae  occur  in  older  persons  they  are  often 
spoken  of  as  "canker  spots,"  or  "canker  sore  mouth."  The  usual 
treatment  is  roughly  to  cauterize  the  spots  and  dress  them  with  a 
solution  of  calendula.  If  an  active  cauterant  is  not  desirable,  as  in 
children,  the  aphthous  patches  may  be  repeatedly  touched  with  the 
following  solution: 

I^ — Sodium  salicylate  i  dram. 

Distilled  water,  6  drams. 

Or  in  place  of  the  preceding  this  may  be  used 

I^ — Borax,  45  grains. 

Sodium  salicylate,  75       " 
Tinct.  myrrh,  i  dram. 

Distilled  water,  ^  ounce. 

The  chlorate  of  potassium  solution  is  strongly  recommended. 

If  the  aphthae  exist  in  considerable  numbers,  they  may  demand  the 
use  of  antiseptic  mouth  washes.  If  they  are  the  consequence  of  a  general 
anemic  condition,  tonics  and  alteratives  are  of  course  indicated.  While 
they  are  peculiarly  uncomfortable,  the  aphthae  have  no  serious  patholog- 
ical signification,  except  as  they  are  indicative  of  an  atonic  condition. 


DEPOSITS. 

Superficial  deposits  upon  the  teeth  composed  largely  of  inorganic 
precipitates  have  their  origin  from  external  sources,  and  most  fre- 
quently are  derived  from  the  fluids  of  the  mouth.  In  addition  there 
are  accumulations  of  organic  detritus,  as  decomposing  food,  animal 
and  vegetable;  fermenting  starches  and  sugars;  advanced  products  of 
decomposition;  waste  and  broken  down  epithelial  cells  from  the  mucous 
membrane,  and  myriads  of  benign  and  malignant  micro-organisms. 
These  combine  to  form  a  pasty  and  cheesy  deposition,  which  is  found 
about  the  cervical  margins  of  the  teeth  and  gums.  This  mass  is  not 
in  the  nature  or  form  of  a  calcareous  tartar,  and  is  easily  removed  by 
the  frequent  and  habitual  use  of  the  tooth  brush  and  waxed  dental 
floss.  It  is  not  always  necessary  to  use  a  tooth  powder  every  day,  for 
once  the  teeth  have  been  properly  cleaned  by  the  careful  dentist,  it  be- 
comes comparatively  easy  for  the  patient  to  keep  the  mouth  free  from 
this  debris.  It  must  be  emphatically  stipulated,  however,  that  these 
products  of  decomposition  should  be  daily  removed  by  the  patient. 


Io8  HYGIENE    OF    THE    MOUTH. 

In  addition,  if  necessary,  the  dentist  should  insist  upon  seeing  his 
patient  at  frequent  intervals  until  there  shall  have  been  established  con- 
ditions that  indicate  a  normal,  healthy  mouth. 

No  amount  of  filling  and  restoring  of  defective  teeth  will  ever 
suffice  to  maintain  a  healthy  mouth  so  much  as  the  unremitting  care 
and  removal  of  these  organic  deposits.  The  elimination  and  pre- 
vention of  caries  is  dependent  upon  the  destruction  of  the  micro- 
organisms of  decay,  and  the  removal  of  their  acid  products  which  are 
so  destructive  to  enamel  and  dentin.  The  action  of  these  organic 
deposits  is  not  always  readily  appreciated.  The  destructive  effects 
of  the  acid  products  are  seen  in  the  interproximal  spaces  and  angles 
formed  by  overlapping  teeth,  or  where  teeth  have  been  extracted,  leav- 
ing the  space  to  be  filled  in  by  the  unsupported  teeth,  which  cause  a 
tipping  forward,  thereby  forming  triangular  pockets  lodging  food  and 
debris.  The  enamel  may  be  quite  thin  at  the  points  of  contact  in  the 
interproximal  space  and  universally  so,  yet  not  show  an  active  break  in 
the  continuity  of  the  surface.  This  accounts  for  the  apparent  rapid 
destruction  of  the  teeth,  when  in  reality  the  destructive  process  has 
been  going  on  for  years,  the  habit  of  leaving  the  teeth  uncleansed 
from  breakfast  time,  through  the  day,  until  retiring  at  night,  is  a  pro- 
lific source  of  enamel  decalcification. 

Green  stains  are  among  the  simpler  deposits  found  upon  the  teeth 
of  young  children  as  well  as  adults,  particularly  in  the  region  of  the 
cervical  margins.  These  stains  are  wholly  superficial  and  vary  in 
color  from  a  dark  green  or  bronze  to  yellow.  They  are  not  indicative 
of  any  special  pathological  disturbance,  only  in  so  far  as  they  denote 
an  undesirable  condition  in  the  oral  secretions.  Their  early  removal 
is  advocated,  because  they  are  claimed  to  be  from  a  disease  producing 
fungus  which,  if  neglected  and  allowed  to  remain,  will  penetrate  the 
enamel,  and  so  erode  the  surface  as  to  form  a  series  of  granular  pits 
which  ultimately  combine  to  form  a  distinct  cavity. 

Erosions  of  the  enamel  surfaces  frequently  have  their  inception 
through  the  agency  of  the  green  stain  deposits,  and  wherever  there 
is  a  congenital  weakness  in  the  enamel,  as  in  faulty  structure  of  the 
enamel  prisms,  having  soft  white  spots  of  calcification  immediately 
adjacent  to  the  interglobular  spaces  of  the  dentin,  then  erosion  and 
decalcification  and  rapid  destruction  of  tooth  substance  quickly 
follow. 

Other  stains  found  upon  teeth  are  those  deposits  caused  by  the 
excessive  use  of  tobacco  and  tea,  and  sometimes  from  the  use  of  medi- 
cines.    Except  from  the  unclean  appearance  produced  by  these  latter 


DEPOSITS.  109 

Stains,  there  appears  to  be  no  immediate  injury  to  the  enamel  surfaces 
in  consequence.  It  is  important,  however,  that  they  should  be  re- 
moved; this  may  be  done  readily  by  touching  the  stained  area  with  a 
small  amount  of  tincture  of  iodine  then  scouring  with  English  precipi- 
tated chafk.  If  the  surface  is  eroded  and  roughened,  it  must  be 
dressed  down  smoothly  with  cuttle  bone,  or  fine  Arkansas  stone  and 
finally  polished  with  chalk. 

The  salivary  calculus,  and  the  calcareous  accumulations  being 
deposited  about  the  neck  and  roots  of  teeth,  cause  recession  of  the  gum 
tissue  and  inflammation  of  the  peridental  membrane;  these  are  among 
the  most  important  of  the  deposits,  because  the  neglected  accumulations 
induce  diseases  of  the  gums  and  adjacent  tissues,  and  although  local 
and  superficial  in  deposition  may  be  the  precursor  of  more  serious 
disturbances. 

The  salivary  calculus  is  a  deposit  from  the  saliva.  The  calcium 
salts  are  held  in  solution  through  the  agency  of  the  carbon  dioxide 
(CO2)  present  in  the  newly  elaborated  saliva.  This  fluid  is  poured 
into  the  oral  cavity  where  it  encounters  acids  derived  from  a  variety 
of  sources,  and  is  subjected  to  the  action  of  the  ferments  from  decom- 
posing foods.  The  quantities  of  saliva  are  more  or  less  variable; 
this  is  also  true  of  the  calcic  salts  contained  in  it.  The  carbon  dioxide 
(CO2)  is  held  in  a  very  unstable  solution,  and  upon  exposure  to  the 
oxygen  of  the  air  and  contact  with  the  acids  in  the  mouth,  derived 
from  various  sources,  the  carbon  dioxide  (CO^)  is  liberated,  the  calcic 
constituents  lose  their  solubility,  form  precipitates  upon  the  teeth, 
and  give  rise  to  what  is  commonly  called  salivary  calculus  or  tartar. 
Combined  with  these  calcium  salts  are  products  of  organic  decompo- 
sition, which  cause  the  tartar  to  become  a  powerful  irritant  to  the  gum 
tissue,  and  induces  inflammation  in  the  contiguous  tissues. 

The  deposition  of  salivary  calculus  is  mainly  in  the  region  of 
the  mouths  of  the  salivary  ducts,  as  Wharton's  duct  and  the  duct  of 
Steno.  The  greater  amount  is  liable  to  accumulate  upon  the  lingual 
surfaces  of  the  lower  incisors,  and  opposite  Steno's  duct,  upon  the 
buccal  surfaces  of  the  upper  molars. 

One  of  the  predisposing  factors  in  the  accumulation  of  large  pre- 
cipitates of  tartar  is  found  in  the  fungoid  growths  and  deposits  upon 
the  teeth,  made  up  largely  of  partially  decomposed  food  and  threads 
of  the  higher  bacteria,  as  the  leptothrix  or  streptothrix  actinomyces. 
The  protoplasm  of  the  filaments  of  these  organisms  breaks  up  into 
bacillus-like  elements,  and  all  combine  to  form  an  agglutinating  mass, 
which  holds  the  precipitates  of  calcium  and  becomes  a  nidus  for  a 


no  HYGIENE    OF    THE    MOUTH. 

concretion.  And  although  the  mouth  has  been  kept  free  from  these 
organic  bodies,  it  is  possible  to  find  a  foundation  for  holding  tartar 
deposits  in  the  saliva  itself,  which  is  a  mixed  fluid  derived  from  the 
secretions  from  the  oral  mucous,  parotid,  sublingual  and  submaxillary 
glands.  These  secretions  are  subject  to  considerable  variation,  both 
in  physical  as  well  as  in  chemical  character.  Ordinarily,  saliva  is  a 
clear,  viscid  fluid,  at  times  thin  and  watery  and  at  other  times  thick 
and  ropy.  According  to  Michaels,  it  contains  all  the  salts  of  the 
blood  which  are  dialyzable  through  the  salivary  glands;  this  offers 
a  fair  index  of  the  metabolic  processes  being  carried  on  in  the  entire 
system.  There  are  times  when  the  viscid  and  tenacious  quality  of  the 
saliva  with  its  mucin  constituents  becomes  dried  upon  the  teeth,  form- 
ing masses  of  sordes  (Marshall) ;  this,  together  with  the  debris  of  epi- 
thelial cells,  mucous  corpuscles  and  salivary  corpuscles  offers  a  favor- 
able nidus  for  tartar  deposits. 

CHEMICAL  COMPOSITION  OF  SALIVA, 

The  chief  constituents  of  a  normal  mixed  saliva  are  ptyalin — 
a  diastatic  ferment — mucin,  and  the  chlorides  of  sodium  and  potas- 
sium. In  variable  quantities  traces  of  albumin,  fat,  potassium 
sulphocyanide,  sulphates  and  phosphates  of  the  alkalies  and  alkaline 
salts,  as  the  calcic  phosphates,  calcic  carbonates  and  oxide  of  iron 
may  be  found;  occasionally  also  traces  may  be  found  in  normal  saliva 
of  urea  and  ammonium  nitrate.  "The  source  of  origin  of  the  saliva 
that  contains  these  chemical  constituents  is  from  the  blood,  or  more 
correctly  from  the  plasma,  which  is  filtered  off  from  the  circulating 
blood  into  the  interstices  of  the  glands,  as  of  all  living  textures." 

In  reaction  the  saliva  when  first  secreted  is  slightly  alkaline.  Dur- 
ing fasting,  although  secreted  alkaline,  it  soon  becomes  neutral.  Tests 
of  saliva  with  litmus  paper  frequently  give  an  acid  reaction,  and  this 
may  be  due  to  the  elaboration  of  acids  from  foods,  ferments  and 
bacteria. 

Tomes  gives  the  daily  average  of  the  amount  of  saliva  excreted 
from  800  to  1500  grams,  approximately  from  three  pints  to  a  little 
less  than  a  quart. 

Lehmann  has  estimated  the  specific  gravity  of  saliva  in  health  as 
ranging  from  1004  to  1006,  and  states  also  that  there  may  be  a  rise  as 
high  as  1009  and  a  fall  as  low  as  1002,  without  the  evidence  of  any 
existing  disease. 


CHEMICAL    COMPOSITION    OF    SALIVA.  Ill 

Frerichs*  gives  the  following  chemical  composition  of  mixed  saliva: 

Water 994.10 

Solids: — 

Ptyalin 1.41 

Fat,  0.07 

Epithelium    and    proteids  (including  serum-albumen, 
globulin,  mucin,  etc.) 2.13 

Salts: — 

Potassium  sulphocyanate 


Sodium  phosphate 
Calcium  phosphate 
Magnesium  phosphate 
Sodium  chloride 
Potassium  chloride 


.2.29 


5-9 


1,000.00 


The  excretion  of  the  parotid  gland  contains  slightly  more  water 
than  the  secretion  from  the  submaxillary  and  sublingual  glands,  and 
in  consequence  is  less  viscid.  It  is  rich  in  ptyalin,  but  contains  no 
mucin;  its  calcic  constituents  are  the  carbonate  and  phosphate,  the 
latter  existing  in  minute  quantities.  According  to  Hoppe-Seyler  the 
inorganic  elements  yield  about  0.34  per  cent.f 

The  secretions  of  the  sublingual  and  submaxillary  glands  are  poor 
in  ptyalin  but  rich  in  mucin;  the  sublingual  contain  the  higher  per 
cent.  Carbonate  and  phosphate  of  calcium  yield  about  equal  propor- 
tions. These  elements  amount  to  about  0.43  per  cent  in  the  sub- 
maxillary secretion,  but  the  precentage  is  not  so  high  in  the  sublingual. 

Mucin  is  derived  largely  from  the  mucous  glands,  and  the  organic 
and  inorganic  constituents  average  about  20  parts  to  1,000. 

Berzelius  estimates  the  composition  of  salivary  calculus  as  follows: 

Phosphates  of  calcium  and  magnesium, 79.0 

Sah'vary  mucus, 12.5 

Ptyalin,  i.o 

Animal  matter  soluble  in  HCl 7.5 

Calcic  deposits  from  whatever  source  should  be  removed,  and 
inflammations  of  the  gums  and  mucous  membrane  of  the  mouth  irre- 
spective of  their  origin  must  be  relieved  and  resolved  into  healthy  tissue. 
It  does  not  necessarily  follow  that  because  we  find  large  deposits  of 
tartar  upon  the  necks  of  the  teeth  that  we  have  the  disease  of  pyorrhea 
alveolaris.  We  have  seen  many  patients  whose  teeth  have  been  neg- 
lected, and  who  were  innocent  of  the  smallest  effort  on  the  part  of  a 

♦Kirkes'  Handbook  of  Physiology,    1893,  p,  295 
t  Marshall  Op.  Dentistry,  523. 


112  HYGIENE    OF    THE    MOUTH. 

dentist  in  all  their  lives  as  to  removal  of  the  deposits,  which  were  ex- 
cessive, and  to  whom  the  use  of  a  tooth  brush  was  unknown,  yet,  upon 
the  careful  removal  of  these  deposits  and  orderly  and  habitual  use  of 
the  brush,  the  mouth  was  quickly  restored  to  a  healthy  condition. 

The  deposits  in  some  instances  have  been  exceedingly  thick, 
and  upon  the  lingual  surfaces  of  the  lower  anterior  teeth  an  aggregation 
of  successive  layers  has  formed,  that  completely  bound  the  teeth  to- 
gether as  in  a  plaster  cast.  The  encroachment,  however,  does  not 
always  extend  very  far  below  the  gum,  nor  necessarily  involve  de- 
struction of  the  peridental  membrane.  An  early  treatment  of  such 
conditions,  to  be  described  later,  results  in  complete  restoration  with- 
out the  accompaniment  of  the  disease  designated  pyorrhea  alveolaris. 

SERUMAL  DEPOSITS. 

It  is  not  the  purpose  of  this  part  of  our  work  to  treat  exhaustively 
the  various  authoritative  opinions  as  to  the  etiology  of  the  serumal 
deposits.  We  shall  consider,  however,  a  few  of  them  in  so  far  as  to 
present  a  general  summary  that  will  guide  us  in  recognizing  these 
deposits  which  call  for  special  treatment  in  their  removal.  The  sub- 
ject has  been  considered  more  completely  in  the  chapter  on  pyorrhea 
alveolaris. 

Dr.  John  Marshall,*  in  1891,  said,  "That  the  deposition  of  the 
concretions  upon  the  roots  of  the  teeth  in  those  localities  not  easily 
reached  by  the  saliva,  or  in  which  the  presence  of  the  saliva  would  be 
an  impossibility,  is  due  to  the  causes  which  produce  the  chalky  for- 
mations found  in  the  joints  and  fibrous  tissues  of  gouty  and  rheumatic 
individuals." 

Dr.  G.  V.  Black  has  done  considerable  research  work  and  has 
written  an  exhaustive  paper,  published  in  the  American  System 
of  Dentistry,  Vol.  I,  p.  953,  wherein  he  speaks  of  a  calcic  inflammation 
and  phagedenic  pericementitis  as  an  accompaniment  of  the  tartar  de- 
posits upon  the  teeth  in  the  region  of  the  peridental  membrane,  and 
though  he  indicates  his  belief  that  the  cause  is  wholly  local,  he  also 
admits  that  a  sanguinary  deposit  may  be  closely  involved  in  its  origin. 
He  differentiates  it  as  a  destructive  inflammation  of  the  pericemental 
membrane,  distinct  from  other  inflammations  of  this  tissue  though 
possessing  features  in  common  with  them.  In  summing  up  his  esti- 
mate, he  concludes  that  the  disease  is  essentially  one  of  the  peridental 
membrane  rather  than  of  the  alveolus,  and  the  destruction  of  these 

♦Transactions  American  Med  Assoc,  1891. 


SERUMAL    DEPOSITS.  II3 

two  Structures  is  so  nearly  synchronous  that  it  becomes  difficult  to  say 
which  has  gone  first. 

Dr.  C.  N.  Pierce  *  gives  the  name  ptyalogenic  calcic  pericementitis 
to  the  conditions  wherein  the  teeth  are  involved  with  calcic  deposits, 
indicating,  as  he  believes,  the  origin  of  these  deposits  and  other  calculi 
as  traceable  to  the  saliva.  We  are  not  concerned  particularly  in  this 
section  of  our  paper  with  the  cause  so  much  as  in  adequately  recog- 
nizing the  conditions  in  the  mouth  that  call  for  treatment,  and  the 
establishment  of  a  sound  oral  hygiene. 

W.  C.  Barrett  t  has  summarized  the  theory  of  E.  C.  Kirk  on  the 
formation  of  serumal  calculus  as  follows: 

"The  capacity  of  the  blood  stream  for  holding  in  solution  the  waste 
products  of  nitrogenous  metabolism,  the  results  of  functional  activity 
in  the  body,  is  determined  by  the  alkalinity  of  the  blood  plasma. 
Any  decrease  in  this  diminishes  its  solvent  power  for  these,  and  causes 
their  precipitation  in  the  tissues  nourished  by  the  blood  stream.  This 
lessened  alkalinity  may  be  general,  affecting  the  whole  sanguinary 
current,  or  it  may  be  localized  in  certain  tissues;  in  the  latter  case  there 
will  be  a  localized  precipitation  of  the  products  of  which  uric  acid  is  a 
type.  Excessive  work  causes  an  increased  blood  supply  to  a  part, 
and  excessive  oxidation  and  tissue  waste,  which  in  turn  produce 
lessened  alkalinity,  or  a  tendency  toward  acidity.  The  ligamentous 
tissues  are  especially  liable  to  conditions  of  this  nature,  and  the  peri- 
dental membrane,  belonging  to  this  category,  is  especially  subject  to 
"affections  of  the  character  noted.  Excessive  work  being  put  upon  the 
investing  membrane  of  any  tooth,  through  malocclusion  or  by  bad 
habits  in  mastication,  by  injuries  from  v^^dging,  the  application  of 
ligatures,  or  other  causes,  the  resulting  hyperemia  brings  in  its  train 
overnutrition,  localized  diminished  alkalinity,  with  the  consequent 
deposition  of  urates." 

We  have  thus  considered  those  superficial  deposits  found  upon  the 
teeth  having  their  origin  from  organic  debris  and  the  saliva;  it  remains 
to  briefly  differentiate  those  which  form  upon  the  roots  of  the  teeth 
primarily,  and  are  commonly  designated  sanguinary  calculus.  Its 
characteristic  appearance  is  somewhat  different  from  the  salivary 
calculi,  although  these  latter  may,  through  a  considerable  period  of 
successive  depositions,  become  in  time  a  dense,  black,  smooth  supra- 
gingival  deposit,  having  incorporated  through  the  agency  of  pigmentary 
matter,  oxides  from  amalgam  fillings,  and  the  action  of  medicines, 

*Am.  Text  Bk.  Op.  Dentistry,  2d  Ed.,  p.  510. 
fOral  Pathology  and  Practice:  Barrett,  p.  139. 

8 


114  HYGIENE    OF    THE    MOUTH. 

which  may  cause  it  to  assume  the  external  color  and  appearance  of 
the  sanguinary  calculus. 

The  location  of  these  deposits  would  indicate  their  entire  independ- 
ence in  formation  of  the  oral  fluids,  as  they  are  found  precipitated 
upon  the  periphery  of  a  root  that  is  not  denuded  when  formed,  and 
where  there  is  no  destruction  of  the  gingival  border.  It  is  distinctly 
more  irritating  to  the  tissues  than  the  smooth  amorphous  deposits  from 
the  salivary  calculus,  and  this  may  be  due  to  its  position  within  the 
alveolar  socket  where  it  is  preeminently  a  foreign  body.  The  deposi- 
tions are  not  in  uniform  amorphous  masses,  but  appear  as  separate 
minute  nodules,  which  cling  tenaciously  and  are  with  considerable 
difficulty  removed.  Successive  aggregations  unite  to  form  a  mass  that 
is  hard  and  brittle,  whose  color  is  olive  black  or  olive  green.  It  is 
unlike  the  salivary  calculus  which  may  be  readily  detected,  and  is 
therefore  easy  of  diagnosis,  as  it  is  hidden  away  within  the  socket, 
sometimes  beyond  a  point  of  accessibility  for  its  removal. 

The  removal  of  deposits,  whether  of  salivary  or  serumal  origin, 
demands  the  highest  skill  and  care  in  the  use  of  specially  designed 
instruments  for  this  operation.  No  hurried  and  indifferent  service 
rendered  the  patient  will  ever  restore  the  oral  tissues  to  a  normal  con- 
dition; this  result  is  obtained  only  by  deliberate  painstaking  care, 
combined  with  intelligent  work. 

The  selection  of  proper  instruments  must  be  determined  not  by 
any  arbitrary  rule,  but  according  to  the  requirements  of  the  operation 
to  be  performed,  and  the  writer  has  obtained  the  best  results  from  a 
composite  set  selected  from  the  admirable  instruments  designed  by 
Doctors  Kirk,  Darby-Perry,  King,  Marshall,  Abbott,  Harlan,  Smith, 
S.  S.  White  Manufacturing  Company,  and  J.  W.  Ivory. 

The  instruments  should  be  clean  and  sterilized,  and  everything 
about  them  suggestive  of  care.  The  patient  should  be  comfortably 
seated,  and  the  chair  inclined  and  head-rest  adjusted  in  order  to  have 
the  mouth  receive  the  largest  amount  of  light  possible.  All  napkins, 
large  or  small,  must  be  fresh  and  clean.  The  larger  napkin  should 
be  sufficient  to  protect  the  patient's  clothing  from  flying  particles  and 
loose  debris.  Ordinarily  the  operator  stands  firmly  on  the  right  side 
of  the  patient  with  his  left  arm  around  the  head-rest,  and  by  this 
means  is  in  a  position  to  gently  steady  the  head.  Small  rectangular 
pieces  of  sterilized  gauze  from  4x4  inches  to  5  x  5  inches  are  most  use- 
ful in  receiving  the  soft  deposits  as  they  are  spooned  off.  A  small  piece 
of  gauze  should  be  rolled  and  placed  between  the  lower  lip  and  gums 
to  prevent  pressing  the  septic  matter  into  the  delicate  membrane  of 


SERUMAL    DEPOSITS  II5 

the  lips.  The  lips  may  become  infected  and  considerable  swelling 
be  induced  by  lack  of  care  on  the  part  of  the  operator.  In  order  to 
lessen  this  liability  it  may  be  necessary  to  prescribe  a  suitable  mouth 
wash  and  special  application  of  the  tooth  brush  for  a  few  days  preced- 
ing the  operation  of  removing  the  debris.  Where  conditions  are  ab- 
normal, this  precautionary  treatment  is  of  value  in  preventing  further 
inflammation. 

The  left  hand  should  hold  the  mouth  mirror,  which  serves  the 
double  function  as  a  tongue  depressor  and  light  reflector.  The  eye 
of  the  operator  should  always  follow  the  scaling  edges  of  the  instrument 
as  near  as  possible,  and  whether  the  movement  is  a  drawing  upward  or 
pushing  downward,  the  scaler  should  be  so  held  and  supported  by  the 
fourth  and  fifth  fingers  resting  upon  the  adjacent  teeth,  that  there 
shall  be  no  danger  of  a  slipping  and  plunging  into  the  tissues  of  the 
gums.  When  a  deposit  has  been  definitely  located  and  dislodged, 
it  should  be  immediately  removed  and  accounted  for.  It  may  be 
necessary  to  frequently  syringe  the  tooth  and  membranes  with  a  warm, 
antiseptic  mouth  wash  in  order  to  facilitate  the  complete  elimination 
of  all  foreign  irritants. 

Whenever  there  are  indicated  deposits  below  the  gingival  margin, 
it  is  well  first  to  remove  carefully  the  superficial  deposits  upon  the  sur- 
faces of  the  teeth  above  the  membranous  tissues,  beginning  at  the 
central  incisors  and  cautiously  working  round  the  arch  to  the  third 
molars,  each  half  of  the  mouth  being  treated  successively  until  all 
the  teeth  have  been  scaled.  The  time  necessary  for  this  operation 
will  depend  somewhat  upon  the  conditions  presented,  and  it  may  be 
necessary  to  resume  the  operation  at  a  future  time.  During  this  pre- 
liminary scaling,  mental  note  should  be  made  of  the  pockets  formed 
between  the  roots  where  debris  and  calcic  deposits  accumulate;  minute 
congestion  of  the  gingiva;  triangular  spaces  and  irregularities  as  a 
result  of  inclined  crowns,  and  any  other  factors  predisposing  and 
favorable  to  the  accumulation  of  deposits,  as  cavities  through  caries, 
furrows  between  the  cervical  enamel  and  cementum;  hypertrophied 
tissues;  eroded  cement  fillings;  rough  and  pitted  gold  fillings  and  sur- 
faces; projecting  amalgam  and  other  fillings;  improperly  fitting  clasps, 
artificial  dentures  and  gold  crowns.  All  supragingival  surfaces  should 
be  most  scrupulously  scaled,  cleaned  and  polished  as  a  preliminary 
operation  to  further  removal  of  the  subgingival  accumulations.  It 
matters  not  who  may  be  responsible  for  the  old  restorations,  it  is  a 
necessity  that  the  roughened  fillings  and  surfaces  be  cleaned  and 
polished. 


Il6  HYGIENE    OF    THE    MOUTH 

Incidentally,  the  patient's  attention  may  be  directed  to  certain 
localities  within  the  mouth  where  there  is  a  special  tendency  for  the 
retention  of  decomposing  foods. 

Subgingival  deposits  invariably  induce  distinct  pathological  con- 
ditions within  adjacent  membranes,  and  each  tooth  carrying  upon  its 
surfaces  and  roots  these  foreign  bodies  should  be  treated  individually, 
until  all  trace  and  evidence  of  their  presence  has  been  removed. 

The  tenacity  with  which  serumal  deposits  cling  may  call  for  the 
use  of  a  softening  agent,  and  a  twenty  per  cent  aqueous  solution  up  to 
fifty  per  cent  of  trichloracetic  acid  may  be  used  with  beneficial  results. 
The  percentage  strength  of  the  acid  necessary  is  to  be  determined  by 
trial.  The  acid  is  carried  into  the  region  of  the  deposit,  either  upon  a 
wedge-shaped  piece  of  orange  wood  stick  or  upon  a  few  fibers  of  cotton 
soaked  in  the  acid.  A  gentle  pumping  motion  will  suffice  to  reach  the 
nodular  deposits.  Lactic  acid  has  been  recommended  for  the  same 
purpose  with  claims  for  its  therapeutic  value. 

We  are  now  using  with  beneficial  results  a  solution  of  bifluorid  of 
ammonium,  a  formula  advocated  first  by  Dr.  Joseph  Head  (see 
Dental  Cosmos,  Jan.,  1909).     He  says: 

"This  medicine  primarily  attacks  the  bond  between  the  tooth  and 
tartar,  making  easy  the  removal  of  large  lumps  by  instrumentation. 
It  also  dissolves  the  microscopic  particles  of  calculus  that  have  been 
undiscovered  by  the  scalers. 

"It  seems  to  be  even  more  active  therapeutically  than  chemically, 
since  a  drop  or  two  placed  in  a  pyorrhea  pocket  will  not  only  loosen 
what  tartar  is  present,  but  will  stimulate  the  soft  tissues  to  a  healthy 
reorganization  and  readherence  to  the  tooth.  Even  where  no  deposit 
of  calculus  is  found  on  the  root  within  the  pyorrhea  pocket,  weekly 
applications  of  this  solution  will  cause  readherence  of  the  gum  and  a 
consequent  tightening  of  a  tooth  that  was  formerly  loose.  This 
phenomena  is  explained  by  the  fact  that  a  chemical  solvent  of  tartar 
will  attack  the  crystals  of  urate  of  calcium  that  may  exist  in  the 
diseased  peridental  membrane. 

>'»  "The  bifluorid  solution  when  injected  into  a  chronic  fistula  will 
cause  rapid,  and  in  many  instances  permanent,  healing  by  dissolving 
the  organic  matter  of  the  dead  bone  and  stimulating  the  living  cells  to 
healthy  action.  This  should,  however,  be  done  with  caution,  only  a 
minim  or  two  being  used  as  a  dose,  since  too  large  a  quantity  will 
cause  excessive  stimulation  and  pain  which  may  last  for  hours  with 
considerable  swelling.  This  is  explainable  by  the  fact  that  fistulas 
sometimes  lead  to  large  internal  bony  cavities  and  if  these  are  filled 


SERUMAL    DEPOSITS,  II7 

full,  an  excessive  dose  is  given  to  the  patient.  This,  however,  if  it 
causes  pain  also  causes  rapid  healing,  and  it  is  the  author's  experience 
never  to  have  known  a  case  where  a  large  dose  did  not  result  in  a 
cure  corresponding  in  quickness  to  the  extent  of  the  pain  occasioned. 
However,  smaller  doses  are  to  be  advocated,  as  these  give  satisfactory 
results  and  can  be  obtained  with  little  if  any  discomfort. 

"As  the  bifluorid  solution  attacks  glass,  a  celluloid  or  rubber 
syringe  with  a  platinum  point  is  advisable  for  its  application.  For 
this  purpose  the  bulb  syringe  with  the  celluloid  barrel  and  platinum 
point,  made  by  Dunn  &  Co.  of  Chicago,  is  excellent.  There  is  a 
plunger  syringe  composed  of  celluloid  that  is  also  excellent.  It  was 
invented  by  Dr.  C.  D.  Beedle  of  Leominster,  Mass. 

"There  are  various  quill  applicators,  but  these  do  not  give  the  best 
results  as  the  medicine  reaches  the  bottom  of  the  pocket  in  a  diluted 
condition,  whereas,  if  the  syringe  point  is  carried  to  the  bottom  of 
the  pocket  and  slightly  withdrawn,  the  entire  pocket  can  be  filled, 
the  undiluted  solvent  being  placed  at  the  deepest  point  where  it  is 
most  needed. 

"It  is  a  curious  fact  that  the  more  times  a  patient  receives  an  ap- 
plication of  the  bifluorid,  the  less  it  irritates  the  gums,  although  the 
therapeutic  effect  is  not  diminished.  Some  patients  can  stand  the 
application  without  pain  or  discomfort  for  four  or  five  minutes,  the 
average  can  bear  it  from  one  to  two  minutes,  a  few  can  stand  it  only 
for  a  few  seconds,  when  the  mouth  should  be  immediately  rinsed  with 
water,  which  is  all  the  neutralization  that  should  be  used  where  the 
therapeutic  effect  of  the  drug  is  to  be  obtained  in  a  continuing  effect. 
Where,  however,  too  much  irritation  is  experienced  through  lack  of 
caution  in  its  application,  the  rinsing  of  the  mouth  with  milk  of 
magnesia  will  rapidly  reduce  the  sensitiveness,  although,  as  before 
stated,  the  therapeutic  value  of  the  application  will  be  rendered 
negative. 

"  Bifluorid  of  ammonium  is  sold  under  the  trade  name  of  Tartsol 
and  is  for  sale  at  the  S.  S.  White  Dental  Mfg.  Co." 

The  chiseling  and  scaling  and  applications  of  the  acid  may  be  re- 
peated until  all  the  nodules  are  removed,  and  the  roots  are  clean  and 
smooth.  Care  must  be  exercised  not  to  lacerate  the  tissue  of  the  gums 
and  peridental  membrane.  The  force  employed  should  be  well  under 
the  control  of  the  operator  to  avoid  destruction  of  the  cementum,  and 
unnecessary  loosening  of  the  tooth.  Too  murVi  movement  of  the  tooth 
within  the  alveolar  socket  is  liable  to  carry  granules  of  calcific  deposits 
and  septic  matter  further  into  the  pocket  and  tissues.     Should  the 


Il8  HYGIENE    OF    THE    MOUTH. 

teeth  be  very  loose,  a  temporary  supporting  splint,  made  of  softened 
modeling  compound,  and  applied  to  the  labial  surfaces  of  the  teeth  en 
masse,  when  the  lingual  surfaces  are  under  treatment,  will  be  an  effective 
and  agreeable  support;  the  reverse  application  when  the  labial  surfaces 
are  treated.  Frequent  syringing  with  a  warm  antiseptic  mouth  wash, 
such  as  phenol  sodique  or  peroxide  of  hydrogen  (H^Oj)  three  per 
cent  solution,  to  remove  debris  is  necessary. 

The  author  counsels  against  a  too  early  application  of  massaging 
of  the  gum  tissues,  because  of  the  danger  of  incorporating  within  the 
tissue  loose  deposits  that  become  a  continual  source  of  irritation.  This 
operation  may  be  deferred  until  later  when  all  trace  of  inflammation 
has  disappeared,  and  careful  exploring  reveals  no  deposits. 

Ultimately,  a  weak  solution  of  zinc  chloride  may  be  worked  into 
the  pockets  as  a  stimulating  astringent.  New  vitality  may  be  induced, 
bringing  new  granulations  to  the  alveolar  edges  by  scraping  with  a 
bur  or  hoe  excavator. 

The  treatment  should  end  when  all  is  clean,  and  there  is  an  eflfusion 
of  coagulable  lymph,  which  should  be  left  and  not  washed  or  wiped  out, 
because  at  this  point  nature  can  accomplish  much  in  the  restorative 
process. 

The  dentist  should  determine  for  his  patient  how  soon  this  op- 
eration should  be  repeated,  and  that  will  be  governed  by  keeping  a 
careful  record  of  the  status  of  the  case  with  treatment  and  results  for 
future  reference. 


CHAPTER  VI. 
DENTAL  CARIES. 

BY  C.  N.  JOHNSON,  M.A.,  L.D.S.,  D.  D.  S. 

In  a  work  like  the  present  it  is  deemed  unnecessary  to  go  minutely 
into  the  pathology  of  this  disease  and  yet  it  is  well  to  consider  some- 
what carefully  certain  of  the  etiological  factors  which  affect  us  vitally 
in  operative  dentistry.  Every  operator  who  attempts  to  save  the 
natural  teeth  should  have  a  reasonably  clear  conception  of  the  cause 
or  causes  of  caries,  of  its  modus  operandi,  and  the  peculiar  methods 
of  its  attacks.  If  he  is  thoroughly  informed  on  these  points  he  will 
be  in  a  position  to  do  better  work  thereby,  and  recognizing  this  the 
foremost  men  in  the  profession  have  always  sought  to  inform  them- 
selves in  regard  to  these  matters. 

Some  of  the  theories  of  the  past  have  been  so  wide  of  the  mark 
that  they  are  interesting  only  as  milestones  along  the  uphill  road  of 
scientific  progress,  while  others,  though  crude  and  lacking  in  demon- 
strated data,  are  worthy  of  the  greatest  respect  in  the  light  of  the  most 
recent  knowledge.  Certain  writers  have  held  the  theory  that  inflam- 
mation played  a  part  in  the  breaking  down  of  the  tooth  tissue,  that  the 
character  of  the  tooth  structure  itself  was  the  most  significant  thing 
connected  with  it,  and  that  the  disease  progressed  from  within  outward. 
Others  thought  that  while  the  disease  began  upon  the  surface  of  the 
tooth  and  progressed  inwardly  it  was  due  chiefly  to  the  chemical 
reaction  of  the  saliva,  that  in  fact  it  was  acid  saliva  which  produced 
the  decay.  But  it  was  inconceivable  to  think  that  the  saliva  ever 
became  sufficiendy  acid  to  eat  into  a  tooth  in  the  manner  in  which  we 
find  caries  progressing,  or  that  the  soft  tissues  could  tolerate  it  if  it 
did.  Not  only  this  but  if  the  saliva  did  the  work  we  would  find  the 
teeth  attacked  uniformly  upon  all  surfaces  bathed  in  saliva  while 
as  a  clinical  fact  there  are  certain  surfaces  in  which  decay  seldom 
or  never  has  its  initial  point  of  entrance.  Some  of  our  close  observers 
noted  these  thirgs  and  away  back  as  far  as  1828  Robertson  indicated 
that  the  carious  process  was  due  to  the  action  of  some  agency  occurring 
immediately  at  certain  points  where  cavities  were  to  begin,  his  idea 
being  that  it  was  caused  by  "decomposition."  This  theory  was  of 
course  vague  as  to  the  real  active  agent  of  caries,  but  it  was  correct 

119 


I20  DENTAL    CARIES. 

in  the  principle  that  it  was  localized  at  certain  points  and  was  not 
general  in  the  fluids  of  the  mouth.  There  was  much  conjecture  about 
the  whole  question  of  the  active  agent  of  caries  till  Professor  W.  D. 
Miller  demonstrated  in  1884,  that  it  was  due  to  the  formation  of  acid 
brought  about  by  micro-organic  growth  in  the  mouth.  The  findings 
of  Miller  have  stood  the  test  of  investigation  since  then,  and  while 
there  are  many  factors  in  the  development  of  this  disease  which  we 
do  not  yet  quite  understand,  still  they  gave  us  the  first  real  basis  of 
scientific  knowledge  to  work  from. 

In  a  somewhat  close  clinical  observation  of  the  behavior  of  caries, 
the  variation  in  its  manner  of  attack,  and  in  its  general  modus  operandi 
in  different  cases,  it  is  hard  to  conceive  that  it  is  always  brought  about 
in  the  same  way  or  that  its  progress  is  invariably  governed  by  the  same 
conditions.  That  an  acid  causes  the  solution  of  the  tooth  tissue  seems 
settled,  and  that  this  acid  is  the  product  of  micro-organisms  is  also  an 
apparently  accepted  fact.  But  why  is  it  that  we  find  such  a  variation 
in  the  manifestations  of  the  disease  in  different  mouths,  and  even  in 
different  periods  in  the  same  mouth?  We  may  find  micro-organisms 
in  all  mouths — in  fact  the  very  micro-organism  which  Miller  demon- 
strated would  bring  about  decay,  and  decay  which  could  not  be  dis- 
tinguished from  that  occurring  in  teeth  in  the  mouth — and  yet  there  are 
some  mouths  in  which  decay  never  occurs,  and  in  most  mouths  where 
it  does  occur  there  is  a  great  variation  in  its  virulency  at  different  times. 

It  was  formerly  the  prevalent  idea  that  these  variations  were  due 
to  differences  in  the  tooth  structure,  that  one  tooth  was  harder  than 
another  and  would  therefore  withstand  the  attack  of  the  carious  agent 
better,  and  this  impression  was  so  strong  in  the  profession  that  it 
finally  communicated  itself  to  the  laity  and  is  still  firmly  fixed  in  their 
minds.  It  is  common  to  hear  patients  say  that  their  teeth  are  so  soft 
that  it  is  almost  impossible  to  save  them,  or  on  the  other  hand  that 
they  are  growing  harder  so  that  they  do  not  have  so  much  trouble 
with  them  as  formerly.  This  has  been  a  most  difficult  fallacy  to 
dislodge  from  the  minds  of  the  profession,  and  it  has  been  the  means 
of  the  loss  of  a  very  great  number  of  teeth  which  otherwise  might  have 
been  saved.  The  impression  that  the  teeth  are  inherently  so  defective 
in  structure  that  they  are  thereby  peculiarly  susceptible  to  the  attack 
of  caries  is  very  disheartening,  and  it  has  led  many  patients  to  abandon 
any  effort  to  save  them  and  to  allow  them  to  go  by  default.  This 
impression  has  too  frequently  been  fostered  by  members  of  the  pro- 
fession, whose  function  as  teachers  of  the  public  should  have  made 
them  guard  against  such  false  and  harmful  doctrine. 


DENTAL    CARIES.  121 

It  is  now  more  than  ten  years  since  the  investigations  of  Dr.  G.  V. 
Black  demonstrated  conclusively  that  there  is  really  little  variation 
in  the  chemical  constituents  of  the  teeth  of  different  individuals,  and 
that  what  variation  there  is  has  little  or  nothing  to  do  with  the  inception 
of  dental  caries.  This  came  as  almost  a  revolutionary  statement 
at  the  time  but  his  findings  have  never  been  disproved.  Neither  do 
the  teeth  of  individuals  grow  harder  and  softer  in  any  such  sense  as 
would  account  for  the  variations  we  see  in  the  same  mouth  in  the 
tendency  to  decay  at  different  periods.  Teeth  grow  slightly  harder 
as  age  advances  but  this  change  is  exceedingly  slow  and  not  of  a 
character  to  affect  the  manifestations  of  caries.  This  is  readily  under- 
stood when  we  recall  the  fact  that  the  teeth  are  the  most  stable  organs 
of  the  human  body,  and  are  not  being  constantly  torn  down  and  built 
up  by  w^aste  and  repair  as  are  other  tissues. 

And  yet  the  impression  in  the  profession  that  some  teeth  were 
very  much  harder  than  others  was  a  perfectly  natural  one,,  owing  to 
the  difference  in  behavior  of  teeth  under  cutting  instruments.  This 
difference  could  not  escape  the  attention  of  the  most  careless  observer. 
Some  teeth  crumble  away  under  chisels,  excavators  and  burs,  as  if 
composed  mostly  of  chalk;  while  others  resist  the  attack  of  steel  instru 
ments  almost  to  the  point  of  striking  fire.  This  led  to  the  impression 
of  varying  softness  and  hardness  in  the  teeth,  and  quite  naturally  to 
the  conviction  that  this  had  a  direct  bearing  on  the  tendency  to  decay. 
But  there  is  another  reason  to  account  for  the  difference  in  behavior 
of  teeth  under  instrumentation,  and  it  is  in  accordance  with  close 
clinical  observation  that  these  same  so-called  "soft"  teeth  sometimes 
remain  in  the  mouth  for  life  free  from  caries  while  the  "hard"  teeth 
as  frequently  decay.  It  simply  resolves  itself  down  to  a  question  of 
environment — the  conditions  which  surround  the  teeth — rather  than 
to  the  organic  structure  or  constituents  of  the  teeth  themselves. 

The  reason  that  teeth  vary  in  their  resistance  to  cutting  instru- 
ments is  limited  almost  wholly  to  the  enamel  and  is  due  chiefly  to  the 
arrangement  of  the  enamel  rods.  In  some  teeth  the  rods  stand  nearly 
parallel  and  radiate  outward  in  regular  order  from  the  dentin  in  a 
comparatively  straight  line.  It  is  noteworthy  that  in  any  enamel 
the  cement-substance  which  holds  the  rods  together  is  not  very  strong 
and  the  enamel  is  easily  cleaved  in  line  with  the  rods.  It  will  thus  be 
seen  that  straight-grained  enamel  like  this  will  break  down  readily 
under  instruments.  But  there  is  other  enamel  in  which  the  rods 
pursue  a  wavy  course,  and  a  section  of  which  looks  something  like 
the  structure  of  a  gnarled  oak.     When  a  chisel  is  directed  against 


122  DENTAL    CARIES. 

such  enamel  as  this  it  meets  the  stout  lateral  resistance  of  the  rods 
themselves  and  is  broken  down  with  exceeding  difficulty. 

But  there  is  no  enamel  formed  in  the  mouth  of  man  which  the  acid 
of  decay  is  not  capable  of  dissolving  if  the  conditions  are  favorable 
to  its  development,  and  so  all  enamel  is  alike  subject  to  the  attack  of 
caries.  This  one  difference  may  be  noted  that  when  decay  has  once 
begun  it  is  reasonable  to  suppose  that  it  will  progress  more  rapidly  in 
enamel  where  the  rods  stand  straight  so  that  the  acid  can  have  ready 
entrance  between  them  than  it  will  in  wavy  enamel  where  the  access 
is  less  easy,  though  this  has  no  relation  to  the  question  of  the  liability 
of  the  teeth  to  the  original  inception  of  caries. 

If,  then,  it  is  a  matter  of  the  conditions  surrounding  the  teeth  which 
chiefly  influences  this  disease,  it  is  imperative  that  we  study  these 
conditions  somewhat  carefully,  and  herein,  be  it  said,  lies  the  future 
hope  of  the  profession  in  controlling  and  ultimately  in  preventing  a 
disease  which  is  acknowledged  as  being  the  most  prevalent  of  all 
diseases  of  the  human  race.  Had  it  been  a  question  of  the  tooth 
structure  there  would  have  been  small  hope  because  we  have  learned 
that  when  once  developed  we  cannot  change  that,  but  being  a  question 
of  condition  we  may  reasonably  expect  in  time  to  so  control  the  sur- 
rounding condition  as  to  limit  the  disease. 

First  it  is  necessary  to  learn  what  the  conditions  are  which  influence 
the  inception  of  decay.  We  have  said  that  the  micro-organism  of 
caries  may  be  found  in  all  mouths;  then  the  natural  query  is,  why  do 
we  not  find  decay  in  all  mouths?  What  is  the  particular  agency  which 
makes  it  possible  for  the  micro-organism  to  bring  about  caries  in  one 
case,  and  impossible  in  another?  Dr.  J.  Leon  Williams,  and  Dr.  G. 
V.  Black  have  called  attention  to  what  they  consider  an  important 
factor  in  the  institution  of  caries,  viz.,  the  formation  of  gelatinous 
plaques  on  the  surfaces  of  the  teeth.  We  know  that  there  are  certain 
micro-organisms  which  in  the  process  of  their  development  produce 
a  material  closely  allied  in  appearance  to  gelatin,  and  these  are  called 
gelatin-forming  micro-organisms.  The  micro-organism  of  caries  is 
one  of  this  class,  and  it  is  the  opinion  of  Williams  and  Black  that  it  is 
mainly  through  the  agency  of  these  plaques  that  cavities  are  formed. 

It  is  of  course  known  that  an  acid  in  order  to  dissolve  enamel  in 
the  way  we  see  it  in  the  mouth  must  be  a  strong  acid,  and  unless  the 
micro-organisms  have  some  protection  under  which  to  work,  their  acid 
would  be  diluted  very  quickly  in  the  fluids  of  the  mouth,  and  thus  their 
destructive  process  be  interfered  with.  It  is  therefore  the  idea  of  these 
investigators  that  it  is  by  virtue  of  the  protection  given  the  micro- 


DENTAL    CARIES.  1 23 

organisms  through  the  formation  of  gelatinous  plaques  that  the  begin- 
nings of  decay  are  brought  about.  A  film  is  formed  on  the  surface 
of  the  enamel  and  under  cover  of  this  the  micro-organism  may  produce 
its  acid  in  concentrated  form  and  attack  the  enamel  undisturbed  by 
external  interference.  In  fact  Dr.  Williams  has  been  able  to  make 
ground  sections  of  teeth  thin  enough  for  microscopical  examination, 
showing  the  film  in  place  with  rhe  micro-organisms  under  it  and  decay 
beginning  in  the  enamel.  Of  course,  after  a  cavity  has  once  been  started 
the  micro-organisms  have  a  sheltered  place  in  which  to  work  and  do 
not  need  this  gelatinous  protection,  but  it  is  in  the  inception  of  caries 
that  it  plays  an  important  role.  This  film  is  not  soluble  in  the  fluids 
of  the  mouth  nor  is  it  easily  dislodged  when  firmly  attached.  No 
rinsing  of  the  mouth  with  liquid  will  affect  it,  and  it  takes  appre- 
ciable friction  with  a  tooth  brush  to  dislodge  it.  The  saliva  may 
therefore  flow  freely  over  its  surface  without  disturbing  it,  and  even 
the  most  potent  of  the  mouth  washes  yet  devised  will  not  dissolve  it. 

In  this  view  of  the  case  it  is  concluded  that  the  significant  thing 
in  dental  caries  is  the  formation  of  this  film,  and  that  it  is  really  the 
controlling  factor  in  the  question  of  immunity  and  susceptibility. 
In  some  mouths  the  conditions  seem  favorable  for  the  production  of 
these  plaques,  in  others  not,  and  upon  this  the  issue  is  turned.  In 
referring  to  plaques  it  must  be  remembered  that  a  distinction  should 
be  made  between  these  gelatinous  plaques  and  patches  of  inspissated 
mucus  and  greasy  masses  of  material  left  adherent  to  the  surface  of 
enamel  through  neglect  in  caring  for  the  teeth. 

Dr.  W.  D.  Miller  in  writing  on  this  subject  seems  to  place  less 
significance  on  the  film  than  Williams  and  Black,  and  claims  that  the 
case  is  not  yet  proven.  He  says  that  we  may  find  these  films  freely 
in  mouths  where  there  is  no  decay,  and  that  we  may  also  find  cavities 
without  the  presence  of  a  film.  In  the  latter  instance  he  admits  that 
the  absence  of  a  film  after  a  cavity  has  started  is  no  evidence  that  it 
may  not  have  been  there  in  the  beginning. 

In  point  of  fact  we  have  had  just  sufficient  knowledge  on  this  sub- 
ject to  make  it  imperative  that  we  have  more.  As  has  already  been 
intimated  the  behavior  of  some  cavities  is  so  entirely  different  from 
that  of  others  that  it  is  hard  to  conceive  that  they  are  all  influenced 
by  the  same  factors,  and  it  is  hoped  that  further  investigations 
along  these  lines  will  give  us  a  broader  view  of  the  whole  question, 
and  clear  up  some  of  the  points  which  at  present  seem  somewhat 
clouded. 

But  what  concerns  us  most  at  this  time  are  the  clinical  manifes- 


124  DENTAL    CARIES. 

tations  of  immunity  and  susceptibility  as  we  meet  them  in  our  every 
day  practice.  Dr.  Michaels  of  Paris  in  studying  the  manifestations 
of  susceptibility  and  immunity,  took  the  ground  that  they  were  largely 
influenced  by  the  condition  of  the  fluids  of  the  mouth,  and  claimed 
that  in  all  cases  of  high  susceptibility  to  dental  caries  there  was  a 
superabundance  of  ammonium  salts  in  the  saliva  and  an  absence  of 
sulpho-cyanatcs,  while  in  immune  mouths  there  was  a  diminution  or 
an  absence  of  ammonium  salts  with  the  presence  of  sulpho-cyanates. 
More  recently  Dr.  F.  W.  Low  of  Buffalo,  N.  Y.  has  practically  con- 
firmed Michaels'  findings,  and  goes  one  step  further  in  an  effort  to 
control  the  tendency  to  caries.  In  cases  of  great  susceptibility  he 
has  been  administering  the  sulpho-cyanates  to  patients  with  what 
seems  to  promise  success  in  arresting  the  tendency  to  decay.  It  is 
hoped  that  these  investigations  will  lead  to  something  definite  in  the 
way  of  controlling  this  disease.  A  close  observation  of  the  phenomena 
of  caries  in  the  average  susceptible  mouth  will  disclose  the  fact  that 
there  are  certain  times  when  the  disease  is  much  more  active  than 
others.  The  periodicity  of  dental  caries  may  be  studied  with  much 
profit  by  the  dentist,  with  the  result  that  he  is  better  equipped  to 
manage  the  cases  that  come  to  him  and  more  encouraged  to  persevere 
in  the  face  of  an  apparently  hopeless  condition  where  the  active  agent 
of  caries  seems  to  be  running  rampant  over  the  entire  number  of  teeth 
in  a  given  mouth. 

It  is  very  rare  indeed  where  the  progress  of  this  disease  goes  on 
uninterruptedly  to  the  destruction  of  all  the  teeth  in  a  mouth  even 
when  no  attempt  is  made  to  arrest  it,  and  much  rarer  in  the  event  of 
any  effort  being  put  forth  on  the  part  of  the  dentist  and  the  patient 
toward  its  control.  That  this  is  true  is  sufficiently  evident  from  the 
large  number  of  cases  seen  in  practice  where  some  of  the  teeth  have 
been  lost  many  years  previously  while  the  rest  are  being  preserved 
with  very  little  tendency  to  decay.  The  lesson  of  this  is  that  if  we  can 
carry  a  case  through  a  period  of  great  liability  to  decay  we  may  reason- 
ably expect  a  period  of  immunity  to  come  sooner  or  later  and  with 
this  to  aid  us  in  our  efforts  we  may  confidently  hope  to  save  the  teeth 
for  a  lifetime  so  far  at  least  as  decay  is  concerned. 

One  very  significant  fact  in  this  connection  is  worthy  of  especial 
note — a  fact  embodying  the  greatest  encouragement  and  carrying 
with  it  the  highest  incentive  to  persistent  and  painstaking  effort  on 
the  part  of  the  dentist.  This  is  the  assurance,  established  by  a  very 
close  clinical  observation  in  the  study  of  cases  extending  over  many 
years,  that  the  period  of  immunity  may  be  advanced  very  materially 


DENTAL    CARIES.  1 25 

by  proper  dental  service  at  the  time  of  greatest  susceptibility.  In 
other  words  when  a  dentist  is  struggling  with  a  discouraging  case  of 
caries,  endeavoring  to  keep  the  teeth  free  from  deposits  and  insisting 
that  the  patient  does  his  part  in  this  work,  when  he  is  filling  cavities 
which  develop  with  disheartening  frequency  and  repairing  fillings 
that  have  failed,  he  may  be  assured  that  the  result  of  his  efforts  does 
not  stop  with  the  teeth  he  is  operating  on,  but  that  in  his  attempt 
to  suppress  decay  he  is  changing  the  conditions  in  this  mouth  and 
establishing  a  state  of  immunity  which  will  eventually  aid  him  materi- 
ally in  saving  the  teeth  of  his  patient.  With  this  view  of  the  case  no 
dentist  should  lightly  yield  up  decaying  teeth  to  the  forceps,  nor  should 
he  become  discouraged  however  prevalent  decay  may  be  in  the  mouth. 
There  are  exceptions  to  all  rules  in  practice,  and  there  are  some  mouths 
in  which  the  tendency  to  caries  seems  to  persist  for  a  disheartening 
length  of  time,  but  in  the  average  case  the  results  are  so  very  gratifying 
that  it  is  well  worth  the  effort  of  both  operator  and  patient  to  follow 
up  a  line  of  treatment  tending  to  its  suppression. 

Recent  investigations  of  such  men  as  J.  Sim  Wallace,  and  H.  P. 
Pickerill  would  seem  to  indicate  that  the  matter  of  diet  'is  a  very 
important  factor  in  controlling  dental  decay.  Wallace  after  a  close 
study  of  the  effect  of  diet  on  dental  decay  emphasizes  the  necessity 
of  a  diet  containing  fibrous  foods  which  stimulate  efl&cient  mastication; 
and  sums  up  his  observations  by  outlining  two  diets,  one  of  which  is 
supposed  to  inhibit  decay  and  the  other  to  encourage  it.  In  his  book 
"The  Prevention  of  Dental  Caries,"  page  32,  he  says: 

Firstly,  we  shall  refer  to  the  kind  of  meals  which  do  not  produce 
caries : — 

Breakfast. — Fish,  bacon,  toast  and  butter,  coffee  and  tea. 

Luncheon. — Meat  or  poultry,  potatoes,  salad,  baked  bread,  pud- 
ding, fresh  fruit,  water. 

Supper. — Rusks,  toast,  or  bread,  rolls  and  butter,  chicken  or  fish, 
an  apple,  tea  or  coffee. 

Secondly,  we  may  outline  the  kind  of  meals  which  induce  dental 
caries : — 

Breakfast. — Porridge  and  milk,  bread  and  marmalade.  Then 
perhaps  a  supplementary  breakfast  a  few  hours  after  of  a  glass  of 
milk  and  a  sweet  biscuit. 

Luncheon. — Mashed  potatoes  and  gra\7,  or  minced  meat,  milk 
and  pudding. 

Supper. — Bread  soaked  in  milk,  or  bread  and  jam,   cocoa  and 


126  DENTAL   CARIES. 

cake,  and  a  supplementary  supper  on  going  to  bed  of  a  glass  of  milk 
and  biscuit,  or  just  a  'tiny  piece  of  chocolate.' 

"On  comparing  these  two  different  types  of  diet,  we  observe  that 
one  is  of  a  kind  which  stimulates  mastication  and  the  last  thing  taken 
leaves  the  mouth  clean,  or  at  least  free  from  carbohydrates,  so  that 
even  when  soft  food  is  part  of  the  meal  the  mouth  will  be  physiolog- 
ically clean  at  the  end  of  the  meal.  The  other  type  is  intended  to 
represent  the  other  kind  of  meal  which  is  calculated  to  lodge  about 
the  teeth  and  to  ruin  them  in  a  few  years  by  making  efficient  masti- 
cation and  the  self-cleansing  of  the  mouth  practically  impossible,  and 
by  leaving  the  mouth  sticking  with  fermentable  carbohydrates  and  a 
virulent  crop  of  acid-forming  micro-organisms  which  have  had  their 
development  encouraged  by  the  previous  meal." 

Pickerill  in  his  book  "The  Prevention  of  Dental  Caries  and  Oral 
Sepsis,"  lays  great  stress  on  the  advantage  of  articles  of  diet  which 
may  be  classed  as  "Salivary  Stimulants."  To  develop  a  condition  of 
the  saliva  inimical  to  the  incidence  of  caries  it  is  necessary  to  use  acids 
in  the  diet,  a  seemingly  strange  phenomenon  but  one  apparently  borne 
out  by  fact.     He  says: 

"What  is  therefore  to  be  advocated  is  that  all  meals  should  con- 
tain a  fair  proportion  of  salivary  excitants,  and  more  important  still, 
should  both  commence  and  end  with  some  article  of  diet  having  an  acid 
reaction  r 

This  teaching  of  Professor  Pickerill  is  almost  revolutionary  so  far 
as  popular  opinion  is  concerned.  It  has  always  been  the  prevalent 
opinion  that  the  eating  of  acid  substances  was  detrimental  to  the  teeth, 
and  yet  Pickerill  proves  that  the  mastication  of  acid  fruits  puts  the 
secretions  of  the  mourh  in  the  best  possible  condition  to  combat 
caries. 

His  suggestion  as  to  diet  is  as  follows: — 

Breakfast. — Porridge  with  salt  may  be  used,  followed  by  any- 
thing customary,  fish,  bacon,  bread  and  butter,  marmalade  or  jam, 
the  latter  should  be  of  a  distinctly  acid  flavor.  Conclude  with  some 
form  of  fresh  fruit,  orange,  apple,  pineapple,  banana,  pear,  plum,  etc., 
preferably  raw,  but  may  be  stewed. 

Luncheon. — A  radish  or  small  portion  of  some  acid  fruit  as  an 
initial  salivary  stimulant,  meat,  with  sauces,  which  are  nearly  all  acid 
and  serve  as  excellent  salivary  stimulants.  Fruit  (stewed)  and  fruit 
pudding  or  pie,  made  not  too  sweet,  and  fruit  predominating  over  the 
starch  element.     Salad.* 

Tea. — May  include  as  salivary  stimulant,  tomato,  cucumber,  cress, 


DENTAL    CARIES.  1 27 

sardines,  shrimps,  fruit  or  sandwiches.     Fruit  salad  or  any  fruit  in 
season  should  terminate  the  meal. 

Last  thing  at  night  children  (and  adults,  too)  should  always  eat 
a  small  portion  of  some  detergent  and  acid  fruit,  such  as  orange,  apple, 
pear,  or  pineapple.  Tea  and  coffee,  with  cake,  biscuits,  etc.,  are  not 
good  as  terminations  to  any  meal.  Milk,  water,  weak  lime  and  lemon 
juice,  slightly  sweetened,  are  the  beverages  suited  for  children." 

The  testing  out  of  all  these  theories  requires  time,  but  the  efforts 
of  earnest  men  all  working  to  the  same  end  must  eventually  result 
in  a  reasonable  control  of  this  disease. 

The  period  of  greatest  susceptibility  to  dental  caries  is  in  youth, 
and  it  is  here  that  our  best  endeavor  in  controlling  decay  should  be 
put  forth.  If  we  can  successfully  save  the  teeth  to  the  twenty-fifth 
year  the  worst  of  the  difficulty  is  over,  except  that  in  mouths  where 
there  has  been  great  susceptibility  we  may  look  for  occasional  relapses 
even  where  a  condition  of  comparative  immunity  has  been  established. 
The  circumstances  which  bring  about  these  relapses  are  not  always 
apparent  and  it  is  sometimes  difficult  to  account  for  them.  Anything 
which  changes  the  conditions  of  the  mouth  may  do  it,  such  as  a  pro- 
tracted illness,  a  change  of  climate  which  involves  an  entirely  new 
environment,  or  any  radical  difference  in  the  mode  of  life,  or  dis- 
turbance of  the  functional  equilibrium  of  the  individual.  Severe  men- 
tal stress  is  known  to  frequently  induce  an  active  recurrence  of  caries 
in  a  mouth  which  has  for  years  been  immune.  But  usually  if  a  re- 
lapse comes  it  is  easily  controlled  and  not  nearly  so  severe  as  the  origi- 
nal attack. 

This  reference  to  the  original  attack,  the  relapses,  and  the  periods 
of  immunity  does  not  imply  that  there  is  a  sharp  line  of  demarcation 
between  them.  An  occasional  cavity,  or  cavities,  may  develop  at 
any  time,  but  there  is  a  very  great  difference  between  this  and  the 
awful  havoc  which  we  see  so  often  occurring  during  periods  of  great 
susceptibility.  Neither  does  it  follow,  when  we  get  a  set  of  teeth  in 
good  condition  after  susceptibility,  that  there  will  be  no  further  need 
of  dental  service,  even  though  the  mouth  should  remain  immune. 
Where  decay  has  once  manifested  itself  extensively  in  a  mouth  the 
teeth  should  have  the  supervision  of  a  dentist  at  regular  intervals 
afterward.  There  is  always  the  necessity  for  hygienic  treatment 
in  the  way  of  removing  deposits  and  general  prophylaxis,  besides  the 
repairs  so  frequently  required  in  the  operations  performed  during 
susceptibility.  In  a  delicate  child  during  the  growing  period  if  the 
teeth  decay  rapidly  it  is  not  always  possible  to  do  permanent  work, 


128  DENTAL    CARIES. 

and  we  may  carry  the  teeth  to  the  twentieth  or  even  twenty-fifth  year 
and  have  the  formation  of  new  cavities  practically  stopped,  but  with 
the  necessity  before  us  of  making  more  permanent  operations  as  the 
other  ones  fail  from  time  to  time.  It  is  always  best,  of  course,  to  make 
permanent  operations  in  the  beginning  if  this  is  possible,  but  it  is 
not  always  possible  with  some  of  the  temperamental  conditions  we 
meet  in  practice. 

To  carry  one  of  these  young  mouths  through  the  susceptible  period 
is  often  very  trying  but  the  result  is  well  worth  the  effort.  The  plan 
of  procedure  should  be  about  as  follows:  When  a  child  is  brought 
to  the  dentist  with  the  teeth  decaying  rapidly  there  should  be  no  half- 
hearted measures  or  perfunctory  attention  to  the  work.  It  is  not 
merely  a  matter  of  filling  cavities,  though  this  of  course  should  be  done 
at  once,  and  done  as  thoroughly  as  the  circumstances  will  permit. 
But  what  is  of  equal  consequence  is  that  a  campaign  of  prophylaxis 
be  instituted  with  the  definite  aim  of  limiting  the  disease  as  far  as 
possible  in  the  future.  The  child  should  be  schooled  into  a  system 
of  caring  for  the  teeth  by  such  an  impressive  lesson  from  the  dentist 
that  it  cannot  well  go  unheeded,  and  there  should  be  a  regular  inspec- 
tion of  the  teeth  by  the  practitioner  to  see  that  proper  care  is  being 
given  them,  and  that  normal  function  is  maintained.  The  key-note 
to  the  whole  situation  is  the  alteration  of  existing  conditions  in  the 
mouth,  and  while — as  has  already  been  intimated — we  do  not  know 
all  we  should  about  the  conditions  which  influence  this  disease,  yet 
we  are  certain  of  one  thing  that  the  establishment  of  full  functional 
activity  is  favorable  to  the  limitation  of  the  disease.  To  this  end  all 
teeth  should  be  kept  comfortable  for  mastication,  and  wherever  we 
find  evidences  that  mastication  is  not  being  properly  performed  we 
should  discover  the  cause  and  remedy  it.  A  close  observer  can  always 
tell  whether  or  not  the  teeth  and  gums  are  subjected  to  the  amount 
of  friction  necessary  for  perfect  mastication  by  noting  the  unpolished 
surfaces  of  the  teeth  and  the  hypertrophied  and  congested  condition 
of  the  gums,  and  where  it  seems  impossible  to  establish  the  habit  of 
good  mastication  in  any  given  case,  or  in  any  particular  region  of  a 
mouth,  the  child  should  be  instructed  to  make  up  the  deficiency  by 
friction  of  the  brush  for  a  stated  period  of  time  each  day.  The  time 
should  be  set  by  the  dentist,  and  the  patient  urged  to  brush  by  the 
watch.  The  friction  of  the  brush  moistened  in  cold  water  over  the 
teeth  and  gums  for  three  consecutive  minutes  twice  a  day  will  soon 
have  a  very  appreciable  effect  in  stimulating  the  tissues  to  healthy 
action,  and  in  polishing  the  enamel  smooth  and  bright. 


DENTAL   CARIES.  1 29 

Cavities  should  be  filled  as  fast  as  they  occur,  the  aim  being  to 
keep  caries  out  of  the  mouth  at  all  hazards.  Sometimes  the  disease 
is  so  rampant  that  it  is  difficult  to  maintain  the  courage  of  the  patient, 
and  yet  such  a  case  should  be  fought  with  all  the  energy  and  enthusiasm 
of  the  operator,  to  the  end  that  he  inspires  the  patient  with  the  con- 
fidence of  ultimate  success.  Such  patients  should  be  carefully  schooled 
in  the  theory  of  an  approaching  immunity,  and  the  operator  who  is 
in  earnest  in  his  management  of  the  case  may  conscientiously  promise 
this  on  the  basis  of  what  has  been  observed  in  a  close  clinical  study 
of  such  cases.  There  is  a  reasonable  expectancy  that  in  ninety-nine 
cases  out  of  one  hundred  the  teeth  can  be  saved  if  proper  attention  is 
given  them,  and  the  usual  history  is  that  even  in  a  very  susceptible 
mouth  about  the  eighteenth  or  twentieth  year  the  conditions  begin  to 
clear  up  and  the  hardest  part  of  the  contest  is  over. 

It  is  true  that  teeth  are  sometimes  neglected  so  that  when  the  dentist 
is  finally  consulted — usually  as  the  result  of  pain — the  conditions  are 
so  bad  as  to  be  very  discouraging,  and  yet  there  is  no  case  so  hopeless 
where  sufficient  of  the  tooth  is  left  as  a  basis  for  a  filling,  inlay  or 
crown  that  the  dentist  should  let  it  go  by  default.  It  is  the  lack  of  an 
enthusiastic  application  on  the  part  of  the  dentist,  a  failure  to  show 
forth  an  evident  confidence  in  the  possibility  of  saving  the  natural 
teeth,  and  the  neglect  to  sufficiently  emphasize  the  importance  of 
retaining  them  that  has  led  many  patients  both  in  youth  and  middle 
life  to  become  unappreciative  of  their  real  value,  and  indifferent  as  to 
their  care. 

The  dentist  may  not  be  able  as  has  already  been  intimated  with 
our  present  knowledge  to  treat  the  mouth  medicinally  so  as  to  change 
a  susceptible  case  to  one  of  immunity,  but  he  assuredly  can  by  insti- 
tuting the  proper  line  of  prophylactic  and  operative  procedures  so 
influence  the  conditions  as  to  at  least  control  the  disease  and  ultimately 
save  the  teeth.  Not  only  this  but  he  can  by  pursuing  the  proper  course 
in  the  management  of  these  cases  so  advance  the  period  of  immunity 
from  generation  to  generation  as  eventually  to  limit  the  disease  and 
bring  it  under  easy  control.  It  is  frequently  noted  now  that  even 
where  the  deciduous  teeth  are  extensively  affected,  if  proper  attention 
is  given  to  the  case  the  conditions  are  so  changed  that  there  is  little 
tendency  to  decay  of  the  permanent  teeth,  and  they  may  be  saved 
without  much  demand  for  filling. 

The  future  hope  of  the  profession  is  in  the  study  of  conditions 
which  exist  in  the  mouth,  and  while  the  ability  to  properly  perform 
operations  is  exceedingly  important  it  is  not  more  so  than  a  close 
9 


I30 


DENTAL   CARIES. 


observation  of  the  phenomena  which  influence  disease  and  also  which 
affect  materially  the  outcome  of  our  technical  procedures.  If  we 
understand  conditions  we  shall  operate  more  skillfully,  more  intel- 
ligently, and  the  result  of  our  work  will  redound  to  the  greater  credit 
of  the  profession  and  a  more  lasting  benefit  to  those  who  place  them- 
selves under  our  care. 


CHAPTER  VII. 

EXAMINATION  OF  TEETH  FOR  THE   DISCOVERY 
OF  CARIOUS  CAVITIES. 

BY    GARRETT   NEWKIRK,    M.D. 

The  practice  of  medicine  in  all  of  its  departments  may  be  com- 
prehended in  two  great  divisions:  First,  diagnosis — finding  out  what 
is  the  matter;  second,  the  choice  and  application  of  remedies. 

Physical  exploration  of  the  teeth  for  the  discovery  of  caries  might 
be  styled  mechanical  diagnosis.  It  should  be  as  carefully  and  thor- 
oughly made  as  an  examination  by  the  physician  for  the  diagnosis 
of  disease.  While  it  is  not  all  of  dentistry  to  discover  carious  con- 
ditions, and  prepare  and  fill  cavities,  these  constitute  the  larger  part 
of  its  employment. 

Every  one  who  comes  to  the  dentist  for  consultation  and  advice 
is  entitled  at  once  to  a  thorough  examination  of  his  teeth.  He  has 
a  right  to  expect  that  no  carious  spot  shall  remain  undiscovered. 
Every  continuing  patient  should  have  such  an  examination  at  regular 
periods,  and  should  be  notified  of  the  time  if  he  fails  to  remember  it. 
Examinations  at  stated  periods  are  of  the  greatest  importance  with 
young  people.  They  should  be  made  in  all  cases  at  least  twice  each 
year;  as  a  general  rule  once  in  three  months;  with  some  children, 
under  special  conditions,  oftener. 

A  systematic  record  should  be  made  not  only  of  conditions  requiring 
operations  soon,  but  of  those  which  threaten  danger  at  some  future  time. 

REGIONAL  DIVISIONS  FOR  EXAMINATION. 

First. — Those  pertaining  to  lines  of  union  (so  apt  to  be  imperfect) 
between  the  enamel  plates,  on  the  occlusal  surfaces  of  bicuspids  and 
molars,  the  lingual  aspect  of  upper  incisors,  and  in  the  buccal  or  lingual 
grooves  of  molars. 

Second. — Gingival — regions  bordering  or  beneath  the  gum  tissue 
particularly  those  upon  the  labial  and  buccal  surfaces  from  the  central 
incisors  to  the  last  molars. 

Third. — Proximal — those  surrounding  and  including  the  contact 
points  of  the  teeth,  particularly  the  surfaces  immediately  rootward  from 
those  points. 

131 


132     EXAMINATION  OF  TEETH  FOR  DISCOVERY  OF  CARIOUS  CAVITIES. 

Fourth. — Marginal — along  the  lines  of  former  operations,  at  the 
edges  of  fillings  and  crowns. 

SYSTEM  AND  METHOD. 

There  should  be  a  regular  system  of  examination  and  a  particu- 
lar method  of  marking  diagrams.  The  writer  has  adopted  the  follow- 
ing rules.  The  lower  teeth  are  examined  first,  with  the  patient  in  a 
position  nearly  erect,  so  that  when  the  mouth  is  opened  the  light  from 
the  window  falls  directly  upon  the  field  of  observation. 

Examination  begins  with  the  central  incisor  and  proceeds  to  the 
last  molar,  first  on  the  left,  then  on  the  right.  For  the  examination 
of  the  upper  arch  the  position  of  the  patient  is  higher  with  the  body 
and  head  inclined  backward,  so  that  as  before  the  teeth  meet  the  light 
fairly;  and  here  the  order  of  examination  is  the  same.  The  diagram 
blank  and  a  pencil  should  be  on  the  bracket  table,  and  a  record  made 
of  each  carious  or  suspected  point  immediately  upon  discovery. 

CONDITIONS  FOR  EXAMINATION. 

First,  Cleanliness. — The  first  procedure  for  an  examination  of 
the  teeth  is  to  clean  them.  Not  only  must  they  be  freed  from  calcareous 
deposits  but  as  far  as  possible  from  stains.  In  no  other  way  can  every 
surface  be  brought  to  view  and  imperfections  noted.  The  use  of  the 
scaler  will  often  reveal  points  of  sensitiveness  or  the  hidden  margin  of 
a  cavity.  One  should  never  pass  an  opinion  as  to  the  number  and 
extent  of  cavities,  or  the  probable  cost  of  operations,  till  he  has  been 
permitted  to  put  the  teeth  in  a  proper  condition  and  make  a  recorded 
examination. 

Dryness. — Cleanliness  of  surfaces  having  been  assured,  the  next 
precaution  necessary  is  freedom  from  moisture.  No  accurate  ex- 
amination can  be  made  of  a  wet  surface.  The  beginnings  of  decay 
are  seen  imperfectly  or  not  at  all  through  films  of  mucus  and  saliva. 

For  an  examination  of  the  upper  teeth  so  far  as  may  be  without 
the  use  of  the  dam,  a  cotton  roll,  or  strip  of  lintine,  or  a  thick  piece  of 
spunk  is  laid  between  the  alveolar  process  and  the  lip  or  cheek,  while 
the  patient  is  requested  to  keep  the  mouth  steadily  open. 

Freedom  from  moisture  for  a  corresponding  examination  of  the 
lower  teeth  is  not  easily  assured.  The  saliva  ejector,  valuable  in  all  cases, 
•  is  here  quite  indispensable.  If  the  operator  has  no  assistant  the  patient 
himself  may  render  service.  A  long  roll  of  cotton  or  muslin  is  held 
down  on  each  side  of  the  alveolar  ridge.  For  the  left  side,  assuming 
the  operator  to  be  right  handed,  he  will  hold  with  the  forefinger  of  his 


CONDITIONS    FOR    EXAMINATION.  1 33 

left  hand  the  roll  between  the  tongue  and  the  ridge,  the  assistant  (or 
patient)  holding  the  other  firmly  between  the  ridge  and  the  lip.  '  On 
the  right  side,  per  contra,  the  assistant  will  hold  the  roll  against  the 
lingual  side  of  the  alveolar  ridge,  the  operator  that  next  the  cheek. 

After  drying  the  teeth  with  spunk  and  warm  air  they  are  rubbed 
well  with  alcohol  on  cotton  and  dried  again.  Where  secretions  are 
specially  viscid  and  hard  to  remove  it  is  well  to  precede  the  alcohol 
with  pumice.  After  this  treatment  the  teeth  present  a  different 
appearance.  Pits  and  fissures  are  revealed  in  the  occlusal,  lingual 
and  buccal  surfaces;  also  shadows  and  color  spots  that  often  indicate 
proximal  decay. 

Having  obtained  dry  surfaces,  the  operator  with  a  good  eye,  sharp 
exploring  instrument  and  a  magnifying  mirror,  will  be  able  to  discover 
carious  spots  of  all  classes  save  one;  but  that  one  is  perhaps  the  most 
insidious  and  dangerous  of  all — the  decay  which  has  its  beginning 
close  to  and  directly  rootward  from  the  contact  point  of  a  tooth. 
These  are  the  decays  that  sometimes  penetrate  deeply  with  an  open- 
ing so  small  as  to  be  hardly  discoverable  by  the  finest  point  of  an 
instrument.  Unseen  and  unsuspected,  their  ravages  proceed  till  a 
large  extent  of  dentin  is  disorganized,  and  the  enamel  of  the  occlusal 
surface  is  so  undermined  that  it  breaks  down  suddenly  under  stress. 
These  are  the  cavities  that  patients  will  tell  us,  "Came  all  at  once," 
because  so  long  as  the  enamel  stood  over  the  chasm  there  was  nothing 
to  indicate  its  presence. 

A  common  practice  is  that  of  depending  on  the  evidence  of  thread, 
passed  between  the  teeth;  but  this  alone  is  not  conclusive.  By  the 
roughening  or  tearing  of  floss  silk  it  is  true  that  we  suspect  decay, 
though  the  rough  edge  of  a  filling,  or  tartar,  may  produce  the  same 
efifect.  But  the  free  passage  of  floss  is  not  conclusive  evidence  of  a  healthy 
condition.  The  surface  of  the  tooth  may  seem  perfectly  smooth  to  the 
thread  over  a  spot  of  unbroken,  dead  enamel  and  a  sepulcher  of  dentin. 
In  other  words  the  thread  will  show  us  plainly  very  often  where  decay 
is,  but  is  unreliable  for  determining  where  decay  is  not. 

The  only  conclusive  method  is  to  get  separation  for  vision  and 
instrumental  exploration.  Where  the  slightest  doubt  exists  as  to  the 
integrity  of  teeth  at  these  points,  the  rubber  dam  should  be  used  in 
association  with  the  mechanical  separator.  With  the  dam  in  position 
we  are  certain  of  dryness,  and  there  is  no  call  for  haste  in  the  examina- 
tion. From  four  to  six  teeth  may  be  included  at  once,  and  their 
proximal  surfaces  examined  in  succession. 

By  the  use  of  the  mechanical  separator,  sufficient  space  may  be 


134    EXAMINATION  OF  TEETH  FOR  DISCOVERY  OF  CARIOUS  CAVITIES. 

obtained  nearly  always  in  a  few  moments  for  a  decisive  exploration. 
A  bit  of  space  with  a  gleam  of  light  makes  a  world  of  difference  in  the 
field  of  observation.  Where  before  no  sign  of  decay  was  seen,  it  may 
be  that  a  speck  of  discoloration,  brown  or  whitish  will  appear.  A 
delicate  steel  point  finds  an  opening,  a  sharp,  thin  chisel  breaks  the 
enamel  roof,  and  the  excavator  possibly  reveals  a  deep  extension  of 
decay.  A  condition  such  as  this  we  have  no  right  to  overlook.  We 
should  know  positively,  either  that  it  does  or  does  not  exist.  We  have 
no  right  to  dismiss  an  examination  with  the  word  or  thought,  "I 
guess  that's  all  right."  It  is  our  business  to  know.  Opinions  fathered 
by  wishes  have  no  value. 

RECORDS  OF  EXAMINATION. 

The  dentist  should  keep  himself  supplied  with  pads  of  examination 
blanks  such  as  are  kept  in  stock  by  the  supply  houses.  Each  blank 
should  exhibit  a  diagram  of  the  teeth,  both  deciduous  and  permanent, 
with  lines  for  name  and  date. 

In  some  cases  it  is  well  to  make  the  first  record  tentative — pre- 
sumably incomplete.  Pursuing  the  methods  first  described,  the  teeth 
are  surveyed  as  thoroughly  as  may  be  without  the  employment  of  dam 
and  separator.  The  diagram  is  marked  for  every  cavity  and  fissure 
that  is  positively  indicated,  and  at  every  proximal  line  where  the  least 
uncertainty  exists  an  interrogation  point  ( ?)  is  placed. 

After  other  operations  have  been  concluded,  the  doubtful  spaces 
are  examined  one  by  one  with  the  aid  of  dam  and  separator.  If  there 
is  found  in  one  place  nothing  to  do,  well.  If  in  another  but  superficial 
decay,  it  is  polished  and  medicated  with  reference  to  the  adage,  "A 
stitch  in  time  saves  nine."  If  a  cavity  is  discovered,  separation  is 
increased  and  a  filling,  temporary  or  permanent,  introduced. 

When  all  this  is  done  the  operator  may  truly  feel  that  no  interest 
in  the  case  consigned  to  his  care  has  been  neglected. 

CONCLUDING  NOTES. 

Special  care  should  be  taken  to  examine  along  the  subgingival 
margins  of  gold  crowns,  especially  those  placed  over  teeth  with  living 
pulps,  where  the  right  preparation  could  not  have  been  made  and 
there  was  necessarily  an  ill  fitting  band.  Also  careful  exploration  should 
be  made  about  the  margins  of  Logan  and  other  bandless  crowns  for 
caries  that  may  have  begun  in  the  root.  For  a  complete,  visual 
examination  of  cavities  beneath  the  gingival  gum,  a  thin  bladed  retrac- 


CONCLUDING    NOTES.  I35 

tor  is  convenient,  and  often  it  is  necessary  to  control  hemorrhage  with 
carbolic  or  trichloracetic  acid  or  adrenalin  chloride. 

Failure  to  examine  for  decay  beneath  fillings  of  unfavorable  ap- 
pearance is  a  common  fault  and  followed  often  by  serious  consequences. 
The  dentist  is  apt  to  take  too  much  for  granted  as  to  conditions  beneath 
fillings  made  of  all  sorts  of  mixtures  that  have  gone  under  the  general 
name  of  amalgam.  We  should  not  be  prevented  by  a  false  conserva- 
tism from  thorough  examination  in  these  cases.  We  should  make 
doubly  sure  that  our  insidious  enemy,  caries,  does  not  "steal  a  march" 
on  us  in  the  tattered  uniform  of  a  friend. 

A  small  keen  hoe  or  hatchet  excavator  will  oftentimes  penetrate 
a  dead  enamel  wall  and  reveal  a  cavity  better  than  a  delicate  pointed 
explorer. 

No  service  rendered  by  the  dentist  should  entitle  him  to  better 
compensation  on  the  basis  of  time  than  that  involved  in  a  careful 
examination  of  the  teeth. 


CHAPTER  VIII. 

SEPARATION  OF  TEETH  PREPARATORY  TO 
OPERATING  ON  CAVITIES  IN  THE  PROX- 
IMAL SURFACES. 

BY    GARRETT    NEWKIRK,    M.  D. 

Restoration  is  the  watchword  of  operative  dentistry.  Simply  upon 
the  forms  of  the  teeth  depend  their  relations  one  to  another  and  to 
their  surrounding  tissues,  and  together  with  color,  their  appeal  to  the 
esthetic  sense. 

Among  the  many  considerations  necessary  in  the  restoration  of 
tooth  forms,  and  one  of  the  most  important,  is  that  of  the  interproximal 
space.  This  has  a  definite  relation  to  the  forms  and  contact  points 
of  the  teeth  involved.  For  the  first  adequate  study  and  presentation 
of  this  subject  the  profession  is  indebted  to  Dr.  G.  V.  Black,  through  a 
paper  read  by  him  before  the  Odontographic  Society  of  Chicago,  and 
published  in  the  Dental  Review,  1890.  Up  to  this  time  and  for 
many  years  previous  the  best  operators  had  often  advocated  the 
restoration  of  the  natural  forms  of  teeth  as  a  matter  of  idealism, 
but  none  had  grasped  the  subject  in  all  its  relations.  Dr.  Black  set 
forth  the  importance  of  a  normal  interproximal  space  for  the  conser- 
vation of  healthy  gum  tissue,  to  secure  the  best  conditions  of  cleanliness, 
to  prevent  the  lodgment  and  impaction  of  food,  to  allow  the  ready 
cleansing  of  the  adjacent  surfaces,  to  insure  in  large  measure  the 
permanence  of  fillings,  to  promote  the  comfort  of  the  patient  and 
satisfaction  of  the  operator — all  this  depending  of  necessity  on  the 
true  proximal  contour  of  the  teeth,  in  accordance  with  nature's  plan. 

Separation  for  dental  operations,  by  whatever  method,  has  for  its 
object  the  assistance  of  the  operator  in  the  restoration  of  tooth  forms, 
and  the  preservation  therewith  of  healthy  interproximal  gum  tissue. 
Without  separation  preparatory  to  filling,  it  is  impossible  to  secure  the 
necessary  contours. 

Separation  may  be  of  two  sorts,  first,  by  the  slow  pressure  of  some 
expansive  material  like  wood,  cotton,  linen  tape,  rubber  or  gutta- 
percha, continued  for  hours  or  days,  and  denominated  "previous;" 
second,  by  a  driven  wedge  or  one  of  the  mechanical  appliances,  coin- 
cident with  the  operation  of  filling  and  styled  the  "immediate." 

137 


138  SEPARATION    OF    TEETH. 

Both  'methods  are  valuable  and  necessary,  each  in  its  place.  As  a 
rule  the  previous  should  be  followed  by  the  immediate,  for  whatever 
space  has  been  obtained  beforehand  should  also  be  held  during  the 
several  stages  of  operative  procedure. 

PREVIOUS— SLOW  WEDGING. 

The  writer  will  say  at  the  outset  that  the  longer  he  continues 
in  practice  the  less  he  depends  on  very  slow  wedging  for  the  separation 
of  teeth.  He  is  more  fearful  than  formerly  of  inflicting  permanent 
injury  to  the  tissues  involved — viz.,  the  pericemental  membranes,  the 
interproximal  alveolar  wall,  and  the  over-lying  gums.  All  these 
tissues  will  endure  a  certain  amount  of  pressure  with  temporary  dis- 
placement, and  return  to  their  normal  positions  unharmed  when  the 
pressure  is  removed;  but  the  pressure  should  not  be  greater  nor  longer 
continued  than  is  absolutely  necessary  to  the  restoration  required. 
It  involves  primarily  the  question  of  blood  supply — a  diminution  here 
and  an  increase  there  within  the  various  parts  involved.  This  may  be 
illustrated  by  any  one  in  a  moment.  Place  the  ends  of  your  thumbs 
together  so  that  the  free  margins  of  the  nails  overlap.  Press  these 
one  upon  the  other  alternately  and  repeatedly,  and  watch  the  blood 
pressure  as  it  changes  beneath  each  nail,  the  red  and  the  white  coming 
and  going,  one  congested,  the  other  anemic.  This  is  precisely  what 
takes  place  in  the  tissues  surrounding  the  root  of  a  tooth  when  pressure 
is  brought  to  bear  for  separation.  Ere  long  if  pressure  is  not  relaxed 
absorption  begins.  It  follows,  therefore,  that  whenever  the  "im- 
mediate" method  of  separation  can  be  employed  judiciously,  it  is 
the  one  to  be  preferred. 

GUTTA-PERCHA. 

Slight,  non-irritating  separation  may  be  made  to  great  advantage 
in  many  cases  with  gutta-percha,  this  being  used  at  the  same  time  as  a 
temporary  stopping. 

As  we  know,  it  is  often  advisable,  sometimes  unavoidable,  that 
such  fillings  should  be  inserted  for  a  period  of  days  or  weeks.  In 
these  cases  it  is  possible  to  make  the  material  accomplish  the  double 
purpose  of  protection  and  separation.  By  the  use  of  considerable 
force  with  a  broadfaced  burnisher  as  the  material  slowly  hardens  in 
the  cavity,  it  may  be  so  compressed  as  to  make  it  elastic — like  rubber, 
only  in  smaller  measure.  The  effect  will  be  increased  if  the  gutta- 
percha is  inserted  while  the  teeth  are  held  slightly  apart  by  the  me- 
chanical separator,  which  should  be  kept  in  place  till  the  filling  is  cold. 
Then,  the  gutta-percha  answers  well  if  it  simply  holds  the  space 


COTTON.  1 39 

obtained  by  the  separator  till  the  next  sitting,  when  by  re-application 
of  the  instrument  the  space  may  be  increased,  probably  to  the  full 
extent  necessary. 

Gutta-percha  is  further  useful  as  a  separating  material  in  that 
the  gum  tissue  that  sometimes  overlaps  the  gingival  margin  of  a 
cavity  may  be  crowded  back  from  the  enamel  edge — or  from  the 
cemental  border  of  an  extruded  tooth — making  possible  a  clearer 
view  of  the  parts,  and  better  preparation  for  the  filling.  But  this 
must  be  done  with  extreme  care,  otherwise  serious  injury  may  be 
inflicted  by  over-pressure.  Years  ago  it  was  advised  by  some  to  leave 
the  fillings  much  over-full,  in  order  that  the  material  might  be  forced 
down  and  spread  by  the  cusps  of  the  occluding  teeth,  allowing  it  to 
remain  for  weeks  or  months.  In  some  instances  the  effects  of  this 
practice  were  disastrous.  The  interproximal  gum  tissue  was  injured 
or  destroyed,  and  articulation  of  the  teeth  seriously  interfered  with. 

Whenever  it  is  purposed  to  use  a  temporary  stopping  for  separa- 
tion, all  over-hanging  walls  should  be  vigorously  chiseled  away  and 
decayed  matter  removed  from  the  cavity,  both  for  medical  treatment 
and  to  give  a  firm  base  for  the  pressure  to  be  exerted.  And,  as  a 
rule,  it  pays  in  satisfaction  and  efficiency  to  use  the  rubber  dam. 

In  this  connection  it  seems  best  to  quote  a  paragraph  from  Dr. 
C.  N.  Johnson's  work  on  the  Principles  and  Practice  of  Filling  Teeth: 
"To  economize  time  in  the  management  of  these  cases,  it  is  well  for 
the  operator,  on  examining  a  mouth  where  several  fillings  are  needed, 
to  select  these  proximal  cases  at  the  first  sitting  and  pack  gutta-percha 
in  each  of  them.  He  may  then  proceed  with  other  work,  and  by  the 
time  that  is  completed  some  of  the  teeth  thus  wedged  will  be  found 
ready  to  operate  upon.  The  more  stubborn  cases  may  be  left  till 
the  last,  and,  if  necessary,  the  gutta-percha  may  be  renewed  in  these 
as  the  other  operations  are  in  progress." 

In  speaking  of  this  material  it  should  be  understood  that  the 
writer  has  in  mind  not  merely  that  known  as  "sheet"  or  "base-plate," 
but  the  various  kinds  of  prepared  gutta-percha  sold  by  the  dealers 
in  convenient  form  for  use.  They  are  easily  worked  but  inferior  to 
the  old-fashioned  sort  in  resistance  to  wear,  and  not  so  elastic.  The 
gray  gutta-percha  is  preferable  to  the  pink  only  for  its  appearance 
in  conspicuous  places. 

COTTON. 

Among  the  first  of  materials  used  for  separating  teeth  was  cotton, 
in  the  form  of  compressed  pellets,  pressure  depending  on  the  absorp- 


140  SEPARATION    OF    TEETH. 

tion  of  moisture;  and  it  is  still  used  by  some  almost  exclusively.  As 
a  separator  merely  it  is  more  effective  than  gutta-percha,  and  may  be 
preferred  whenever  a  considerable  space  is  demanded  within  a  limited 
time.  As  a  rule  it  produces  no  great  soreness,  and  if  the  teeth  are 
held  steady  by  the  mechanical  separator  during  the  subsequent  opera- 
tion, ordinary,  careful  malleting  is  well  borne  by  the  patient. 

But  the  cotton  pellet  is,  of  course,  unfit  for  a  temporary  stopping 
and  should  not  be  used  for  more  than  a  day  without  change.  If 
saturated  first  with  sandarac  varnish  as  it  sometimes  is,  making  it 
quite  impervious  to  moisture,  it  is  no  better  than  gutta-percha  for 
separating,  and  by  no  means  so  good  a  filling. 

Cotton  is  particularly  valuable  for  making  space  between  the 
incisors,  or  between  a  cuspid  and  a  lateral  incisor.  As  a  rule  the  pellet 
should  be  introduced  from  the  lingual  direction,  and,  with  a  thin- 
bladed  instrument  pressed  toward  the  incisal  borders  of  the  teeth. 
It  is  readily  seen  that  by  crowding  the  material  from  the  base  toward 
the  apex  of  the  interproximal  triangle  we  secure  the  advantage  of  two 
inclined  planes  along  the  teeth.  Now,  if  first  a  piece  of  waxed  thread 
shall  have  been  introduced  rootward,  it  may  be  drawn  down  upon 
the  pellet,  the  ends  carried  through  incisally  and  tied  firmly  so  as  to 
give  additional  compact  to  the  material.  Also  the  ligature  prevents 
crowding  out  of  the  cotton  toward  the  tongue  or  the  lip,  and  the  whole 
force  of  expansion  will  be  directed  against  the  teeth.  As  a  form  of 
cotton  for  this  and  many  other  purposes  the  writer  is  partial  to  "lin- 
tine"  or  "cottonoid,"  as  bought  in  sheets. 

RUBBER. 

An  easy  method  of  separating — easy  for  the  operator — is  that  of 
stretching  and  drawing  between  the  teeth  a  piece  of  rubber,  that  may 
be  cut  from  a  good  sized  elastic  band,  or  from  strips  of  different  thick- 
nesses and  widths  supplied  by  the  dealers.  But  these  if  kept  long 
on  hand  deteriorate  in  quality  and  become  worthless.  In  a  small 
proportion  of  cases,  with  phlegmatic  patients,  where  teeth  have 
short  crowns  with  long  roots  and  are  very  hard  to  move,  one  may  be 
justified  in  using  a  piece  of  rubber,  narrow  and  not  too  thick — to 
get  a  "start"  for  the  space  required.  Then,  if  the  mechanical  separa- 
tor is  insufficient,  some  other  material  should  be  used  to  induce  further 
separation  gradually. 

Nearly  always,  if  the  elastic  quality  of  rubber  is  depended  on 
entirely  for  a  considerable  movement  of  the  teeth,  much  annoyance 
or  real  suffering  will  be  experienced  by  the  patient,  not  only  through 


WOOD.  141 

the  period  of  wedging,  but  during  the  operations  to  follow.  While 
not  easy  to  account  for,  it  is  a  fact  of  experience,  that  the  pressure 
of  elastic  rubber  between  the  teeth  gets  "on  the  nerves"  of  a  great 
many  people  as  nothing  else  will.  One  risk  of  using  the  rubber  is 
that  of  injury  to  the  gum  tissue.  As  the  material  contracts  labio- 
lingually  it  bulges  into  the  interproximal  space  toward  the  gum,  and 
indeed  is  likely  to  slip  upon  the  surfaces  of  the  teeth  in  that  direction. 

WOOD. 

The  wooden  wedge  for  separating  teeth  has  been  much  employed. 
Of  the  many  woods  recommended  at  various  times  all  have  been 
quite  discarded  except  the  orange  wood,  which  is  supplied  in  neat 
bundles  by  the  supply  houses.  Where  one  suspects  the  presence  of 
a  small  proximal  cavity  in  a  very  close  space,  in  the  mouth  of  a  sensitive 
person,  where  the  insertion  of  cotton  or  gutta-percha  would  be  difl&cult 
or  ineffective  and  rubber  inadmissible,  where  allowable  force  with 
the  mechanical  separator  moves  the  teeth  but  slightly  and  an  increase 
of  space  must  be  had  by  the  slower  process,  then,  in  the  slight  space 
gained  by  screw  force,  we  may  insert  a  thin  wedge  of  wood,  by  hand 
pressure  merely  or  with  one  or  two  light  taps  of  the  mallet.  The 
wedge  may  then  be  separated  from  the  stick  with  cutting  pliers  made 
for  the  purpose.  If,  however,  before  its  insertion  a  sharp  notch  is 
cut  well  around  at  the  base  of  the  wedge,  it  will  afterward  break  off 
readily  from  the  body  of  the  stick,  and,  as  a  rule,  with  less  jar  than 
that  from  the  pliers. 

On  removal  of  the  separator  the  wedge  is  left  snug  in  place,  where 
by  slow  swelling  under  moisture  it  separates  the  teeth. 

TAPE. 

Some  practitioners  have  been  partial  to  waxed  linen  tape  of  various 
widths,  for  slow  separation.  The  unrolled  tape  is  dropped  into  hot 
beeswax,  let  cool,  and  is  then  stripped  of  adherent  wax.  With  slow, 
persistent  pressure,  this  thin  tape  may  be  crowded  between  the  teeth, 
and  usually  without  the  aid  of  a  mechanical  separator.  Otherwise, 
in  place  of  the  screw  separator  one  may  use  a  thin,  narrow  steel  wedge, 
at  the  end  of  a  strong  handle,  that  the  operator  may  if  he  chooses 
make  for  himself.  This  can  be  inserted  near  the  necks  of  the  teeth, 
and  by  hand  pressure  alone  will  induce  sufficient  space  between  the 
crowns  for  the  insertion  of  tape  or  thin  wood.  The  ends  of  the  tape 
may  be  cut  close  with  a  very  sharp  knife  or  fine  pointed  scissors. 
The  best  scissors  that  I  have  found  for  this  purpose,  and  that  I  keep 


142  SEPARATION    OF    TEETH. 

on  the  bracket  for  general  use,  is  a  small  "manicure"  pair  with  the 
extreme  sharp  point  of  each  blade  ground  away. 

Another  method  of  preparing  the  tape  is  to  dip  it  in  a  thin  solution 
of  gutta-percha  in  chloroform,  and  then  let  the  chloroform  evaporate. 
This  leaves  the  tape  permeated  with  a  film  of  gutta-percha,  which 
makes  it  very  tough  and  impervious.  It  will  therefore  not  deteriorate 
in  the  fluids  of  the  mouth  as  rapidly  as  waxed  tape. 

It  is  well  to  remember  that  wherever  slow  wedging  is  necessary, 
the  chief  difficulty  is  overcome  when  the  first  slight  space  has  been 
secured  for  a  day. 

THE  MECHANICAL  SEPARATOR. 

It  is  axiomatic  in  the  mechanical  world  that,  wherever  a  certain 
thing  is  to  be  done  in  a  particular  way,  a  specific  machine  accurately 
made,  and  intelligently  directed,  will  secure  results  more  uniform 
and  definite  than  are  possible  by  the  varying,  individual  hand  method. 

Operative  dentistry  consists  largely  of  a  series  of  mechanical 
problems,  and,  wherever  conditions  admit,  the  principle  above  stated 
holds  good.  To  a  celebrated  business  man  has  been  accredited  the 
statement  that  he  never  would  do  any  sort  of  work  himself  that  he 
could  hire  done  as  well  or  better  by  some  one  else.  We  may  say  in 
like  manner  of  any  mechanical  operator  that  as  a  rule  he  cannot 
afford  to  do  by  direct  effort  that  which  may  be  better  done  by  an 
intermediate  mechanical  contrivance.  As  a  recent  example  of  this 
principle  we  have  the  anatomical  articulator,  which  eliminates  much 
of  experiment  and  guess  work  in  the  proper  arrangement  of  artificial 
teeth. 

The  separation  of  teeth  as  considered  within  the  scope  of  this 
chapter  is  a  mechanical  process,  and  we  wish  to  know  how  far  it  may 
be  accomplished  by  the  application  of  screw  and  wedge  forces,  in  a 
manner  positive  and  definite.  What  are  the  requirements  of  such  an 
appliance,  and  have  they  been  successfully  met? 

First:  The  points  of  pressure  must  be  aside  and  far  away  from 
the  median  line  of  the  proximal  surface;  otherwise  they  will  intrude 
upon  the  field  of  operation,  or,  if  carried  too  far  rootward  will  press 
dangerously  on  the  interproximal  gum  tissue. 

Second:  The  pressure  having  to  be  well  aside  from  the  median 
line,  it  should  be  upon  both  sides  equally. 

Third:  As  the  separating  applies  to  both  teeth,  there  should  be 
necessarily  four  distinct  points  of  pressure  at  regular  distances. 

Fourth:    The  points  must  be  far  enough  over  the  crown  so  that 


THE    MECHANICAL    SEPARATOR. 


143 


1; 


Fig.  106. — Perry  Separators. 


144  SEPARATION    OF    TEETH. 

their  tenaency  under  pressure  will  be  to  move  rootward,  otherwise 
they  would  be  likely  to  slip  off;  but  they  must  at  the  same  time  be 
stayed,  to  prevent  their  going  too  far,  with  impingement  on,  and  danger 
of  injury  to,  the  soft  tissues. 

Fifth:  The  four  points  make  necessary  two  bars,  each  with  a 
right  and  left  hand  screw,  through  which  forces  may  be  exerted  alike 
in  both  directions. 

Sixth:  While  the  principle  of  the  instrument  is  everywhere  the 
same,  proportions  of  the  parts  must  vary  for  purposes  of  adaptation 
to  the  different  forms  and  classes  of  teeth,  considered  in  relation  with 
their  interproximal  spaces.  This  fact  precludes  the  construction 
of  any  so-called  "universal"  separator  which  shall  be  equal  to  the 
different  forms,  each  in  its  special  field.  Either  the  "universal" 
will  fail  to  meet  all  these  requirements — for  example,  having  points 
on  one  side  only  with  an  opposing  wedge;  or,  it  will  be  intricate  and 
cumbersome,  lacking  the  simplicity  of  the  special  instrument. 

Just  as  possible  a  universal  saw  for  the  carpenter,  or  a  universal 
pattern  for  a  coat,  as  of  one  separator  adapted  to  all  parts  of  the 
mouth.  It  is  altogether  probable  that  the  one  who  owns  a  "  set '  of  sepa- 
rators will  employ  one  form  or  another  much  oftener,  and  with  greater 
satisfaction  in  every  case,  than  the  possessor  of  a  "universal"  only. 
"The  best  is  none  too  good,"  as  relates  to  the  instruments  of  operative 
dentistry.  When  one  is  selecting  an  appliance  that  ought  to  last 
throughout  his  professional  life,  he  can  ill  afford  to  ignore  this  truth. 
It  is  here  that  the  mistake  of  a  moment  is  oft  the  detriment  of  years. 

THE  BEST  SEPARATOR. 

The  author  has  no  hesitation  in  saying  that  the  principles  of 
mechanical  separation  have  found  their  best  expression  in  the  "set" 
invented  by  Dr.  S.  G.  Perry,  originally  four  in  number,  now  six. 
These  various  forms  are  marvels  of  ingenuity,  adaptation  and  sim- 
plicity. Artistic  of  construction  yet  strong,  there  is  slight  chance  of 
their  being  superseded. 

The  usual  objection  offered  to  the  Perry  set  is  that  it  is  expensive; 
but,  if  we  take  into  consideration  both  usefulness  and  durability,  in 
the  long  run  it  will  prove  the  best  investment.  Few  dentists  would 
think  of  going  into  practice  without  a  good  chair  or  first  class  engine; 
and  yet,  one  might  perform  good  operations  over  a  plain  arm  chair 
with  a  head-rest.  The  writer  is  positive  that  he  would  rather  use  a 
cheap  chair  till  he  could  make  enough  money  to  buy  a  good  one,  than 
to  practice  one  month  without  the  Perry  separators. 


THE    BEST    SEPARATOR.  145 

Let  US  enumerate,  briefly,  some  of  the  advantages  and  uses  of 
mechanical  separation. 

First :    In  Examination  of  Teeth  for  Carious  Cavities. 

The  important  office  performed  by  the  separator  in  this  connection 
has  been  considered  in  Chapter  VII. 

Second:  Preparatory  to  Slower  Wedging  and  Temporary 
Stoppings. 

Where  it  is  evident  that  sufficient  space  cannot  be  had  with  the 
mechanical  separator  alone,  it  may  be  used  to  obtain  room  for  the 
insertion  of  cotton,  wood  or  gutta-percha;  and  in  like  manner  for  the 
introduction  of  gutta-percha  as  a  provisional  stopping. 

Third :    In  the  Preparation  of  Cavities  for  Filling. 

Time  and  observation  demonstrate  to  every  experienced  operator 
that  faulty  preparation  is  probably  the  commonest  fault  of  dentistry. 
Back  of  this  fault  very  often  lies  the  fact  of  insufficient  space— teeth 
that  have  had  no  separation;  or  having  been  separated  have  nothing 
to  keep  them  apart  for  operations  following: — For  what  sufficeth  it 
to  wedge  with  cotton  or  wood,  and  make  no  provision  for  holding  the 
space  obtained? 

The  mechanical  separator  will  do  this;  and  it  will  hold  the  teeth 
steady,  so  that  the  instrument  employed,  chisel,  excavator  or  bur, 
can  be  used  more  accurately,  and  with  less  pain  or  shock  to  the  patient. 
And  the  separator  with  four  points  generally  is  not  in  the  way  of 
observation,  does  not  obtrude  in  the  interproximal  space,  and  holds 
the  dam  aside  for  the  admission  of  light. 

It  is  well  to  remember,  however,  that  occasionally  where  wide 
lateral  extension  of  a  cavity  is  demanded,  either  for  "prevention" 
or  on  account  of  existing  decay,  a  point  of  the  separator  may 
impinge  upon  the  field  of  operation.  In  such  a  case  the  instru- 
ment may  be  used  for  preparation  of  the  main  cavity  and  then 
removed.  Before  removal,  however,  if  sufficient  space  exists  for 
the  insertion  of  a  narrow  wooden  wedge,  this  may  be  employed  to 
hold  the  space,  both  for  the  final  preparation  and  the  beginning  of 
the  filling. 

Fourth:    For  the  Insertion  of  Gold  Fillings. 

As  in  cavity  preparation,  the  separator  holds  the  teeth  steadily 
in  position  for  instrumental  service  in  filling.  It  makes  the  use  of  the 
plugger  more  accurate  and  positive,  and  the  application  of  mallet 
force  less  trying  to  the  patient. 

As  a  rule  where  a  tooth  is  filled  after  "immediate"  separation 
by  one  of  the  Perry  instruments,  with  or  without  slight  wedging  before- 


146  SEPARATION    OF    TEETH. 

hand,  the  patient  will  not  complain  of  any  malleting  necessary  for  the 
proper  condensation  of  gold. 

Fifth:    In  Connection  with  Porcelain  Inlays. 

The  mechanical  separator  may  assist  greatly  in  securing  access 
for  cavity  cutting  and  grinding,  facilitates  the  removal  of  a  matrix, 
or  the  insertion  of  an  inlay,  holds  the  teeth  apart  for  the  final  finish 
of  the  work,  especially  in  connection  with  the  anterior  teeth  and 
cavities  of  moderate  extension.  It  may  also  be  used  to  gain  space 
for  the  removal  of  inlays  that  have  become  loosened,  and  their  re- 
insertion. 

Sixth :    Preparatory  to  Filling  with  Amalgam  or  Cement. 

The  separator  gives  the  advantages  before  described  for  preparation 
and  initial  space.  The  teeth  are  held  apart  and  steady  up  to  the 
moment  of  applying  the  matrix,  or  with  the  use  of  a  hand  matrix  the 
separator  may  remain  in  position. 

Seventh :    For  the  Finishing  of  all  Proximal  Fillings.    . 

To  give  access  for  fine  cutting  instruments,  finishing  files,  tape  or 
disks,  for  proper  "knuckling,"  there  is  nothing  to  compare  with  the 
Perry  separators. 

In  Miscellaneous  Conditions  Requiring  Separation. 

Cases  are  presented  where  the  interproximal  space  has  been  left 
unprotected,  where  the  patient  is  distressed  by  food  impaction  with 
every  attempt  at  mastication  and  the  gums  perhaps  are  continually 
congested  and  sore,  in  consequence  of  previous  faulty  operations. 
Such  teeth  are  seldom  firm  in  their  sockets,  and  in  many  cases  may  be 
separated  by  the  "immediate"  method  sufiiciently  for  contour  restora- 
tions. Not  infrequently  we  find  some  foreign  substance,  a  piece  of 
wooden  tooth-pick  or  berry  seed  perhaps,  imbedded  between  the 
necks  of  teeth  and  hard  to  dislodge,  or,  as  occurred  recently  in  the 
writer's  practice,  one  may  discover  a  sequestrum  of  bone  as  the  result 
of  arsenical  poisoning.  In  such  cases  the  Perry  instrument  with  its 
widely  separable  points  will  render  valuable  aid. 

Final  Considerations. — To  adjust  the  mechanical  separator 
easily  and  deftly  requires  practice,  and  the  operator  must  not  expect 
smooth  sailing  in  every  case  at  first.  With  the  bicuspid  and  molar 
forms,  the  lip  of  the  patient  is  likely  to  be  lifted  up  uncomfortably. 
To  relieve  this  at  once  a  smooth  steel  instrument  like  the  handle  of  an 
explorer  should  be  inserted  at  the  angle  of  the  mouth  and  passed 
gently  forward,  lifting  the  lip  over. 

Whenever  the  separating  points  are  going  higher  than  they  should, 
so  as  to  crowd  upon  the  gums,  the  screws  should  be  relaxed  and  the 


THE   BEST    SEPARATOR.  1 47 

instrument  held  in  proper  position  while  gutta-percha  is  warmed  and 
crowded  under  the  bows.  When  this  is  hard  (and  cooling  may  be 
hastened  with  the  chip-blower),  the  rootward  movement  of  the  points 
is  prevented  and  separation  may  proceed.  The  screws  should  be 
kept  well  oiled,  both  for  ease  of  working  and  to  prevent  their  wearing 
out.  They  should  be  turned  on  beforehand  till  the  points  are  at  the 
distance  apart  that  will  just  allow  them  to  slip  over  the  teeth.  Then 
with  but  a  little  turning  the  instrument  finds  its  true  position,  and 
the  wrench  has  less  to  do  within  the  mouth. 

It  is  said  that  some  are  deterred  from  using  the  molar  separator 
by  what  they  consider  the  extreme  difficulty  of  its  application  in  con- 
nection with  the  rubber  dam,  for  in  most  cases  the  clamp  must  be 
dispensed  with.  It  is  not  hard  to  obviate  this  difficulty.  Apply 
the  dam  as  usual  and  the  clamp  temporarily.  Then  ligate,  if  nec- 
essary drawing  knots  of  thread  from  both  sides  into  the  furthest  inter- 
proximal space.  After  exchanging  the  clamp  for  the  separator  the 
rubber  will  rarely  become  displaced. 

The  writer  has  discovered  that  in  certain  unusual  cases  some 
forms  of  the  separators  may  be  used  in  a  manner  not  show^n  by  the 
^^  Directions. ^^  For  example,  one  may  find  molars  so  small  that  the 
bicuspid  form  would  apply — or  a  first  molar  so  much  larger  than  the 
second,  or  a  second  so  much  larger  than  the  third,  that  the  bicuspid- 
molar  separator  reversed — i.  e.,  with  the  larger  bow  forward,  will 
best  meet  the  requirement. 

Force  should  be  applied  always  with  immediate  reference  to  the 
feeling  of  the  patient — at  first  barely  to  the  point  where  he  admits 
that  the  pressure  is  uncomfortable — if  really  painful  the  screw  should 
be  turned  back  a  little.  One  may  say  to  the  patient  truthfully  that 
in  a  few  moments  the  feeling  of  undue  pressure  will  pass  off.  After- 
ward as  a  rule  there  will  be  no  objection  on  his  part  to  quarter  or 
half  turns  of  the  screws  with  intervals  of  rest  between.  Tact  and 
caution  on  the  part  of  the  operator  must  never  relax.  The  temptation 
to  hurry  and  crowd  must  be  resisted. 

Here,  as  in  relation  with  other  operative  procedures,  patients 
have  their  idiosyncrasies.  One  will  disclaim  any  sense  of  discom- 
fort whatever,  one  will  anticipate  trouble  that  does  not  come,  while 
another  is  truly  hyper-sensitive  and  deserving  of  the  most  delicate 
consideration.  Now  and  then,  once  a  year  possibly,  a  patient  will 
present  with  whom  the  separator  is  impracticable  by  reason  of  unusual 
tenderness  of  the  peridental  tissues  or  general  nervous  timidity. 

Much  depends  on  the  attitude  of  the  operator  in  the  first  intro- 


148  SEPARATION    OF    TEETH. 

duction  of  any  appliance  that  might  excite  the  fears  of  his  patient. 
If  we  show  to  the  patient,  older  or  younger,  the  necessity  of  space 
and  the  advantages  of  separation;  if  we  assure  him  that  we  shall  be 
careful  not  to  carry  the  pressure  beyond  the  point  of  reasonable  en- 
durance on  his  part;  if  we  are  painstaking  further  to  consult  with  him 
or  her  as  to  the  degree  of  force  that  may  be  easily  borne,  we  shall  have 
little  trouble  in  the  use  of  this  most  valuable  assistant. 


CHAPTER  IX. 

EXCLUSION  OF  MOISTURE  FROM  THE  TEETH 
DURING  OPERATIONS. 

BY    GEORGE    EDWIN    HUNT,    M.  D.,  D.  D.  S. 
GENERAL  CONSIDERATIONS. 

The  desirability  of  excluding  the  saliva  from  tooth  cavities  about  to 
be  the  scene  of  operative  procedures  is  based  on  four  considerations. 
First,  perfect  dryness  is  essential  to  secure  cohesion  of  gold.  Second, 
the  saliva  is  laden  with  micro-organisms,  many  of  which  in  their  life 
processes  form  by-products  detrimental  to  tooth  structure,  and,  there- 
fore, exclusion  of  the  saliva  is  necessary  that  the  tooth  structure  may  he 
sterilized.  Third,  saliva  obscures  and  distorts  the  view  of  the  walls 
and  angles  and  dryness  is  desirable  that  a  perfect  view  of  the  cavity 
may  be  obtained.  Fourth,  the  dentin  of  teeth  with  living  pulps  is  much 
more  sensitive  when  wet  and  dryness  is  necessary  to  diminish  the  pain 
of  excavating. 

Before  Dr.  Sanford  C.  Barnum,  of  New  York  City,  invented  the 
rubber  dam  and  gave  it  to  the  profession  in  1864,  dryness  of  tooth 
structure  was  obtained  by  the  use  of  napkins,  cotton  and  other  absorb- 
ents. The  exclusion  of  saliva  by  such  means  was  necessarily  of  com- 
paratively short  duration  and  extensive  operations  with  cohesive  gold 
were  impossible,  although  the  more  skillful  practitioners  in  those  days 
acquired  a  degree  of  dexterity  in  handling  napkins  and  absorbents  that 
is  seldom  seen  among  our  contemporaries.  Since  1864  nothing  has 
been  found  to  equal  rubber  dam  for  excluding  the  saliva  during  lengthy 
or  intricate  operations,  although  absorbents  may  be  used  in  many- 
short  operations  with  perfect  success  if  they  are  used  intelligently. 
It  is  therefore  necessary  that  the  operator  become  skilled  in  the  ad- 
justment of  the  rubber  dam,  to  the  end  that  it  may  be  used  to  the  best 
advantage  and  with  a  minimum  amount  of  annoyance  and  discomfort 
to  the  patient,  to  whom,  under  the  most  favorable  circumstances,  it  is 
a  trial.  Many  operators  do  not  use  the  rubber  dam  as  often  as  they 
should.  This  is  usually  due  to  the  fact  that  the  operator  is  unskill- 
ful in  adjusting  it  and  dreads  the  time  and  trouble  his  unskillfulness 
requires  to  place  it  in  position.  In  this,  as  in  all  other  manual  opera- 
tions, practice  alone  will  bring  ease  of  manipulation. 

149 


150   EXCLUSION    OF    MOISTURE    FROM    TEETH    DURING    OPERATIONS. 

THE  USE  OF  RUBBER  DAM. 

Rubber  dam  is  classified  as  heavy,  medium  and  light  in  weight, 
according  to  its  thickness.  Heavy  and  light  dams  each  have  their 
advantages  and  disadvantages.  Heavy  dams  are  less  likely  to  be  torn 
in  adjustment,  they  will  more  often  remain  in  place  without  the  use 
of  ligatures  or  clamps,  and  they  are  not  easily  caught  up  by  revolving 
burs,  stones,  discs  or  other  engine  instruments.  Light-weight  dams  are 
more  apt  to  be  torn  in  adjusting,  usually  require  ligatures  or  clamps 
to  hold  them  in  place,  and  are  readily  caught  up  by  engine  instruments 
by  which  they  may  be  torn  or  cut.  However,  owing  to  the  conforma- 
tion of  the  teeth,  or  their  relation  to  each  other,  it  is  often  difficult  to 
adjust  a  heavy  dam  where  a  light  one  can  be  carried  to  place  with  com- 
parative ease.  Therefore,  if  but  one  weight  of  dam  is  to  be  used,  a 
medium  weight,  which  diminishes  the  disadvantages  of  the  two  ex- 
tremes, is  best.  A  light  colored  dam  is  preferable  as  absorbing  less  and 
reflecting  more,  light.  Rubber  dam,  like  all  rubber,  deteriorates  with 
age  and  is  sometimes  ruined  by  the  manufacturer  in  vulcanizing.  A 
simple  test  for  quality  is  to  stretch  it  well  with  a  thumb  or  finger  and 
note  whether  it  returns  to  its  original  shape  without  bagging  or  tearing. 

Size  and  Shape. — For  operations  on  the  anterior  six  teeth  a  trian- 
gular shaped  piece  of  dam  will  be  found  both  efficient  and  economical. 
This  may  be  obtained  by  cutting  diagonally  a  piece  from  six  to  nine 
inches  square,  the  long  side  to  be  against  the  upper  lip  when  adjusted. 
For  the  posterior  teeth  a  piece  from  seven  to  nine  inches  square  will 
be  found  most  useful.  It  is  poor  economy  to  use  smaller  pieces  as  the 
edges  will  be  found  to  be  in  the  way  and  imperfect  exclusion  of  saliva 
from  the  exposed  surface  of  the  dam  may  result. 

The  Holes. — Holes  permitting  the  passage  of  the  tooth  crowns 
may  be  made  in  different  ways.  Various  sized  single  punches  may  be 
obtained  from  hardware  or  dental  supply  dealers  or  a  triangular 
punch,  capable  of  making  three  different  sizes  of  holes,  may  be  used. 
With  these,  the  dam  is  placed  on  a  block  of  wood  and  a  hammer  or 
mallet  used  on  the  punch.  Very  few  operators  now  employ  this 
method,  however.  The  most  efficient  method  is  by  the  use  of  one  of 
the  improved  rubber  dam  punches  on  the  market,  having  a  revolving 
steel  disk  with  four  or  more  round  holes,  varying  from  f  of  a  milli- 
meter to  *3  millimeters  in  diameter,  which  engage  a  pivoted  cone- 
shaped  steel  plunger,  punching  the  desired  sized  hole  in  the  dam. 

If  a  punch  is  not  available,  the  rubber  may  be  tightly  stretched  over 
the  tapering  round  handle  of  a  gold  plugger,  when  the  application  of 
a  sharp  knife  blade  to  the  tense  rubber  on  the  side  of  the  handle  will 


THE    USE    OF    RUBBER    DAM. 


151 


result  in  a  clean  cut,  round  hole.  The  size  of  the  hole  may  be  varied 
by  nicking  the  rubber  at  a  greater  or  less  distance  from  the  plugger 
end  and  a  little  experience  will 
enable  the  operator  to  thus 
cut  holes  of  any  desired  size. 
As  a  rule  operators  are  more 
apt  to  use  holes  too  small 
rather  than  too  large. 

The  distance   between  the 
holes    will   vary   in   different 
cases,  from  2  to  4  millimeters 
being    the   usual  distance  in 
medium  weight  rubber.     The 
lighter  the  rubber  the  further 
apart    the    holes    should  be. 
In  abnormal  cases,  where  the 
teeth  are  separated  or  the  gum 
tissue  has  receded,  the  holes 
may  have  to  be  much  further 
apart.    In  normal  cases,  teeth 
with   long   crowns   and    pre- 
senting   large    interproximal 
spaces,  require  that  the  strait 
of  rubber  between  the  holes  be 
wider  than  in  cases  where  the 
crowns  are  short  and  the  inter- 
proximal space  small.    These 
matters  should  be  noted,  for 
if  the  distance  between   the 
holes  is  greater  than  necessary, 
the  rubber  will  bag  in  the  inter- 
proximal space  and  be  in  the 
way,  and  if  it  is  less  than  it 
should  be  the  strait  of  rubber 
will  slide  down  between  the 
interproximal  gum  tissue  and 
the  proximal  surface  of  one  of 
the  two  teeth,   exposing  the 
gum  tissue  and  causing  a  leak. 
This  latter  will  also  occur  if  the  holes  punched  are  too  small,  requiring 
excessive  stretching  of  the  rubber  to  encircle  the  neck  of  the  tooth. 


Fig.  107. — Rubber  Dam  Punch. 


152    EXCLUSION    OF    MOISTURE    FROM    TEETH    DURING    OPERATIONS. 

The  location  0}  the  holes  will  be  governed  by  the  location  of  the 
tooth  to  be  operated  upon.  In  all  cases  the  holes  must  be  far  enough 
from  the  upper  edge  of  the  dam  to  permit  the  rubber  to  cover  the  upper 
lip  after  adjustment.  If  the  patient  has  a  moustache,  the  holes  must 
be  far  enough  from  the  upper  edge  of  the  rubber  for  the  latter  to  cover 
the  moustache.  But  in  no  case  should  the  rubber  cover  the  nostrils 
or  interfere  with  breathing  through  them.  For  teeth  on  the  right  or 
left  of  the  median  line  a  corresponding  variation  to  the  right  or  left  of 
the  median  line  of  the  dam  is  desirable  and,  in  a  general  way,  the  curve 
of  the  holes  should  correspond  to  the  curve  of  the  dental  arch.  The 
novice  should  hold  the  rubber  dam  against  the  teeth  to  be  isolated  and 
note  the  approximate  location  of  the  holes  necessary  to  have  the  dam 
cover  both  lips  properly  after  adjustment. 

The  number  of  teeth  isolated  by  the  dam  is  a  matter  of  importance. 
In  those  abnormal  cases  where  the  rubber  is  adjusted  with  great 
difficulty,  owing  to  the  shape  of  the  teeth,  wear  on  the  occlusal  sur- 
faces, unusual  resistive  power  of  the  facial  muscles  or  other  cause,  and 
in  treatment  cases  where  the  operation  is  short  and  easy  of  execution, 
the  number  of  teeth  isolated  may  be  much  reduced,  sometimes  even 
limited  to  the  one  tooth  to  be  operated  upon,  but  in  nearly  all  cases 
several  teeth  should  be  included.  This  is  desirable  in  that  it  gives 
better  light  and  better  access  by  getting  the  rubber  out  of  the  way 
and  diminishes  the  danger  of  catching  up  the  rubber  in  revolving  engine 
instruments.  The  opportunity  for  error  in  operative  procedures  is 
sufficiently  large  without  adding  to  it  inconveniences  within  the  control 
of  the  operator,  yet  many  operators  make  the  mistake  of  including  too 
few  teeth  when  adjusting  the  dam.  In  all  distal  surface  operations 
the  tooth  lying  distally  should  be  included.  In  operations  on  the 
anterior  teeth,  for  convenience  sake,  from  four  to  six  teeth  should  be 
isolated.  In  operations  on  the  molars  and  bicuspids  the  teeth  anterior 
should  also  be  isolated  up  to  and  including  either  the  lateral  or  central 
incisor.  On  account  of  its  anatomy  the  cuspid  is  an  unsafe  tooth  at 
which  to  stop.  It  has  less  of  a  constriction  at  the  neck  than  any  of  the 
other  teeth  and  the  dam,  whether  ligated  or  not,  is  more  likely  to  be 
worked  crownwards  by  the  action  of  the  tongue  and  lips  than  with 
other  teeth.  For  this  reason,  in  operations  on  the  lateral  incisors  the 
rubber  should  include  the  first  bicuspid  on  that  side  and  in  operations 
on  the  bicuspids  and  molars  should  extend  forward  to  one  of  the  incisors. 

Adjusting  the  Dam. — Prior  to  adjusting  the  dam,  if  the  cavity 
reaches  the  occlusal  surface  or  incisal  edge,  the  operator  should  care- 
fully note  the  articulation  and  the  landmarks  of  mastication  as  a  guide 


THE    USE    OF    RUBBER    DAM.  1 53 

for  the  fullness  of  his  filling.  If  the  teeth  set  very  closely  together  and 
especially  if  the  occlusal  surfaces  and  incisal  edges  are  badly  worn,  as 
in  an  "end  to  end"  bite  with  the  "ball  and  socket"  tempero- mandibu- 
lar articulation,  a  waxed  thread  should  be  passed  between  the  teeth 
about  to  be  isolated  and  all  calculus  and  rough  or  sharp  edges  of 
fillings  or  cavities  revealed  by  the  fraying  of  the  thread,  removed  and 
smoothed  so  the  dam  will  not  be  torn.  Dr.  C.  N.  Johnson  suggests 
that  a  thin  broad  instrument  like  a  gum  depressor  or  thin  spatula, 
forced  between  the  teeth  and  carried  rootwards  by  a  see-sawing  motion, 
will  smooth  rough  or  jagged  edges  of  enamel  left  by  caries  and  permit 
the  safe  passage  of  the  dam.  A  rubber  or  wooden  wedge  will  also 
move  the  teeth  in  a  few  moments  sufficiently  to  permit  the  passage  of 
the  rubber  at  any  particularly  difficult  point.  Just  before  proceeding 
to  adjust  the  rubber  the  tooth  crowns  should  be  swabbed  with  a  pledget 
of  cotton  dipped  in  absolute  alcohol,  to  remove  inspissated  mucus, 
food  debris  or  other  infectious  matter  which  might  be  crowded  under 
the  free  margin  of  the  gum  in  adjusting  the  dam. 

On  the  anterior  teeth  and  also  on  the  posterior  teeth  when  it  is  not 
intended  that  a  clamp  be  used,  the  dam  should  be  adjusted  first  over 
the  tooth  nearest  the  operator,  taking  the  others  in  succession.  By 
this  method  the  best  view  of  the  field  of  work  is  obtained.  The  dam 
should  be  stretched  labially  or  buccally  and  lingually  by  the  thumb 
and  fingers  of  the  right  and  left  hands  and  worked  rootwards  by  a  see- 
saw motion  until  the  rubber  is  well  down  to  the  cervix  and  the  strait 
between  the  holes  is  pressing  down  on  the  interproximal  gum  tissue. 
In  performing  this  operation  on  the  anterior  lower  teeth  the  operator 
stands  at  the  right  and  si  ghtly  in  front  of  the  patient,  the  fingers  of 
his  right  hand  guiding  the  rubber  on  the  labial  aspect  of  the  teeth,  his 
left  hand  fingers  within  the  oral  cavity  guiding  the  rubber  on  the  lingual 
aspect.  In  adjusting  the  dam  on  the  anterior  upper  teeth  the  position 
of  the  hands  is  reversed,  the  fingers  of  the  left  hand  caring  for  the  labial 
and  those  of  the  right  piloting  the  lingual  portions  of  the  rubber.  The 
position  of  the  hands  will  be  naturally  suggested  by  the  convenience 
of  the  operator  in  adjusting  the  dam  on  the  posterior  teeth,  the  right 
hand  guiding  the  buccal  and  the  left  the  lingual  portions  of  the  dam 
while  operating  on  the  left  side  of  the  mouth  and  the  positions  being 
reversed  on  the  right  side  of  the  mouth.  As  a  rule  simply  hanging 
the  rubber  on  the  teeth  as  described  is  all  that  is  necessary  at  this  time 
to  keep  it  in  position  but  if  there  is  a  decided  tendency  for  it  to  slip  oflf 
or  to  be  thrown  off  by  the  action  of  the  tongue  and  lips,  a  piece  of  waxed 
floss  silk  thread  should  be  passed  down  the  distal  surfaces  of  the  end 


154    EXCLUSION    OF    MOISTURE    FROM    TEETH    DURING    OPERATIONS. 

teeth  beyond  the  point  of  contact.  This  will  hold  the  rubber  in  place 
temporarily. 

In  difficult  cases,  where  the  teeth  are  closely  in  contact  and  have 
broad  contact  surfaces,  or  perhaps  facets  worn  on  the  proximal  sur- 
faces, a  little  vaseline  on  the  rubber  between  the  holes  will  facilitate 
its  passage  between  the  teeth.  Sometimes  the  use  of  a  waxed  silk 
thread  by  an  assistant  or  by  the  operator  is  necessary  to  carry  the  strait 
of  rubber  rootward  past  the  point  of  contact.  In  some  cases  the  pas- 
sage of  the  rubber  can  be  accomplished  by  stretching  it  well  and  tilting 
it  so  the  edge  of  the  rubber  strait  presents  at  the  point  of  contact  in- 
stead of  the  width.  If  the  rubber  is  securely  hung  over  the  first  tooth 
or  teeth  and  an  especially  difficult  point  is  reached,  it  may  be  passed, 
care  being  used  not  to  confuse  the  holes  and  tooth  crowns,  and  the  rubber 
adjusted  over  the  remainder  of  the  teeth,  the  operator  finally  returning 
to  the  refractory  one.  Occasionally  difficulty  will  be  experienced 
on  account  of  involuntary  movements  of  the  cheek,  lip  and  tongue  mus- 
cles. Dr.  C.  N.  Johnson  recommends  that  the  patient  be  given  a  hand 
mirror  with  which  to  view  the  operator's  efforts.  The  patient's  at- 
tention thus  being  directed  to  the  difficulty,  the  muscles  will  usually 
be  voluntarily  relaxed.  In  obstinate  cases,  if  this  method  does  not 
succeed,  the  application  of  the  dam  should  be  limited  to  as  few  teeth 
as  possible. 

Having  hung  the  rubber  on  the  teeth  temporarily  the  lower  edge  of 
the  dam  should  be  raised  and  a  napkin  placed  in  position  over  the  lower 
lip  so  the  dam  will  not  come  in  contact  with  the  lip  or  with  the  chin  or 
cheeks,  and  napkin  and  dam  secured  by  the  rubber  dam  holder.  A 
saliva-wet  dam  is  a  great  source  of  discomfort  and  annoyance  to  the 
patient  if  in  contact  with  the  skin.  The  patient  being  fairly  comfort- 
able and  the  lateral  edges  of  the  dam  held  back  out  of  the  way,  the 
operator  is  free  to  return  to  the  adjustment  of  the  rubber  to  the  teeth. 

To  insure  a  saliva-tight  joint  the  edge  of  the  rubber  must  be  turned 
rootward  so  it  will  pass  between  the  tooth  and  the  free  margin  of  the 
gum.  This  can  often  be  accomplished  by  simply  stretching  the  dam 
labially  and  lingually  and  working  it  well  rootwards  before  releasing  it. 
Sometimes  a  flat  instrument,  like  a  spatula,  run  around  the  cervix, 
will  turn  the  dam  margin  rootwards.  Ligating  the  tooth  will  always 
accomplish  this  result. 

Ligating  the  Teeth. — Ligatures  and  clamps  should  only  be  used 
when  they  are  necessary  to  the  success  of  the  operation,  but  they  are 
often  necessary.  If  the  carious  cavity  is  a  proximal  one,  the  tooth 
should  be  ligated  to  insure  security  of  the  dam.     For  the  same  reason  it 


THE    USE    OF    RUBBER    DAM.  1 55 

is  well  to  ligate  the  tooth  facing  the  cavity.  Often  the  end  teeth  of  those 
isolated  will  need  ligating  in  order  that  the  action  of  the  tongue,  cheeks, 
and  lips  may  not  force  the  rubber  crown-wise.  On  molars  and  bicus- 
pids, the  clamp,  as  will  be  explained  later,  takes  the  place  of  a  ligature 
on  the  tooth  to  which  it  is  applied.  In  operations  on  incisal  edges  or 
occlusal  surfaces,  or  in  treatment  cases  it  is  often  unnecessary  to  use 
ligatures  at  all. 

The  ligature  should  be  a  well  waxed  floss  silk  thread  made  for  the  pur- 
pose. If  the  interproximal  space  is  large  enough  to  permit  of  it,  the  liga- 
ture may  be  passed  from  labial  or  buccal  to  lingual  between  the  point  of 
contact  and  the  interproximal  gum  tissue  and  returned  in  the  same 
manner.  Usually  it  is  better  to  force  it  down  between  the  approxi- 
mating surfaces  past  the  point  of  contact.  Having  passed  it  rootward 
down  the  mesial  and  distal  surfaces  of  the  tooth  to  be  ligated,  the  ends 
should  be  gathered  up  and  the  portion  embracing  the  proximal  and 
lingual  surfaces  of  the  tooth  carried  rootward  by  traction,  the  rubber 
preceding  the  ligature.     This  will  curl  the  rubber  edge  rootwards,  as 


Fig.  108. — Surgeon's  Knot. 

desired.  Often  this  is  all  that  is  necessary  for  the  retention  of  the 
rubber  and  the  floss  silk  may  be  removed,  or,  in  cases  where  the  inter- 
proximal space  is  small  and  the  point  of  contact  well  rootwards,  the 
ends  of  the  thread  may  be  cut  off  close  to  the  labial  surface  of  the  tooth 
and  will  retain  the  rubber  in  position  by  its  wedging  action.  If  com- 
plete ligation  is  desirable,  the  first  part  of  a  surgeon's  knot  (see  Figure 
108)  should  be  tied  and,  just  before  it  is  drawn  taut,  traction  again 
made  rootward,  supplementing  this,  if  necessary,  by  carrying  the  thread 
rootward  with  a  suitably  shaped  blunt  instrument,  as  a  plugger,  used 
on  the  lingual  surface.  Having  carried  rubber  and  thread  fully  to 
the  cervical  constriction,  the  knot  should  be  tightened  and  the  tie  com- 
pleted. The  free  thread  ends  may  now  be  cut  off  close  to  the  knot 
with  curved  bladed  scissors  or,  if  an  end  tooth,  a  dam  weight  may  be 
fastened  to  the  ends  of  the  thread  and  the  weight  passed  back  and  left 
suspended  over  the  patient's  shoulder.     This  latter  method  assists  in 


156    EXCLUSION    OF    MOISTURE    FROM    TEETH    DURING    OPERATIONS, 

keeping  the  rubber  out  of  the  way  of  the  operator.  The  remaining 
teeth  should  now  be  ligated  in  rotation,  as  above  described. 

Dr.  E.  K.  Wedelstaedt  suggests  an  effective  method  of  ligating.  The 
first  portion  of  the  surgeon's  knot  is  made  on  the  lingual  surface  instead 
of  the  labial  or  buccal,  and  the  thread  ends  again  passed  through  the 
interproximal  spaces  to  the  labial  or  buccal.  Strong  traction  is  now 
made  on  the  thread  ends  and  the  half  completed  knot  on  the  lingual 
carried  rootwards  to  the  cervical  constriction,  with  a  suitably  shaped 
blunt  instrument.  A  full  surgeon's  knot  is  now  tied  on  the  labial  or 
buccal  surface,  completing  a  double  wrapped  ligature. 

Sometimes  the  action  of  the  muscles  or  the  shape  of  the  crown  causes 
the  rubber  to  slip  crown-wise  over  the  ligature.  This  is  most  apt  to 
occur  with  light-weight  dams  and  in  the  molar  region.  To  obviate  it, 
from  two  to  four  glass  beads  may  be  strung  on  the  ligature  and  ar- 
ranged at  effective  points  about  the  cervix  of  the  tooth.  Their  bulk 
will  prevent  the  rubber  slipping  over  them.  Dr.  Fernandez  suggests 
the  use  of  short  pieces  of  very  small  rubber  tubing  as  being  preferable 
to  the  beads.  Dr.  Wedelstaedt  suggests  tying  a  small  roll  of  cotton 
in  the  ligature,  to  secure  bulk.  Usually  a  bulky  knot,  which  may  be 
tied  in  the  thread  before  adjustment,  on  the  lingual  and  the  retaining 
knot  on  the  buccal,  will  be  sufficient. 

To  be  effective,  ligatures  must  encircle  the  tooth  at  the  cervical 
constriction.  Carrying  them  to  position  is  painful  in  some  cases  and 
painless  in  others,  owing  to  the  extent  the  gingival  gum  tissue  must  be 
forced  rootward  to  allow  the  adjustment  of  the  thread.  As  a  rule  the 
pain  felt  quickly  passes  away  as  the  tissue  recedes  before  the  pressure 
of  the  dam  and  thread,  but  if  it  is  severe  and  the  ligature  absolutely 
necessary,  the  rubber  should  be  everted  sufficiently  to  paint  the  gum- 
margin  with  a  two  per  cent  solution  of  cocaine  hydrochlorate.  The 
ligature  may  then  be  painlessly  adjusted  and  by  the  time  the  efifect 
of  the  anesthetic  has  worn  off,  the  gum  tissue  will  have  retracted  suffi- 
ciently that  pressure  is  relieved  and  further  pain  averted.  No  per- 
manent injury  to  the  gingival  margin  need  be  feared  unless  the  force 
used  in  adjusting  the  ligature  is  brutal  enough  to  tear  and  lacerate  the 
tissues,  and  with  ordinary  care  the  margin  will  return  to  its  original 
position  a  few  minutes  after  the  removal  of  the  rubber. 

In  some  cases,  where  there  has  been  considerable  recession  of  gum 
tissue  and,  perhaps,  of  alveolar  process,  and  correspondingly  large 
interproximal  spaces  present,  instead  of  using  ligatures,  w-ads  of  ab- 
sorbent cotton  may  be  packed  between  the  teeth,  holding  the  rubber 
to  place.     Whatever  method  is  employed,  the  operator  should  be  care- 


THE    USE    OF    RUBBER    DAM.  1 57 

ful  to  remove  all  retaining  material  or  appliances  before  attempting 
to  remove  the  dam. 

Clamps. — Clamps  are  used  to  hold  the  rubber  on  the  tooth  and  to 
keep  it  out  of  the  way  of  the  operator.  If  properly  selected  and  adjusted 
they  are  harmless  and  not  particularly  uncomfortable  but  if  not  so 
selected  and  adjusted  they  may  be  detrimental  to  tooth-structure  and 
soft  tissues,  and  very  painful  to  the  patient.  If  the  clamp  is  too  small, 
the  beaks  may  bite  into  the  enamel;  if  it  is  too  large  or  does  not  fit  the 
tooth,  it  may  be  forced  rootward  and  impinge  seriously  on  the  soft 
tissues;  if  carelessly  adjusted  the  gingival  tissue  may  be  severely  pinched 
by  the  beaks.  The  beginner  should  try  each  clamp  on  the  tooth 
and  note  that  it  encircles  the  cervix  properly,  before  attempting  the 
adjustment  of  the  rubber.  A  clamp  which  fits  the  cervix,  even  when 
carefully  adjusted,  may  crowd  the  gum  tissue  rootwardstosome  extent 
but,  as  with  ligatures,  no  permanent  injury  will  result  and  the  tissue 
will  resume  its  original  position  on  removal  of  the  pressure.  Cocain 
may  be  used  to  deaden  the  pain  of  adjustment,  if  necessary. 

Two  forms  of  teeth  are  especially  difficult  to  clamp  successfully, 
those  excessively  bell-crowned,  on  which  the  clamp  tends  to  slide  root- 
ward  and  impinge  seriously  on  the  gum  tissue,  and  those  short  crowned 
teeth  seemingly  or  really  larger  at  the  cervix  than  at  any  point  crown- 
ward,  from  which  the  clamp  tends  to  slip  o£f  occlusally.  In  both  cases, 
a  perfect  fitting  clamp  will  go  far  to  remove  the  difficulty.  Clamps 
have  been  devised  for  the  bell-crowned  teeth,  with  bows  so  arranged 
as  to  rest  on  the  occlusal  surface  and  prevent  the  slipping  of  the  beaks 
rootward;  and  it  has  also  been  recommended  that  gutta-percha  or 
other  plastic  material  be  placed  between  the  clamp-bow  and  the  occlu- 
sal surface,  but  none  of  these  methods  are  efficient  and  a  better  plan 
is  to  dispense  with  the  clamp  and  use  a  ligature.  In  many  of  the  short 
crowned  teeth  it  will  be  found  that  a  cervical  constriction  exists  if  the 
beaks  only  reach  it  but  that  the  gum  tissue  overlaps  the  cervix  unduly. 
If  this  is  not  the  case  and  the  tooth-crown  actually  narrows  occlusally, 
reliance  must  be  placed  on  a  perfect  fitting  clamp  and  caution  during 
the  operation  that  the  clamp  be  not  dislodged.  In  selecting  the  clamp 
for  these  cases  preference  should  be  given  one  with  beaks  having  a 
decided  rootward  inclination,  as  is  the  casd  with  the  Ivory  number 
14.  With  such  a  form  the  beaks  pass  between  the  crown  and  the  over- 
lapping gum  tissue  until  they  reach  the  cervix,  with  a  minimum 
amount  of  impingement  on  the  soft  parts. 

There  are  many  sets  of  clamps  on  the  market,  all  with  some  merit 
and  each  with  their  advocates.     Ordinarily  the  operator  will  use  one 


158    EXCLUSION    OF    MOISTURE    FROM    TEETH    DURING    OPERATIONS. 


of  a  few  standard  clamps  but  a  large  assortment  of  special  forms 
should  be  available  to  fit  the  extraordinary  cases  which  occasionally 
present. 

Usually  the  only  tooth  on  which  a  clamp  is  placed  is  the  posterior 
one  of  those  isolated  and  in  adjusting  the  rubber  on  molars  and  bi- 
cuspids, when  a  clamp  is  to  be  used,  the  operator  should  begin  with 
the  tooth  furthest  back  and  work  forward.  Having  selected  the  clamp 
best  adapted  to  the  tooth,  the  rubber  should  be  adjusted  on  that  tooth 
and  the  clamp  placed  in  position  by  means  of  the  clamp  forceps.  The 
difficulty  experienced  in  practicing  this  method  is  that  in  proportion  as 
the  clamp  is  needed  for  the  retention  of  the  rubber,  it  is  difficult  to 

keep  the  rubber  on  the  tooth  long 
enough  to  adjust  the  clamp.  To  ob- 
viate this  some  operators  stretch  the 
rubber  over  the  bow  of  the  clamp,  ad- 
just the  forceps  to  the  bow,  gather  up 
the  rubber  with  the  left  hand  and 
place  the  clamp  in  position  on  the 
tooth.  The  rubber  is  then  stretched 
with  the  fingers  until  it  slips  under  the 
beaks  of  the  clamp  and  encircles  the 
neck  of  the  tooth.  The  objections  to 
this  method  are  that  the  rubber  ob- 
scures the  view  of  the  tooth  except  in 
a  few  favorable  instances  where  it 
may  be  held  out  of  the  way  with  the 
left  hand  sufficiently  to  permit  of  the 
crown  being  seen,  and  that  stretching 
the  rubber  over  the  beaks  often  forces  the  latter  down  unduly  on  the 
soft  tissues.  The  Ivory  clamp  was  devised  to  meet  these  objections. 
This  clamp  has  buccal  and  lingual  flanges  on  the  beaks,  so  arranged 
that  the  bow  of  the  clamp  may  be  passed  through  the  hole  in  the  rub- 
ber and  the  latter  hung  on  the  two  flanges.  The  clamp  with  the  rub- 
ber in  position  is  now  taken  up  by  forceps  designed  for  this  purpose 
and  adjusted  on  the  tooth,  the  rubber  being  so  stretched  over  the 
flanges  as  to  bring  the  t(?oth-crown  into  view  as  the  clamp  is  carried 
to  place.  The  rubber  is  then  slipped  rootward  from  the  flanges  and 
encircles  the  cervix.  Mesial  projections  on  the  beaks  keep  the  rubber 
from  obscuring  the  view  of  the  mesio-cervical  portion  of  mesial  cavi- 


FiG.  109. — Ivory  Clamps. 


ties. 


Cervical  Clamps. — Buccal,  labial  and  lingual  cavities,  with  all 


THE    USE    OF    RUBBER    DAM. 


159 


or  a  portion  of  the  cavity  lying  rootwards  from  the  cervical  line,  re- 
quire the  use  of  cervical  clamps  if  any  clamp  at  all  is  used.  The 
wide  range  of  location  met 
with  in  these  cavities  renders 
it  desirable  that  the  operator 
have  several  forms  of  clamps 
to  meet  the  differing  condi- 
tions, although  the  mechanical 
improvement  in  some  forms 
has  been  so  great  in  recent 
years  that  they  may  be  used 
successfully  in  widely  varying 
cases  by  change  of  adjustment. 
The  Ivory,  Keefe  and  Dunn 
are  all  useful  and  have  a  con- 
siderable range  of  adjustment. 
The  use  of  cervical  clamps 
is  often  attended  by  much 
pain,  due  to  forcing  the  soft 
tissues  rootward  sufficient  to 
allow  the  beak  a  bearing  on 
normal  cementum.  If  possi- 
ble, the  gum  tissue  should  be 
retracted  previous  to  the  opera- 
tion by  packing  the  cavity 
with  gutta-percha.  If  the 
cavity  is  not  of  a  retentive 
form  the  gutta-percha  may  be 
held  in  position  with  a  wire  or 
thread  ligature.  In  superficial 
caries  where  this  is  impossible, 
the  soft  tissues  may  be  divided 
by  a  longitudinal  cut  and  the 
flaps  pressed  out  of  the  way. 
On  completion  of  the  opera- 
tion the  incised  tissue  should 
be  pressed  into  apposition 
and  gently  massaged  with  the 

_  .  Fig    110. — Brewer  Clamp  Forceps, 

nnger  tip. 

I  Rather  than  adjust  a  cervical  clamp  many  operators  hold  the  dam 

to'place  with\  pointed  instrument  while  filling  the   subgingival  por- 


l6o    EXCLUSION    OF    MOISTURE    FROM    TEETH    DURING    OPERATIONS. 


tion  of  the  cavity  and  still  others  prefer  to  use  absorbents  in  a  manner 
to  be  described  later,  using  amalgam  for  the  subgingival  portion  in 
molars  and  bicuspids,  and  pellets  or  cylinders  of  non-cohesive  foil  in 
the  anterior  teeth,  afterward  adjusting  the  rubber  dam  and  finishing 
the  operation  with  the  filling  material  indicated  for  the  case  in  hand. 
In  all  cases  where  clamps  and  ligatures  are  used,  as  in  all  other 
steps  in  operations  in  the  oral  cavity,  the  comfort  of 
the  patient  should  be  considered,  and  while  the 
operator  would  grossly  err  in  allowing  his  regard 
for  the  feelings  of  his  patient  to  interfere  with  the 
perfect  performance  of  the  operation,  it  is  often 
possible  to  save  the  patient  annoyance  and  discom- 
nm,         fort  by  the  exercise  of  judgment  and  care. 

THE  SALIVA  EJECTOR,  BIBS,  ETC. 


Fig.  III. — Ivory 
Cervical  Clamp. 


In  some  cases  the  required  posture  of  the  patient 
or  the  location  of  the  adjusted  rubber  dam  interferes 
seriously  with  the  swallowing  of  the  saliva.  Opera- 
tions on  the  upper  molars,  where  the  chin  of  the  patient 

is  elevated  and  the  neck  muscles  tense,  are  examples  of  the  first  class, 

and  the  adjustment  of  the  rubber  on  the  lower  molars  illustrates  the 

second  class.     In  some  cases,  also,  the  mental  state  of  the  patient  or 

the  pain  of  excavation  will  result  in  an  abnormal  amount  of  saliva 

being  delivered  to  the  oral  cavity.     Whether  due  to  larger  amounts  of 

saliva  or  to  the  inability  of  the  patient  to  dispose  of  it  by  swallowing, 

the  excess  will  drool  from  the  mouth  and  should  be 

cared  for.     Rubber  bibs  for  the  protection  of  the 

patient's  clothing  may  be  used  or  towels  placed  over 

the  chest.     The  saliva  ejector  is  of  great  help  in  these 

cases,  by  siphoning  off  the  saliva.     Occasionally  a 

nervous  patient  will  be  found  who  objects  to  its  use 

but  many  others  will  stand  the  pain  of  excavating 

and  the  strain  of  a  long  operation  far  better  if  they 

are  instructed  in  the  use  of  the  ejector  and  allowed 

to  manipulate  it.     The  diversion  of  attention  from 

the  operation  to  the  manipulation  of  the  ejector  is, 

of  course,  responsible  for  this. 


Fig.  112. — Keefe 
Clamp. 


RUBBER  CUPS,  COTTON  ROLLS  AND  NAPKINS. 

As  has  been  previously  remarked,  before  the  days  of  rubber  dam, 
napkins  and  other  absorbents  were  the  only  available  means  for  the 


RUBBER    CUPS,    COTTON    ROLLS    AND    NAPKINS..  l6l 

exclusion  of  saliva.  In  later  years  some  efforts  have  been  made  to 
increase  the  efficiency  of  the  methods  employed  in  using  absorbents 
but,  in  the  opinion  of  the  writer,  they  have  been  futile.  By  the  old 
methods,  absorbents  skillfully  manipulated  will  exclude  saliva  in  nor- 
mal mouths  for  from  twenty  to  thirty  minutes,  or  longer,  without 
distressing  the  patient.  For  short  operations,  such  as  redressing  a 
pulp  canal  or  inserting  a  temporary  filling,  this  is  more  than  ample 
time.  The  writer  has  seen  large  occlusal  cavities  in  lower  molars 
filled  with  non-cohesive  cylinders  and  finished  with  cohesive  foil  while 
the  saliva  was  excluded  by  the  use  of  napkins.  The  subject  of  the 
exclusion  of  saliva  by  the  use  of  other  materials  than  the  rubber  dam 
may  be  divided  as  follows: — First,  the  use  of  rubber  cups;  second,  the 
absorption  of  the  saliva  after  it  flows  into  the  mouth;  third,  the 
prevention,  partially  or  totally,  of  the  delivery  of  saliva  to  the  oral 
cavity. 

*  Rubber  Cups. — Rubber  cups  known  as  Denham's  coffer  dam 
shields,  fashioned  like  the  cups  used  for  carrying  pumice  for  polishing 
teeth,  are  used  with  some  success  for  short  operations.  The  base  of 
the  cup  is  of  thin  rubber.  A  hole  is  made  in  the  base  with  the  rubber 
dam  punch  and  the  cup  adjusted  on  an  Ivory  or  similar  clamp.  The 
clamp  is  then  carried  to  place  on  the  tooth  and  the  rubber  slipped  over 
the  flanges  of  the  clamp  as  described  in  the  use  of  rubber  dam.  In 
pulp  canal  treatment  of  lower  teeth  where  the  adjustment  of  the  dam 
is  particularly  difficult,  these  cups  may  be  used  to  advantage.  The 
saliva  ejector  may  also  be  used  to  assist  in  reducing  the  amount  of 
saliva  in  the  mouth. 

The  Use  of  Absorbents. — Absorbing  the  saliva  after  it  flows 
into  the  mouth  may  be  accomplished  by  napkins  or  by  specially  pre- 
pared rolls  of  absorbent  cotton.  The  manner  in  which  this  is  done 
will  readily  suggest  itself  to  the  operator.  The  roll  or  napkin  is  ad- 
justed in  a  V  shape  with  the  free  ends  to  the  anterior,  the  bottom  of 
the  V  just  posterior  to  the  tooth  to  be  operated  on  and  the  roll  resting 
against  the  buccal  and  lingual  surfaces  of  the  teeth.  Special  clamps, 
with  large  flanges,  designed  to  clasp  the  roll  or  napkin  and  hold  it 
firmly  against  the  gums,  may  be  had.  Where  this  method  of  excluding 
saliva  is  efficient,  the  clamps  are  an  advantage  in  that  they  permit 
the  operator  to  use  both  hands.  If  the  quantity  of  saliva  delivered 
to  the  mouth  is  small,  this  method,  in  connection  with  the  saliva 
ejector,  may  meet  with  success. 

The  Exclusion  of  Saliva  from  the  Mouth. — The  older  operators 
depended  far  more  on  the  exclusion  of  the  saliva  from  the  mouth  than 


1 62    EXCLUSION    OF    MOISTURE    FROM    TEETH    DURING    OPERATIONS. 

on  its  subsequent  absorption.  This  may  be  accomplished  by  stopping 
the  salivary  ducts  at  the  point  where  they  open  into  the  oral  cavity. 
For  this  purpose,  napkins  from  four  to  five  inches  wide  and  about 
twelve  inches  long,  are  desirable.  These  may  be  cut  from  a  piece  of 
clean,  bleached  linen  and  thrown  away  after  use'.  The  napkin  should 
be  folded  longitudinally  until  it  presents  a  width  of  an  inch  to  an  inch 
and  a  half.  For  operations  on  the  right  side  below,  the  patient  should 
be  instructed  to  raise  the  tip  of  the  tongue  to  the  roof  of  the  mouth  and 
the  napkin  adjusted  across  the  mouth  from  left  to  right,  the  end  resting 
against  the  lingual  surfaces  of  the  teeth  on  the  left  side.  The  tongue 
tip  is  then  lowered  and  the  free  end  of  the  napkin  carried  from  right  to 
left  over  the  dorsum  of  the  tongue.  Rolls  or  wads  of  absorbent  cotton 
are  then  adjusted  between  the  buccal  surfaces  of  the  upper  molars  and 
the  cheeks,  closing  the  openings  from  the  parotid  ducts.  The  fore- 
finger of  the  left  hand  resting  on  that  portion  of  the  napkin  covering 
the  dorsum  of  the  tongue,  is  used  to  hold  the  tongue  firmly  against  the 
floor  of  the  mouth  and  the  other  fingers  are  used  to  hold  the  right  cheek 
out  of  the  way,  the  thumb  being  pressed  firmly  against  the  under  part 
of  the  chin.  If  there  is  an  excessive  flow  of  saliva  from  the  right  parotid 
duct,  the  cotton  covering  it  may  be  removed,  when  saturated,  and  a  dry 
piece  quickly  and  easily  adjusted.  This  is,  however,  not  often  neces- 
sary. For  operations  on  the  left  side  below,  the  napkin  is  reversed, 
starting  with  the  end  resting  against  the  lingual  surfaces  of  the  right 
teeth,  passing  under  the  tongue  from  right  to  left  and  over  the  dorsum 
from  left  to  right.  The  forefinger  of  the  left  hand  is  now  used  to  hold 
the  left  cheek  away  from  the  buccal  surfaces  of  the  teeth,  while  the 
other  fingers  depress  the  tongue  and  the  thumb  insures  immobility 
by  its  position  under  the  chin. 

Occasionally  a  patient  will  be  found  whose  tongue  involuntarily 
resists  the  effort  to  depress  it  but  that  ceases  under  firm,  steady  treat- 
ment. The  napkin  over  the  dorsum  permits  the  operator  to  compel 
obedience  from  the  tongue  muscles  that  would  be  impossible  with  the 
bare  fingers  against  the  bare  mucous  membrane.  By  this  method 
the  secretion  from  the  submaxillary  and  sublingual  ducts  is  kept  out 
of  the  mouth  completely.  Care  must  be  exercised  in  removing  the 
napkin  for  the  mucous  membrane  dries  so  thoroughly  it  might  be  in- 
jured by  roughness  or  haste. 

The  difficulty  in  excluding  saliva  during  operations  on  the  upper 
teeth  is  much  less.  Here  we  only  have  the  parotid  duct  to  consider 
and  the  use  of  a  napkin  as  described  above  under  the  head  of  the  use 
of  absorbents,  is  usually  sufficient.     It  acts  not  only  as  an  absorbent 


RUBBER    CUPS,    COTTON    ROLLS    AND    NAPKINS.  163 

but  also  lessens  the  quantity  of  saliva  delivered  through  the  parotid 
duct.     In  some  cases  it  may  be  advisable  to  also  use  the  ejector. 

A  form  of  tongue  depressor  consisting  of  a  duckbill  arm  to  rest  on 
the  dorsum  of  the  tongue,  a  suitably  shaped  shield  to  rest  against  the 
under  side  of  the  chin,  and  a  ratchet  arrangement  whereby  the  depressor 
may  be  locked  when  the  relations  between  the  tongue  and  shield  are 
such  that  the  tongue  is  fully  depressed,  may  be  bought  of  dealers  in 
surgical  instruments  and  Dr.  Henry  A.  King,  of  New  York,  produced 
a  similar  device  on  lighter,  more  graceful  lines,  in  1904.  If  the  patient 
does  not  object  to  their  use,  these  instruments  permit  of  the  use  of  the 
napkin,  as  described,  with  both  hands  free. 


CHAPTER  X. 
PREPARATION  OF  CAVITIES  FOR  FILLINGS. 

BY    A.    E.    WEBSTER,    M.  D.,  L.  D.  S.,    D.  D.  S. 

Definition. — Under  this  heading  is  included  all  those  operations 
which  have  for  their  purpose  the  removal  of  carious  tooth  tissue, 
formation  of  cavities  for  the  reception  and  the  retention  of  fillings  and 
the  extension  of  cavity  walls  to  prevent  further  decay. 

Nomenclature. — In  every  nation  or  class  of  people  living  and 
associating  together  is  developed  a  system  of  signs  or  sounds  by  which 
ideas  are  communicated  to  each  other.  This  is  their  language.  In 
every  business  or  trade  or  occupation  there  is  similarly  developed  a 
system  of  signs,  words  and  names  which  are  used  by  those  engaged  in 
the  same  trade  or  occupation  as  a  means  of  communication.  These 
signs  and  names  are  termed  the  nomenclature  of  the  trade  or  profession. 
Without  such  a  code  those  in  the  same  occupation  would  not  be  able  to 
understand  each  other.  So  in  the  subject  of  the  preparation  of  cavi- 
ties it  is  necessary  to  have  a  system  of  names  and  signs  which  all  must 
understand  before  communication  is  possible.  The  majority  of  the 
names  used  in  the  preparation  of  cavities  will  be  familiar  to  those  who 
have  studied  dental  anatomy.  Others  will  be  defined.  The  nomen- 
clature followed  will  be  that  adopted  by  the  Institute  of  Dental  Peda- 
gogics. 

Cavity  Nomenclature. — Cavities  in  teeth  take  the  names  of  the 
surfaces  of  the  teeth  in  which  they  occur. 

Labial  cavities  occur  in  labial  surfaces. 

Buccal  cavities  occur  in  buccal  surfaces. 

Lingual  cavities  occur  in  lingual  surfaces. 

Occlusal  cavities  occur  in  occlusal  surfaces. 

Mesial  cavities  occur  in  the  surfaces  of  the  teeth  looking  toward 
the  median  line. 

Distal  cavities  occur  in  the  surfaces  of  the  teeth  looking  away 
from  the  median  line. 

Proximal  cavities  are  those  which  occur  in  the  proximal  surfaces 
of  the  teeth. 

Cavities  which  involve  more  than  one  surface  take  the  name  of  the 
two  or  more  surfaces  involved,  thus: 

165 


l66  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

Mesio-occlusal  cavities  involve  both  the  mesial  and  the  occlusal 
surfaces. 

Disto-occlusal  cavities  involve  both  the  distal  and  the  occlusal 
surfaces. 

Mesio-labial^  cavities  involve  both  the  mesial  and  the  labial 
surfaces. 

Mesio-lingual  cavities  involve  both  the  mesial  and  the  lingual 
surfaces. 

Disto-lingual  cavities  involve  both  the  distal  and  the  lingual 
surfaces. 

Mesio-occluso-distal  cavities  involve  the  mesial,  occlusal  and 
the  distal  surfaces.  Other  combinations  may  be  made  to  describe 
the  location  of  cavities. 

CLASSIFICATION  OF  CAVITIES. 

Teeth  usually  begin  to  decay  in  defects  of  the  enamel  surface  or 
on  smooth  surfaces  not  kept  clean.  Thus  they  may  be  divided  into 
two  general  classes;  pit  and  fissure  cavities,  and  smooth  surface  cavi- 
ties. Pit  and  fissure  cavities  do  not  require  to  be  extended  beyond  the 
limits  of  decay  or  the  defect  in  the  enamel,  while  those  on  smooth  sur- 
faces usually  require  to  be  extended  sufficiently  to  bring  the  margin 
of  the  filling  to  a  point  on  the  tooth's  surface  where  it  is  kept  clean 
either  by  the  excursions  of  food  or  by  the  actions  of  the  lips  or 
tongue. 

Pit  and  fissure  cavities  occur  in  the  lingual  surfaces  of  upper  in- 
cisors and  occasionally  in  cuspids,  and  in  the  occlusal  surfaces  of 
bicuspids  and  molars  and  the  occlusal  and  middle  thirds  of  the  buccal 
and  the  lingual  surfaces  of  molars. 

The  classification  of  cavities  which  follows  requires  a  similar 
method  of  treatment  for  each  class. 

Pit  and  Fissure  Cavities. — Cavities  in  the  occlusal  and  middle 
thirds  of  buccal  and  lingual  surfaces  of  molars. 

Cavities  in  occlusal  surfaces  of  bicuspids  and  molars  and  lingual 
surfaces  of  upper  incisors  and  occasionally  upper  cuspids. 

Smooth  surface  cavities  occur  in  the  surfaces  not  kept  clean  and 
may  be  classified  as  to  location  as  follows: 

1.  Cavities  in  the  gingival  third  of  labial,  buccal,  and  lingual  sur- 
faces. 

2.  Cavities  in  proximal  surfaces  of  incisors  and  cuspids  which  do  not 
involve  the  incisal  angle. 


NOMENCLATURE    OF    THE    INTERNAL    PARTS    OF    CAVITEES.         167 

3..  Cavities  in  the  proximal  surfaces  of  incisors  and  cuspids  which  do 
involve  the  incisal  angle. 

4.  Cavities  in  proximal  surfaces  of  bicuspids  and  molars  which  do 
not  involve  the  occlusal  surface. 

5.  Cavities  in  the  proximal  surfaces  of  bicuspids  and  molars  which 
do  involve  the  occlusal  surface. 

NOMENCLATURE  OF  THE  INTERNAL  PARTS  OF  CAVITIES. 

The  surrounding  walls  of  a  cavity  take  the  names  of  those  surfaces 
of  the  teeth  toward  which  they  are  placed,  thus  an  occlusal  cavity  has  a 
mesial  wall,  a  buccal  wall,  a  distal  wall,  a  lingual  wall  and  a  fifth  wall 
which  is  known  as  the  pulpal  wall. 

The  pulpal  wall  of  a  cavity  is  that  wall  which  is  occlusal  to  the  pulp 
and  at  right  angles  to  the  long  axes  of  the  tooth.  If  the  pulp  be  re- 
moved the  floor  of  the  pulp  chamber  becomes  a  wall  of  the  cavity  and 
is  known  as  the  sub-pulpal  wall.  In  cavities  occurring  in  the  axial 
surface  that  wall  covering  the  pulp  is  called  the  axial  wall  and  if  the 
pulp  be  removed  the  wall  takes  the  name  of  the  w^all  of  the  pulp  cham- 
ber. Cavities  in  the  axial  surfaces  of  teeth  have  mesial  and  distal, 
or  buccal  and  lingual  walls,  and  an  occlusal  and  a  gingival  wall,  and  an 
axial  wall. 

In  complex  cavities  which  involve  the  axial  and  occlusal  surfaces 
the  gingival  wall  is  termed  the  seat  of  the  cavity  and  the  pulpal  w^all  is 
known  as  the  step. 

For  purposes  of  convenient  description  cavities  in  teeth  are  supposed 
to  be  cuboid  in  form. 

Where  two  walls  join,  a  line  angle  is  formed  taking  the  name  of  the 
two  walls  entering  into  its  formation,  thus:  Bucco-pulpal  line  angle 
or  gingivo-axial  line  angle. 

Where  three  walls  join,  a  point  angle  is  formed  taking  the  name  of 
the  walls  entering  into  its  formation,  thus:  Gingivo-labio-axial  point 
angle  or  gingivo-linguo-axial  point  angle. 

The  enamel  wall  of  a  cavity  is  that  portion  of  the  wall  between  the 
cavo-surface  angle  and  the  dento-enamel  junction  and  includes  the 
thickness  of  the  enamel. 

The  dentin  wall  is  that  portion  of  a  cavity  which  is  lined  with 
dentin. 

The  enamel  margin  includes  the  whole  outline  of  the  cavity  and  is 
equivalent  to  the  marginal  line  of  the  cavity. 

The  cavo-surface  angle  of  a  cavity  is  the  angle  formed  by  the  junc- 
tion of  the  wall  of  the  cavity  with  the  surface  of  the  tooth. 


l68  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

THE  PLANES  OF  THE  TEETH. 

The  horizontal  plane  is  at  right  angles  to  the  long  axis  of  the  tooth. 

Mesio-distal  plane  is  parallel  with  the  long  axis  and  passes 
through  the  tooth  from  mesial  to  distal. 

Bucco-lingual  plane  is  parallel  with  the  long  axis  and  passes 
through  the  tooth  from  buccal  to  lingual. 

The  bevel  of  the  cavo-surface  angle  is  reckoned  from  the  plane  of 
the  enamel  wall. 

DIVISIONS  OF  TEETH  AND  CAVITIES. 

For  convenience  of  locating  a  cavity  on  the  axial  wall  of  a  tooth 
the  tooth  may  be  divided  into  thirds,  and  known  as  the  occlusal  third, 
middle  third  and  the  gingival  third.  Cavities  in  teeth  may  be  divided 
in  the  same  way  either  in  the  horizontal  plane  or  in  the  mesio-distal 
plane,  thus:  A  buccal  cavity  is  located  in  the  gingival  third  in  the 
horizontal  plane,  and  in  the  middle  third  in  the  mesio-distal  plane. 

STEPS  IN  CAVITY  FORMATION. 

The  beginner  in  any  mechanical  work  does  not  at  once  arrive  at  the 
best  and  most  expeditious  methods  of  procedure.  But  after  a  time 
if  he  be  an  observing  person  he  will  fall  into  an  order  of  procedure 
which  he  will  follow  more  or  less  rigidly.  Hence  it  is  important  that 
he  should  at  first  at  least  follow  those  who  have  had  opportunities  of 
developing  the  best  methods.  The  Institute  of  Dental  Pedagogics 
has  given  the  following  steps  in  cavity  formation  as  those  fulfilling 
the  greatest  number  of  requirements. 

1.  Establish  the  outline  of  the  cavity  (outline  form). 

2.  Remove  the  softened  decay. 

3.  Give  the  cavity  proper  form.  Which  includes  convenience  form, 
resistance  form  and  retentive  form. 

4.  Bevel  and  polish  the  enamel  wall. 

5.  The  final  touches  or  the  toilet  of  the  cavity  should  include  a  care- 
ful observation  of  the  condition  of  the  tooth  tissue  over  the  pulp  and  a 
thorough  cleansing  of  the  cavity  surfaces. 

General  Consideration  of  Outline  Form. — Before  a  dentist  is 
justified  in  undertaking  the  treatment  of  a  patient's  teeth  for 
the  purpose  of  eradicating  present  caries  and  the  prevention  of  fu- 
ture decay  he  should  consider  well  all  the  factors  which  enter  into 
the  causation  of  decay  and  its  prevention.  The  family  history  and 
the  personal  history  of  caries  are  of  value  in  deciding  the  character 
of  the  operations  to  be  performed. 

Family  Traits. — ^In  some  families  even  though  there  be  many  cavi- 
ties while  young,  they  yield  to  treatment  and  fillings  have  a  degree  of 


STEPS    IN    CAVITY    FORMATION.  169 

permanency  not  found  in  others  of  more  favorable  appearance.  Then 
again  caries  in  some  famihes  rarely  appears  before  the  fifteenth  year 
while  in  others  it  begins  at  the  appearance  of  the  deciduous  teeth. 
Caries  will  cease  at  the  twentieth  year  in  some  families  and  not  recur 
until  perhaps  the  fiftieth  year  or  perhaps  not  at  all.  Patients  giving  a 
family  history  of  immunity  after  a  certain  age  and  a  personal  history  of 
immunity  at  the  same  age  need  not  have  what  are  sometimes  called 
heroic  operations  done  for  them.  The  greatest  attention  in  such  cases 
should  be  given  to  the  prevention  of  present  decay  rather  than  that 
which  may  occur  in  the  future.  Such  conditions  might  influence  to  a 
large  extent  the  location  of  the  cavity  margins. 

Physical,  Mental  and  Personal. — ^The  physical,  mental,  and  personal 
habits  have  a  great  influence  on  the  character  of  operations  that  should 
be  performed.  Many  patients  apply  for  dental  treatment  who  are  not 
in  a  fit  physical  condition  to  have  ideal  dental  operations  performed. 
A  dentist  would  be  lacking  in  judgment  who  would  ask  a  frail  girl  ma- 
turing into  womanhood  to  submit  to  having  the  outline  of  many  proxi- 
mal cavities  carried  through  sensitive  tissue  to  bring  them  to  a  clearing 
margin.  Then  again  there  are  those  who  are  so  weak  mentally  that  it 
takes  careful  management  to  preserve  their  teeth  at  all.  They  think 
they  cannot  bear  anything  in  the  way  of  inconvenience.  Such  patients 
need  the  strong  controlling  force  of  a  man  who  knows  just  how  to  handle 
them  before  he  may  venture  to  do  ideal  operations. 

Natural  Cleanliness. — Some  patient's  teeth  are  kept  perfectly  clean 
apparently  without  an  effort.  They  eat  proper  foods  and  masticate 
them  well,  which  is  a  factor  in  preventing  caries.  Almost  all  surfaces 
of  the  teeth  are  kept  clean  and  are  consequently  immune  to  caries.  If 
caries  does  occur  the  cavity  margins  do  not  require  to  be  extended 
appreciably  to  meet  areas  which  are  immune.  Others  have  teeth  which 
always  seem  to  have  what  might  be  called  a  scum  over  them,  with 
cavities  occurring  in  every  defect  of  enamel  and  on  surfaces  which 
would  be  immune  in  other  mouths.  Where  decay  seems  so  progres- 
sive, cavity  margins  must  be  extended  until  they  reach  the  immune 
areas  of  the  tooth's  surface  even  though  much  of  the  surface  must  be 
covered  by  filling. 

Month  Appearance. — ^The  very  appearance  of  the  mouth  often  helps 
the  operator  to  choose  the  character  of  operation.  A  certain  viscid 
tenacious  saliva,  abundant  in  quantity,  usually  indicates  rapid  decay 
and  demands  that  the  outlines  of  the  cavity  should  be  extended  far 
beyond  the  areas  of  contact  with  the  other  teeth.  Many  points  of  white 
or  yellowish- white   decay   on   smooth   surfaces   especially   in   labial. 


T70  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

buccal,  and  lingual  surfaces  is  indicative  of  a  marked  susceptibility 
and  demands  free  extension  of  cavity  outlines,  while  if  the  cavities  be 
dark  brown  or  black  in  color  and  are  found  only  in  fissures  the  outlines 
need  not  be  extended  so  freely.  Because  of  the  difficulty  of  keeping 
irregular  teeth  clean  cavities  in  such  cases  should  be  extended  fully. 
It  resolves  itself  into  this,  in  all  cases  where  decay  occurs,  that  part  of 
the  tooth's  surface  which  is  not  kept  clean  about  the  cavity  should  be 
included  within  its  outline. 

I.  The  outline  form  is  the  form  of  the  area  of  the  tooth's  surface  to 
be  included  within  the  outline  of  enamel  margins  of  the  finished  cavity. 
The  first  step  in  the  preparation  of  any  cavity  is  to  decide  as  far  as 
possible  the  extent  of  the  caries  which  in  a  measure  helps  to  locate  the 
outline  of  the  cavity.  The  extent  of  the  caries  helps  to  locate  the  outline 
only  in  simple  pit  cavities,  and  those  occurring  in  exposed  surfaces  and 
those  which  are  so  large  as  to  have  involved  all  the  defects  of  enamel 
and  susceptible  areas  of  the  tooth's  surface  under  consideration.  To 
find  out  the  extent  of  the  caries  it  is  necessary  to  break  down  the 
enamel  not  supported  by  dentin  except  perhaps  where  it  may  be  left 
for  esthetic  reasons  as  in  labial  and  buccal  cavities  in  incisors,  cuspids 
and  bicuspids.  The  loosened  and  soft  decaymay  be  removed  and  the 
cavity  washed  out  with  a  stream  of  tepid  water.  This  will  so  clear 
the  field  of  operation  that  a  better  judgment  can  be  made  as  to  the 
amount  of  sound  tissue  remaining,  the  condition  of  the  pulp  and  the 
proper  location  of  the  outline.  In  the  further  preparation  of  the  cavity 
it  is  well  to  have  the  rubber  dam  in  position  or  use  some  other  means  of 
keeping  the  cavity  dry. 

(a)  In  fissure  cavities  the  outline  must  include  all  the  fissures 
and  angular  grooves  radiating  from  the  caries  even  though  the  cavity 
be  but  small.  Such  a  cavity  usually  begins  because  of  a  defect  in  the 
continuity  of  the  enamel  surface  and  if  only  the  carious  portion  be  re- 
moved and  a  filling  inserted  the  defective  fissures  remaining  are  just  as 
likely  to  decay  as  originally.  It  is  found  that  unless  filling  materials 
are  polished  flush  with  the  enamel  surface  the  thin  edge  left  over  the 
margins  will  likely  be  a  point  of  leakage  and  later  decay.  If  angular 
grooves  are  left  radiating  from  a  cavity  it  is  impossible  to  so  polish  the 
filling  that  none  will  be  left  over  these  margins,  hence  it  is  better  to 
cut  them  out  and  include  them  in  the  cavity. 

(b)  Superficial  defects  of  the  enamel  about  cavities  should  be 
cut  out  until  sound  enamel  is  reached  and  in  some  cases  until  full 
length  rods  are  reached.  In  many  cavities  occurring  about  the  gum 
margins  there  is  an  area  of  whitened  or  defective  enamel  passing  around 


STEPS    IN   CAVITY    FORMATION.  17I 

the  tooth  which  if  not  cut  out  and  included  in  the  cavity  will  decay  in 
a  short  time  and  cause  the  loss  of  the  filling,  and  perhaps  the  confi- 
dence of  the  patient  in  filling  operations.  In  some  of  these  cases  the 
outer  ends  of  the  rods  are  worn  away  or  lost  by  the  effects  of  superficial 
decay  and  are  likely  to  cause  the  failure  of  the  filling  if  the  margin  pass 
across  it. 

(c)  Extension  for  Prevention. — The  general  rule  laid  down 
for  locating  the  margins  of  cavities  which  occur  in  proximal  surfaces 
is  to  extend  them  to  such  a  point  on  the  tooth's  surface  that  the  joint 
between  the  filling  and  the  enamel  may  be  in  immune  areas.  There 
may  be  some  exceptions  to  this  rule  in  rare  cases  but  if  cavity  margins 
are  allowed  to  come  against  adjoining  teeth  the  fillings  cannot  be  con- 
sidered more  than  temporary. 

Any  one  who  has  practised  dentistry  for  more  than  a  few  years 
cannot  help  having  observed  the  wisdom  of  extending  all  proximal 
cavities  buccally,  lingually,  and  gingivally  far  enough  to  bring  the 
margins  to  such  a  point  on  the  tooth's  surface  as  will  ensure  their  being 
kept  clean  or  protected  by  healthy  gum  tissue.  It  makes  but  little 
difference  whether  the  cavity  be  small  or  large  in  a  proximal  surface 
the  outline  should  be  well  beyond  any  contact  with  the  adjoining  tooth. 
This  extension  of  cavity  walls  through  sound  tissue  to  bring  the  margins 
to  immune  areas  is  known  as  extension  for  prevention. 

(d)  A  developmental  groove  or  another  cavity  should  not  be 
allowed  to  come  too  close  to  enamel  margins.  It  is  better  in  such 
cases  to  cut  out  the  groove  and  include  it  in  the  cavity.  The  rods  of 
the  enamel  in  such  cases  usually  stand  at  right  angles  to  the  surface 
which  is  faced  away  from  .the  cavity,  so  when  the  cavity  is  prepared 
they  are  left  without  support.  If  only  a  small  portion  of  enamel  be 
left  between  a  cavity  and  another  filling  it  is  almost  certain  to  become 
a  source  of  weakness  to  both  fillings.  Such  enamel  is  usually  more  or 
less  undercut  and  unsupported  by  dentin  and  the  seat  of  fracture 
during  the  insertion  of  the  gold. 

(e)  The  buccal  and  lingual  margins  of  proximal  cavities  in  bi- 
cuspids and  molars  should  be  as  nearly  parallel  as  possible  and  at  right 
angles  to  the  seat  of  the  cavity.  Such  a  preparation  makes  the  gin- 
gival wall  more  accessible  to  start  and  condense  the  first  portion  of  the 
filling.  Besides  it  brings  the  outline  into  full  view  during  the  building 
of  the  filling.  If  these  margins  and  the  walls  of  the  cavity  adjoining 
them  are  parallel  the  filling  material  as  it  is  condensed  will  not  draw 
away  from  the  margins  as  in  divergent  walls,  or  tend  to  fracture  the 
tooth  as  in  convergent  walls. 


172  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

(f)  The  outline  in  all  cavities  should  be  straight  lines  or  regular 
curves  because  it  is  much  easier  to  adapt  a  filling  material  to  a  regular 
margin  than  to  an  irregular  or  ragged  one.  Besides  they  are  said  to 
be  more  esthetic,  which  is  doubtful,  but  at  all  events  they  look  more 
like  the  work  of  a  good  mechanic. 

Technique. — To  obtain  the  proper  outline  of  a  cavity  it  is  nec- 
essary to  break  down  and  remove  all  enamel  not  supported  by  dentin. 
The  straight  chisel  in  the  hand  well  guarded  against  slipping  will  cut 
away  enamel  readily  if  the  edge  of  the  blade  is  made  to  insinuate  itself 
between  the  rods.  The  force  should  be  applied  in  the 
direction  of  the  long  axis  of  the  rods.  In  some  cases  the 
sharp  edge  of  the  blade  may  be  placed  against  the  wall  of 
enamel  and  the  edge  snapped  off  piece  by  piece  (Fig.  113). 
In  others  the  edge  of  the  chisel  may  be  placed  against  the 
enamel  and  given  a  quick  decisive  blow  with  a  mallet 
which  will  readily  fracture  the  enamel  (Fig.  114).  It  is 
well  to  be  careful  not  to  attempt  to  cut  off  more  at  once  than  will  easily 
be  cleaved  away  on  account  of  the  shock  from  the  mallet  which  may 
be  painful  to  the  patient  and  come  with  such  suddenness  as  to  cause 
doubt  of  the  operator's  skill.  A  chisel  in  the  automatic  mallet  will 
often  break  enamel,  but  like  hand  pressure  it  is  difficult  to  control. 
A  chisel  in  an  engine  mallet  will  break  enamel  rapidly  and  is  under 
control  but  violent  on  the  patient  if  a  blow  is  given  against  the  enamel 
which  does  not  chip  off.  The  final  planing  of  the  enamel  wall  to  bring 
it  to  evenness  must  be  done  with  a  chisel.  Cavities  in  proximal  sur- 
faces which  -require  extension  through  sound  tissue  are 
best  enlarged  by  cutting  the  dentin  out  under  the  enamel 
with  a  comparatively  small  bur  and  then  breaking  down 
the  enamel  with  the  chisel. 

Cutting  out  fissures. — Fissure  cavities  can  be  extended 
in  undecayed  enamel  by  cutting  a  narrow  slot  through 
the  groove  with  a  small  dentate  fissure  bur  ground  at  Fig.  114. 
the  point  on  two  sides  to  make  it  into  a  drill.  A  wornout,  inverted 
cone  bur  ground  to  the  same  form  will  cut  equally  well.  If  the 
hand-piece  be  given  a  swaying  motion  and  the  point  kept  sharp 
even  perfect  enamel  can  be  cut  rapidly.  If  it  be  found  that  the 
dentin  is  not  very  sensitive  the  drill  point  may  be  directed  rather 
under  the  enamel  which  seems  to  undermine  it  and  allow  it  to  cut 
easier.  It  is  important  that  the  drill  be  small,  a  large  drill  imparts 
too  much  jar  to  the  tooth.  Even  the  smallest  size  of  an  inverted 
cone  bur  so  ground  will  serve  every  purpose  because  once  the  enamel 


STEPS    IN    CAVITY    FORMATION.  1 73 

is  broken  the  edges  may  be  chipped  in  with  a  chisel  or  a  hatchet 
excavator.  A  small  thin  edged  carborundum  disk  in  the  straight 
hand  piece  for  bucco-lingual  fissures  and  in  the  right  angle  for  mesio- 
distal  fissures  will  open  them  up  rapidly  and  with  less  discomfort  to 
the  patient  than  fissure  burs.  In  certain  large  distal  cavities 
in  molars  the  buccal  and  lingual  walls  cannot  be  reached  with 
a  straight  chisel  and  a  curved  chisel  with  a  narrow  blade  cannot 
be  controlled  if  force  enough  be  applied  to  fracture  the  enamel.  The 
blade  is  almost  certain  to  drop  into  the  cavity  and  touch  sensitive  dentin 
or  perhaps  wound  a  living  pulp.  An  instrument  made  on  the. form 
of  a  broad  axe,  with  the  blade  short  and  wide  and  parallel  with  the  long 
axis  of  the  shaft  will  successfully  break  such  enamel  walls  without 
danger  to  the  pulp  or  the  gum  tissue. 

In  smooth  surface  cavities  in  exposed  positions  the  outline  may  be 
extended  with  dentate  inverted  cone  burs  by  placing  the  base  of  the 
cone  against  the  axial  wall  and  carrying  the  corner  of  the  bur  under 
the  enamel.  In  this  way  the  foundation  of  the  enamel  is  cut  first 
leaving  it  easily  cleaved  away. 

Final  Trimming  and  Planing. — ^The  final  trimming  or  planing  of 
the  enamel  wall  is  done  with  broad  bladed  chisels  holding  the  width 
of  the  blade  parallel  with  the  long  axis  of  the  rods.  Black's  side  in- 
struments will  shave  the  buccal  and  lingual  enamel  walls  of  molars, 
while  the  gingival  is  best  reached  with  a  Darby-Perry  chisel.  The 
enamel  walls  of  pit  and  fissure  cavities  are  best  trimmed  with  fissure 
burs  run  rapidly  and  held  at  right  angles  to  the  pulpal  wall.  If  access 
to  the  cavity  is  reasonably  good,  a  thin  carborundum  disk  will  rapidly 
cut  back  the  buccal  and  lingual  walls  and  leave  a  smooth  regular  sur- 
face. A  cone-shaped  carborundum  stone  with  a  square  end  in  the  right 
angle  will  extend  the  dentin  of  both  walls  and  square  the  seat  at  the 
same  time. 

2.  Softened  and  decalcified  dentin  should  next  be  removed  from  the 
cavity.  In  certain  rare  cases  a  portion  of  hard,  discolored  dentin  may 
be  left  when  its  removal  would  expose  a  living  pulp.  In  such  cases  a 
non-irritating  disinfectant  should  be  used  for  sufficient  length  of  time 
to  insure  disinfection  before  the  filling  is  inserted. 

Technique.— The  manner  of  removing  the  remaining  decayed 
tissue  depends  upon  the  character  of  the  tissue,  the  size  and  location 
of  the  cavity  and  the  sensibility  of  the  dentin.  In  shallow  cavities  in 
exposed  surfaces  where  the  dentin  is  usually  sensitive  a  deep  decisive 
cut  with  a  hatchet  excavator  in  one  corner  of  the  cavity,  followed  by 
prying  up  or  scooping  out  of  the  tissue  in  one  layer  is  less  painful  than 


174  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

to  attempt  to  remove  the  tissue  in  small  pieces.  In  large  cavities 
when  the  decay  reaches  close  to  the  pulp  it  is  better  to  go  around  the 
edges  with  spoon  excavators  flaking  up  the  decay  and  peeling  the 
layers  off  without  making  much  pressure.  After  the  decayed  tissue 
is  well  removed  down  to  the  solid  dentin  at  all  points  except  where 
the  pulp  comes  nearest  to  the  cavity,  then  take  a  large  spoon  excavator 
and  carefully  scrape  away  the  decalcified  dentin  until  hard  tissue  is 
reached.  This  can  be  done  without  pain  to  the  patient  if  little  or  no 
pressure  is  applied.  Usually  in  these  cavities  it  is  the  dentin  at  the 
dento-enamel  junction  which  is  most  sensitive.  In  certain  cavities 
of  dark  brown  or  black  decay  where  the  tissue  is  hard,  as  occasionally 
occurs  in  occlusal  cavities  in  molars  in  old  patients,  the  decay  may  be 
most  rapidly  removed  with  burs.  In  no  case  should  burs  be  used 
close  to  the  pulp.  In  fact  burs  are  of  little  or  no  value  in  removing 
decayed  tissue  except  where  it  is  hard.  Spoon  excavators  are  of  most 
general  use,  though  hatchets  and  burs  may  be  used  in  special  cases. 

3.  A  cavity  may  be  considered  of  proper  form  when  it  is  so  shaped 
that  it  can  be  conveniently  filled,  when  it  will  retain  the  filling  and 
when  its  walls  will  resist  any  stress  which  may  come  upon  them. 

(a)  For  convenience  a  cavity  should  be  so  formed  that  all  its  walls 
may  be  seen  directly  or  brought  into  view  with  the  mouth  mirror. 
Grooves  and  undercuts  should  be  avoided  in  a  completed  cavity  form. 
They  are  always  difficult  to  fill  and  add  very  little  to  the  retention  of 
the  filling,  and  are  a  source  of  weakness  to  the  walls.  Line  angles 
and  point  angles  should  not  be  so  small  and  acute  that  instruments 
cannot  reach  their  depths.  Proximo-occlusal  cavities  in  molars 
and  bicuspids  are  in  their  most  convenient  form  for  filling  when  they 
are  so  shaped  that  they  will  retain  the  filling  and  resist  the  stress  of 
mastication.  If  such  cavities  have  a  flat  seat  and  step,  parallel  buccal 
and  lingual  walls  and  a  dovetail  in  the  occlusal  surface,  they  are  then 
convenient  to  fill  with  whatever  material  is  desired.  Cavities  in 
incisors  and  cuspids  require  perhaps  some  slight  modification  of  a 
gingivo-labio-axial  point  angle  and  gingivo-linguo-axial  point  angle 
to  make  it  possible  to  more  conveniently  start  a  gold  filling.  These 
angles  are  made  more  acute  and  the  corner  is  cut  more  deeply  than 
is  necessary  for  retention.  They  may  be  truly  called  convenience 
angles.  In  some  cavities  difficult  of  access  it  is  often  more  convenient 
to  cut  away  a  wall  or  to  extend  an  outline  so  as  to  bring  the  walls  into 
full  view.  The  labial  surfaces  of  incisors  and  cuspids  should  not  be 
cut  away  for  convenience  of  access  to  a  small  proximal  cavity.  In 
the  majority  of  these  cases  it  is  better  to  separate  the  teeth  until  access 


STEPS    IN    CAVITY    FORMATION.  1 75 

can  be  had  to  properly  prepare  the  cavity  and  insert  the  filling,  while 
in  other  cases  the  lingual  surface  may  be  cut  into  for  convenience  of 
access. 

Technique. — The  general  technique  of  obtaining  the  outline  form 
having  been  described  it  is  not  necessary  to  discuss  more  than  what  is 
specially  done  for  convenience.  A  cavity  with  a  good  outline  is  easily 
filled.  In  many  cavities  having  penetrating  decay  it  will  often  be  more 
convenient  to  fill  any  irregularities  or  pits  not  used  for  retention  with 
cement,  leveling  up  the  walls.  Often  a  buccal  plate  of  enamel  in  a 
mesio-occlusal  cavity  in  an  upper  bicuspid  is  left  for  appearance 
sake  though  the  dentin  is  gone  from  beneath  it.  The  loss  of  the 
dentin  leaves  such  a  deep  groove  at  the  junction  of  the  axial  and  buccal 
walls  that  it  is  very  inconvenient  and  difficult  to  fill  it  with  gold.  In 
such  cases  it  is  much  better  to  fill  the  grooves  with  cement  and  square 
up  the  buccal  and  lingual  walls  so  that  they  may  be  parallel.  For 
convenience  of  starting  a  cohesive  gold  filling  in  proximal  cavities 
in  incisors  and  cuspids  a  No.  ^  or  No.  i  inverted  cone  bur,  which  is 
held  parallel  with  the  long  axis  of  the  tooth  as  it  is  carried  from  labial 
to  lingual  to  form  a  flat  seat  for  a  filling,  may  be  swayed  toward  the 
labial  as  it  is  carried  to  the  labio-gingivo-axial  angle,  and  as  the  bur 
approaches  the  depth  required  it  should  be  swayed  to  the  lingual  and 
carried  slightly  toward  the  incisal.  By  this  movement  a  deep  acute 
angle  is  cut  which  has  the  general  direction  of  the  greatest  amount  of 
tooth  tissue  avoiding  the  pulp.  This  acute  angle  is  in  a  like  manner 
cut  in  the  gingivo-linguo-axial  angle.  With  acute  angles  cut  in 
opposite  walls  in  the  seat  of  any  cavity  there  should  be  no  difficulty 
in  starting  a  cohesive  gold  filling.  These  may  be  truly  called  con- 
venience angles  though  they  are  large  enough  to  assist  in  the  retention 
of  the  filling.  These  angles  are  easily  filled  and  securely  hold  the  gold 
in  position  while  more  may  be  built  upon  it.  The  small  pits  drilled 
at  random  in  the  seat  of  the  cavity  as  has  been  too  often  the  practice 
are  difficult  to  fill  and  not  always  secure  when  filled.  There  seems 
to  be  a  growing  tendency  among  operators  who  do  not  wish  to  expose 
gold  on  labial  surfaces  to  cut  the  lingual  surface  freely  away,  making 
a  dovetail  in  the  enamel  for  retention.  This  is  really  a  convenience 
form. 

(b)  Resistance  form  is  .that  shape  given  a  cavity  intended  to 
afford  such  a  seat  for  the  filling  as  will  best  enable  it  to  withstand  the 
stress  brought  upon  it  in  mastication.  Its  importance  depends  upon 
the  area  of  the  surface  of  the  filling  exposed  to  occlusion,  and  the 
strength  of  the  closure  of  the  jaws.     The  general  rule  in  foundation 


176  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

construction  is  to  keep  as  nearly  a  flat  base  as  possible.  Foundations 
made  to  resist  heavy  weights  and  tipping  stress  are  flat.  A  cone- 
shaped  base  in  a  pulpless  bicuspid  or  molar  decayed  mesio-occluso- 
distally  has  often  been  the  cause  of  a  fracture  of  the  root.  In  such 
cases  the  filling  acts  as  a  wedge,  cleaving  the  weaker  wall.  The  seat 
of  occlusal  cavities  should  be  flat  and  at  right  angles  to  the  stress 
coming  upon  it,  likewise  cavities  in  proximo-occlusal  surfaces  of 
molars  and  bicuspids  should  have  a  flat  seat  and  step  to  resist  the 
heavy  stress  of  occlusion  and  the  tipping  stress  which  comes  upon 
these  fillings.  It  is  not  often  realized  by  operators  how  much  stress 
some  fillings  may  be  called  upon  to  resist.  In  strong  men  a  single 
molar  may  occasionally  have  a  force  of  from  two  hundred  to  two 
hundred  and  fifty  pounds  applied  to  it.  The  closure  of  incisors  of 
course  is  much  less,  but  the  anchorage  for  a  filling  in  these  teeth  is  less. 
The  biting  off  of  a  crust  of  bread  and  its  mastication  will  involve  a 
pressure  of  from  100  to  150  lbs.,  while  an  ordinary  beefsteak  requires 
seventy-five  pounds  of  pressure  on  an  area  the  size  of  the  human  teeth 
to  cut  through  it.  In  accidents  of  a  piece  of  lead  in  canned  goods, 
or  shells  or  bones  in  flesh,  a  filling  may  receive  the  whole  weight  of  the 
closure.  Pulpless  teeth,  crowns  and  dentures  have  much  less  force 
applied  to  them  than  normal  teeth.  It  would  seem  that  when  the 
pulp  of  a  tooth  is  lost  the  pericemental  membrane  loses  some  of  its 
power  to  resist  pressure  without  injury.  Hence  fillings  antagonizing 
with  pulpless  teeth  crowns  and  dentures  need  not  be  so  securely  seated 
as  those  opposing  sound  teeth.  In  deciding  what  amount  of  seating 
a  filling  should  require  the  force  of  the  closure  of  the  jaws  must  be 
well  studied.  Also  the  teeth  antagonizing  the  filling  and  the  area 
of  the  filling  exposed  to  occlusion.  It  is  obvious  that  labial,  buccal, 
lingual,  and  small  proximal  cavities  in  incisors  and  cuspids  do  not 
require  to  be  securely  seated  because  the  surfaces  of  these  fillings 
are  not  exposed  to  the  forces  of  mastication.  No  one  thing  has 
done  more  for  the  stability  of  fillings  than  the  study  of  the  forces  of 
the  closure  of  the  jaws  and  the  introduction  of  proper  methods  of 
seating  fillings  to  resist  that  force. 

Technique. — The  inverted  cone  bur,  the  fissure  bur,  the  chisel, 
the  hatchet  and  the  hoe  excavators  are  the  only  instruments  which 
can  be  used  to  form  a  flat  seat  in  cavities  to  resist  the  force  coming  upon 
the  filling.  Round  burs  and  spoon  excavators  have  no  place  in  form- 
ing the  seat  of  a  cavity.  The  seat,  the  step,  and  the  lateral  walls 
must  be  definite,  joining  each  other  with  right  angles  or  acute  angles. 
The  seat  in  molar  and  bicuspid  cavities  may  be  cut  flat  from  buccal 


STEPS    IN    CAVITY    FORMATION.  I77 

to  lingual  and  from  the  enamel  margin  to  the  axial  wall  with  an  in- 
verted cone  bur  about  one  millimeter  in  diameter.  As  this  bur  is 
carried  back  and  forth  from  buccal  to  lingual  there  is  often  some 
difficulty  in  keeping  it  from  jumping  out  of  the  cavity,  and  perhaps 
winding  up  the  septum  of  rubber  dam  between  the  teeth,  or  wounding 
the  gum,  or  perhaps  cutting  dangerously  near  the  pulp.  The  diffi- 
culty of  holding  a  bur  in  such  a  position  is  increased  with  the  increase 
of  the  size  of  the  bur  and  also  by  placing  it  in  the  right-angled  hand- 
piece. If,  after  all  the  overhanging  enamel  is  broken  down  and  the 
softened  decay  removed,  the  Ivory  or  Hinicker  matrix  be  adjusted, 
a  bur  can  then  be  held  in  the  base  of  the  cavity  without  fear  of  accident 
in  one  direction  at  least.  It  is  generally  well  to  use  a  small  bur, 
cutting  the  dentin  only,  and  then  cut  away  the  enamel  with  Black's 
side  instruments  or  Darby-Perry  chisels.  This  will  leave  a  wide 
flat  seat.  The  step  is  usually  partly  formed  with  cement  and  as 
the  last  part  of  its  formation  an  inverted  cone  bur  in  the  right  angle 
may  be  carried  over  the  whole  step.  The  seat  of  incisor  cavities  is 
formed  in  the  same  way  only  using  much  smaller  burs;  about  a  half 
millimeter  inverted  cone  is  more  suitable  for  laterals  and  some  centrals, 
(c)  Retention  form  is  that  shape  given  a  cavity  which  will  prevent 
the  filling  from  being  dislodged.  This  is  largely  provided  for  in  the 
resistance  form  and  to  some  extent  in  the  convenience  form,  but  in 
certain  cavities  the  filling  might  resist  the  direct  stress  upon  it  and  yet 
be  easily  displaced  with  slight  lateral  force.  Retention  form  is  pro- 
vided for  in  proximo-occlusal  cavities  in  molars  and  bicuspids  by  a 
dovetail  in  the  occlusal  surface  and  by  providing  parallel  w-alls  or 
perhaps  walls  slightly  undercut.  Proximal  cavities  in  incisors  and 
cuspids  which  do  not  involve  the  incisal  angle  do  not  need  more  than 
a  flat  seat  deepened  at  the  gingivo-labio-axial  and  gingivo-linguo- 
axial  angles,  with  a  slight  undercut  at  the  junction  of  the  labial  and 
lingual  walls  at  the  incisal.  Cavities  which  involve  the  incisal  angle 
should  be  provided  with  a  step  if  much  stress  is  to  come  upon  the 
fillings.  For  many  years  operators  have  been  chiefly  concerned  in 
the  retention  of  fillings,  only  having  regard  to  what  might  tip  them 
from  the  cavity,  not  thinking  that  the  greatest  force  in  dislodging 
fillings  is  the  direct  stress  of  the  closure  of  the  jaws.  The  more  fillings 
failed  the  more  and  the  deeper  were  made  the  pits,  grooves  and  under- 
cuts. The  pits  did  not  contain  enough  filling  material  to  have  strength 
to  resist  the  stress,  and  the  grooves  and  undercuts  often  cut  clear 
through  the  dentin,  leaving  only  the  enamel  for  retention  which 
frequently  fractured.     The  thoughtless  operator  has  an  idea  that^if 


178  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

he  uses  a  large  round  bur  in  the  center  of  the  tooth  making  the  cavity 
larger  inside  than  at  the  margins  the  filling  cannot  get  out.  This 
might  succeed  if  the  enamel  were  not  so  friable  when  unsupported 
by  sound  dentin.  The  surest  way  to  make  a  cavity  which  will  retain 
a  filling  is  to  study  carefully  the  forces  which  may  come  upon  it  to 
dislodge  it.  Estimate  the  strength  of  the  cavity  walls  and  then  so 
shape  the  cavity  that  its  seat  or  foundation  will  be  opposite  the  stress 
applied  and  its  retention  cut  in  the  direction  of  the  greatest  amount 
of  dentin,  and  if  undercuts  are  used  place  them  in  opposite  walls  of  the 
cavity.  In  general  the  retention  should  be  as  near  the  point  of  stress 
as  possible,  and  the  area  of  the  seat  and  step  equal  to  the  area  of  the 
filling  exposed  to  the  occlusion. 

Technique. — A  cavity  is  usually  shaped  to  resist  tipping  stress 
with  the  same  instruments  as  are  used  to  make  the  resistance  form. 
Occlusal  cavities  in  molars  and  bicuspids  require  parallel  walls,  and 
at  opposite  points  a  slight  undercut  which  can  be  made  with  the  inverted 
cone  bur  as  its  shaft  is  held  at  right  angles  to  the  pulpal  wall.  The 
only  force  which  might  remove  this  filling  would  be  a  lifting  force 
from  the  adhesion  of  some  sticky  substance  such  as  taffy.  Proximo- 
occlusal  cavities  in  molars  and  bicuspids  cannot  be  retained  to  any 
extent  by  grooves  or  undercuts.  The  dovetail  in  the  occlusal  surface 
which  is  easily  cut  with  a  cross  cut  fissure  bur  or  inverted  cone  bur 
is  all  that  is  necessary.  In  some  bicuspids  retentive  form  may  be 
obtained  in  the  occlusal  surface  by  deepening  the  step  at  the  point 
farthest  from  the  proximal  cavity  with  an  inverted  cone  bur  slightly 
undercutting  the  buccal  and  lingual  walls.  Proximal  cavities  in 
incisors  and  cuspids  may  have  grooves  extending  out  from  the  point 
angles  for  retention.  As  the  inverted  cone  bur  is  sunk  into  the  angles 
it  may  be  carried  up  the  labial  and  lingual  walls  a  short  distance 
making  a  groove.  In  many  of  these  cases  an  obtuse  angle  hatchet 
or  hoe  may  be  used  to  cut  a  definite  angular  groove  in  these  walls. 
The  retention  towards  the  occlusal  is  best  cut  with  a  small  contra- 
angled  hatchet  excavator.     No.  27,  S.  S.  W.,  is  a  very  suitable  size. 

4.  The  proper  bevel  and  polish  of  the  enamel  wall  of  a  cavity 
is  of  prime  importance  because  the  permanency  of  the  filling  depends 
so  much  upon  the  joint  between  the  filling  and  the  tooth.  A  good 
working  knowledge  of  the  histology  of  the  enamel  is  essential  to 
obtain  the  correct  bevel  of  the  enamel  wall  at  all  points. 

The  enamel  is  composed  of  rods  cemented  together  by  a  less  dense 
substance  than  that  composing  the  rods.  In  consequence  of  the  cement- 
ing substance  being  less  strong  than  the  rods  the  structure  is  likely 


STEPS    IN    CAVITY    FORMATION.  I^q 

to  cleave  between  the  fibers.  The  rods  are  difficult  to  cut  across  or 
hard  to  wear  down  from  their  ends  but  easily  split,  if  the  cleaving 
force  is  in  the  direction  of  the  long  axis.  This  is  of  importance  in 
breaking  down  enamel  to  open  into  a  cavity.  If  a  chisel  be  directed 
against  the  enamel  so  that  the  rods  are  split  apart  little  force  is  re- 
quired. The  rods  are  more  or  less  parallel  in  their  outer  half 
while  in  their  inner  half  they  are  interlaced  and  tangled  together. 
In  some  teeth  the  rods  radiate  from  the  dentin  almost  parallel,  while 
in  others  they  are  wavy  and  are  interlaced  a  great  deal.  It  is  this 
variation  in  the  interlacing  of  the  fibers  that  accounts  for  the  difference 
in  the  degree  of  resistance  enamel  has  for  cutting  instruments.  It  was 
formerly  believed  that  enamel  which  was  very  resistant  to  cutting 
instruments  was  harder  because  it  contained  more  lime  salts  than 
that  which  cut  more  easily.  This  was  shown  to  be  a  fallacy  by  Dr. 
Black,  who  demonstrated  that  the  so-called  soft  teeth  had  not  less 
lime  salts  but  seemed  to  be  soft  because  the  enamel  rods  were  straight 
and  consequently  easily  split  apart,  while  the  so-called  hard  teeth 
were  merely  hard  because  the  fibers  of  enamel  were  interlaced  and 
tangled  together  much  like  the  fibers  of  wood  in  a  pine  knot,  and  any 
attempt  to  cleave  them  is  difficult  because  no  matter  in  what  direction 
the  attempt  is  made  the  rods  must  be  cut  across. 

The  direction  of  the  enamel  rods  may  be  said  to  be  from  the  center 
of  the  tooth  to  the  surface.  The  rods  are  generally  perpendicular 
to  the  surface  but  there  are  many  locations  where  they  approach  the 
surface  at  a  decided  inclination.  At  a  line  about  the  center  of  a 
molar  or  bicuspid  the  rods  are  perpendicular  to  the  surface,  but  as  the 
occlusal  surface  is  reached  the  rods  become  more  and  more  inclined 
toward  the  cusps  where  they  become  parallel  with  the  long  axis  of  the 
tooth  and  perpendicular  to  the  tip  of  the  cusp.  Likewise  as  the  gingival 
is  reached  the  rods  become  more  and  more  inclined  toward  the  root.  It 
is  clear  from  these  facts  that  a  cavity  in  an  axial  surface  coming  close 
to  the  cusp  or  marginal  ridge  cannot  have  its  occlusal  wall  perpendicu- 
lar to  the  axial  surface  without  leaving  many  enamel  rods  not  sup- 
ported by  dentin.  A  decided  bevel  should  be  given  enamel  walls 
at  these  points  which  may  make  the  filling  material  so  thin  that  it 
may  flare  up  from  the  margin.  Any  attempt  to  make  an  occlusal 
wall  of  a  cavity  close  to  the  occlusal  surface  is  fraught  with  many 
chances  of  failure.  It  is  usually  advisable  to  cut  through  to,  and 
include  some  of,  the  occlusal  surface. 

The  enamel  rods  incline  toward  pits  and  fissures  and  as  they  pass 
from  a  fissure  in  the  occlusal  surface  of  a  bicuspid  or  molar  toward 


l8o  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

the  cusps,  the  rods  incline  more  and  more  until  they  are  perpendicular 
to  the  tip  of  the  cusp.  Thus  a  groove  or  fissure  which  is  not  cut  out 
very  widely  requires  only  parallel  walls  to  protect  its  margins,  while 
a  cavity  in  the  occlusal  surface  of  a  bicuspid  which  is  cut  widely 
enough  to  approach  the  cusps  needs  a  good  deal  of  bevel. 

In  incisors  and  cuspids  a  line  around  the  crown  at  the  junction  of 
the  gingival  with  the  middle  third  will  find  the  rods  pretty  generally 
perpendicular  to  the  tooth's  surface.  But  as  the  incisal  is  reached 
the  inclination  of  the  rods  becomes  greater  and  greater  until  they 
reach  the  cutting  edge  where  they  are  parallel  with  the  long  axis  of 
the  tooth.  The  inclination  in  the  incisal  third  is  often  as  much  as 
30  to  40  degrees.  In  proximal  surfaces  the  degree  of  inclination  of 
the  rods  depends  upon  the  abruptness  with  which  these  surfaces  join 
the  incisal  edge.  The  more  rounded  the  corner  the  more  the  rods 
are  inclined  toward  the  incisal.  Thus  on  the  distal  surfaces  of  laterals 
the  inclination  is  greater  than  on  the  mesial  surface.  Proximal  cavities 
coming  close  to  the  incisal  edge  in  these  teeth  require  so  much  bevel 
to  remove  the  short  rods  that  the  margin  of  the  filling  is  endangered 
by  being  too  thin. 

Passing  around  the  incisors  and  cuspids  the  rods  are  generally 
perpendicular  except  at  the  junction  of  the  proximal  and  lingual 
surfaces,  where  the  rods  are  inclined  towards  the  marginal  ridge  and 
become  rapidly  inclined  the  opposite  way  on  the  lingual,  and  con- 
sequently when  this  ridge  is  approached  it  should  be  cut  well  back 
because  the  rods  are  not  supported. 

Cavity  walls  cut  in  the  incisal  surface  of  incisors  and  cuspids 
are  well  protected  even  though*  not  brought  down  on  the  labial  or 
lingual  surfaces  because  of  the  inclination  of  the  rods. 

Since  the  enamel  rods  are  not  always  parallel  with  each  other  nor 
always  at  right  angles  to  the  plane  of  the  tooth's  surface,  and  since 
all  filling  materials  are  not  always  of  equal  strength  with  the  enamel, 
it  is  not  advisable  to  make  the  cavo-surface  angle  a  right  angle.  But 
instead  the  outer  half  of  the  enamel  wall  should  be  cut  back  until 
the  angle  formed  by  the  junction  of  the  enamel  wall  and  the  tooth's 
surface  should  be  greater  than  a  right  angle.  The  number  of  degrees 
greater  depends  upon  the  inclination  of  the  enamel  rods,  the  friability 
of  the  enamel,  the  force  to  come  against  it  and  the  kind  of  filling 
material  to  be  used.  Gold  fillings  have  the  greatest  protecting  power 
for  enamel  walls  and  are  the  most  likely  to  cause  fracture  or  crumbling 
of  the  edge  during  insertion,  consequently  cavities  prepared  for  the 
insertion  of  gold  require  more  bevel  than  those  prepared  for  amalgam 


STEPS    IN    CAVITY    FORMATION.  l8l 

or  porcelain.  Cavities  prepared  for  gold,  where  much  force  may 
come  upon  the  edges  and  the  enamel  is  friable,  require  more  bevel 
than  cavities  which  occur  in  surfaces  where  less  force  may  fall.  Teach- 
ers and  writers  of  operative  dentistry  have  always  said  much  on 
beveling  enamel  walls  but  rarely  given  the  student  any  adequate 
idea  of  how  much  bevel  a  wall  should  receive.  This  idea  is  hard  to 
impart  in  words  unless  accompanied  with  diagrams  and  a  statement 
of  the  number  of  degrees.  Every  student  has  an  idea  of  what  a  right 
angle  is,  and  he  knows  when  a  cavo-surface  angle  is  a  right  angle. 
Now  if  he  will  divide  a  right  angle  into  sixteenths,  eighths,  sixths,  and 
fourths  he  will  have  an  idea  what  is  meant  when  the  bevel  is  to  be  5  to 
25  degrees.  This  means  that  the  cavo-surface  angle  is  90  degrees 
plus  the  number  of  degrees  of  bevel  (which  is  for  example  25)  or  115 
degrees.  As  a  rule  when  a  lecture  is  given  to  a  class  of  students 
on  beveling  enamel  walls  there  will  be  many  of  them  go  to  the  extreme 
in  bevels.  This  must  be  guarded  against  lest  the  filling  material 
be  too  thin  on  the  edge. 

Technique. — Beveling  and  smoothing  enamel  walls  require  so 
much  skill  and  deft  manipulation  that  it  is  only  after  repeated  trials 
in  cases  where  the  results  can  be  examined  with  a  large  magnifying 
glass  that  an  operator  can  be  at  all  sure  of  results. 

A  disk  is  the  most  suitable  instrument  to  bevel  and  polish  enamel 
walls  but  unfortunately  its  range  is  limited.  There  are  really  but  few 
cavity  walls  which  can  be  reached  at  the  proper  angle  with  a  disk. 
It  will  reach  the  labial,  lingual  and  buccal  enamel  walls  in  large  proxi- 
mal cavities  but  not  the  gingival,  and  only  occasionally  the  occlusal 
The  beginner  is  certain  to  round  the  cavo-surface  angle  with  a  disk 
unless  he  bears  in  mind  that  the  disk  must  not  be  pressed  against  the 
wall,  but  must  be  held  in  position  to  cut  the  rods  parallel  with  their  long 
axis,  allowing  no  wabbling  of  the  hand-piece,  mandrel  or  disk.  When 
the  rods  are  thus  cut  the  hand-piece  is  held  at  the  necessary  angle  to 
cut  the  bevel  required.  Often  too  much  bevel  is  cut  in  large  proxima 
cavities,  by  allowing  the  disk  to  go  too  close  to  the  gingival  wall.  At 
the  junction  of  the  gingival  wall  with  the  proximal  walls  the  rods  are  in 
such  a  direction  that  the  disk  cannot  possibly  reach  them  to  give  them 
the  proper  bevel.  The  gingival  enamel  wall  must  be  trimmed  and 
beveled  with  a  bur  or  chisel.  A  disk  in  the  right  angle  will  reach  en- 
amel walls  in  molars  and  bicuspids  to  better  advantage  in  many  cases 
than  the  straight  hand-piece.  j 

The  next  most  suitable  instrument  and  the  most  universally  applic- 
able is  the  chisel.     As  the  walls  are  planed  down  parallel  with  the 


l82  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

long  axis  of  the  rods  they  may  then  be  shaved  down  to  the  proper 
bevel.  The  instrument  must  be  held  firmly  and  not  allowed  to  turn 
or  catch  and  jump  as  it  is  carried  along  the  enamel  wall. 

The  bur  is  very  universal  in  its  application  in  trimming  and  beveling 
enamel  walls  but  can  never  leave  as  smooth  and  uniform  a  margin  as 
the  disk.  In  all  small  cavities  in  pits  and  fissures,  and  in  labial  and 
lingual  surface  cavities  it  is  the  only  instrument  that  can  be  used. 
In  the  majority  of  such  cavities  the  walls  are  cut  back  with  a  bur  as 
the  cavity  is  being  prepared.  The  bevel  may  be  made  with  a  straight 
cut  fissure  bur  run  rapidly.  The  gingival  enamel  wall  in  proximal 
cavities  may  be  best  trimmed  with  a  round  bur,  and  it  is  recommended 
by  Johnson  for  trimming  the  walls  in  occlusal  cavities  in  molars  and 
bicuspids. 

The  strip  has  a  very  limited  use  in  smoothing  enamel  walls.  It 
may  be  used  in  proximal  cavities  in  incisors  which  do  not  involve  the 
incisal  edge  but  extend  well  onto  the  labial  and  lingual  surfaces.  In 
this  position  a  strip  held  tight  and  passed  back  and  forth  from  labial 
to  lingual  without  allowing  it  to  be  lapped  around  the  tooth  will  smooth 
the  margin  as  nothing  else  will. 

5.  The  toilet  or  putting  the  final  touches  on  the  prepared  cavity 
should  include  a  close  scrutiny  of  the  condition  of  the  tissue  covering 
the  pulp  and  removing  any  dust  or  chips  which  may  have  collected  in 
the  cavity. 

If  the  cavity  wall  be  at  all  close  to  the  pulp  it  is  well  to  go  over  it 
with  a  large,  sharp  spoon  which  will  remove  any  remaining  de- 
calcified dentin.  Some  care  is  needful  lest  so  much  pressure  be  applied 
as  will  cause  pain.  It  is  usual  to  cover  such  a  pulpal  or  axial  wall 
with  cement  and  then  form  this  up  as  if  it  were  a  wall  of  dentin.  The 
cavity  may  now  be  dried  thoroughly  from  a  blast  of  warm  air  which 
will  remove  loose  chips,  but  if  moisture  has  been  allowed  in  the  cavity 
some  of  the  chips  will  be  so  attached  to  the  walls  and  crevices  that 
they  will  not  be  removed  by  a  blast  of  warm  air.  In  such  cases  a 
piece  of  dry  cotton  rubbed  around  the  walls  will  loosen  the  debris  and 
then  it  can  be  blown  away.  Alcohol  is  often  used  to  assist  in  drying 
a  cavity  but  in  sensitive  teeth  the  patient  receives  a  shock  from  the 
rapid  evaporation  of  the  alcohol. 

INSTRUMENTS. 

While  it  is  of  importance  to  know  how  to  prepare  a  cavity  it  is  of 
almost  equal  importance  to  know  what  instruments  to  use  and  how 


INSTRUMENTS.  1 83 

to  use  them.  The  study  of  instruments  and  how  to  use  them  is  no 
small  part  of  the  preparation  to  practise  dentistry.  We  are  known 
by  our  tools.  A  fifteen  minutes'  examination  of  a  dentist's  operating 
equipment  should  satisfy  any  one  as  to  his  standing  as  an 
operator.  Our  instruments  are  of  such  importance  to  us 
that  they  deserve  much  of  our  attention  in  selection,  arrange- 
ment and  keeping  in  order. 

An  instrument  is  divided  into  handle,  shank,  blade  and 
cutting  edge.     (Fig.  115.) 

The  handle  is  that  part  which  is  grasped  while  the 
instrument  is  being  used. 

The  shank  is  that  part  connecting  the  handle  with  the 
working  point  or  cutting  edge. 

The  working  point  or  cutting  edge  is  that  part  of  the  in- 
strument which  comes  in  contact  with  the  material  worked  upon. 

If  the  working  point  be  fiat  and  sharp  the  portion  widened 
to  bring  out  this  form  is  called  the  blade. 

For  convenience  of  communication  instruments  are  classi- 
fied as  excavators,  pluggers,  scalers,  trimmers,  separators, 
polishers,  clamps,  burs,  drills,  burnishers,  etc.  These  names 
denote  the  purpose  or  the  use  of  the  instrument.  If  we  wish 
to  further  describe  an  instrument  we  say  "hatchet"  or  "spoon" 
excavator,  "right  angle,"  "contra  angle,"  or  "cow  horn" 
plugger.     These  refer  to  the  form  of  blade  or  shank. 

Chisels  which  are  used  for  cutting  or  chipping  away 
enamel  have  their  cutting  edges  at  right  angles  to  the  shaft 
and  are  sharpened  by  cutting  or  grinding  only  one  plane  of 
the  blade. 

Hoes  have  the  cutting  edge  at  right  angles  to  the  shaft 
but  the  shank  is  so  bent  that  the  edge  is  looking  towards  the 
opposite  end  of  the  shaft,  and  the  bevel  to  form  the  cutting 
edge  is  at  the  expense  of  that  part  of  the  blade  away  from  the 
handle.     They  are  used  only  with  a  drawing  motion. 

Hatchets  have  the  cutting  edge  parallel  with  the  long  axis 
of  the  shaft  and  the  cutting  edge  is  formed  by  cutting  or  grind- 
ing both  planes  of  the  blade.  The  shanks  are  made  at  various 
angles  to  bring  the  edge  within  reach  of  the  cavity  walls. 

Spoons  are  really  not  spoons  in  the  true  sense  of  the  word.  ^^^ 
At  one  time  they  were  made  that  they  would  dip  up  fluid  but  they 
are  not  now  so  made.  There  is  no  concavity  in  the  blade.  They 
have    shanks  of  various  curves    to   make  the  blades  reach  into  the 


'/J 


i84 


PREPARATION    OF    CAVITIES    FOR    FILLINGS. 


various  depths  of  cavities.  Spoons  are,  with  the  chisel,  the  most  use- 
ful instruments  in  our  equipment.  They  will  remove  softened  decay 
to  best  advantage  and  will  also  cut  decalcified  dentin. 

There  are  gingival  margin  trimmers  and  side  instruments  which 
are  modifications  of  the  chisel  with  shanks  formed  so  as  to  bring 
the  working  edge  into  positions  where  the  ordinary  chisel  will  not 
reach. 


\l 


•^ 


Figs.  ii6. 


119, 


122.    123. 


124. 


125. 


Figs.  128.    129    130.     131 


135-  136. 


While  it  is  desirable  to  have  every  form  and  variety  of  instrument 
that  will  assist  in  any  way  in  operating,  it  is  at  the  same  time  desirable 
to  have  as  few  mstruments  as  will  fulfil  the  requirements.  It  will  be 
found  that  the  most  useful  instruments  for  all  cavities  in  molars  and 
bicuspids  will  be  chisels,  spoons  and  burs,  while  incisors  will  demand 
the  small  hatchets  in  addition. 

Below  is  an  equipment  of  cutting  instruments  suflEicient  to  begin 
with  and  to  fill  most  requirements.     (Figs.  116  to  140.) 


BURS. 
THE  DENTAL  ENGINE. 


185 


The  dental  engine  is  classified  as  an  instrument  used  in  the  prepa- 
ration of  cavities.  While  it  may  not  be  used  to  any  extent  in  the 
preparation  of  a  given  cavity  yet  it  is  indispensable  to  the  up-to-date 
operator.  Other  things  being  equal  the  operator  who  uses  the  dental 
engine  the  least  will  please  his  patients  the  most.  The  dental  engine 
should  only  be  used  for  that  part  of  the  preparation  of  a  cavity  which 
cannot  be  conveniently  done  by  hand.  If  such  a  rule  were  followed 
in  practice  patients  would  not  dread  dental  operations.  There  are 
two  general  forms  of  engines  which  affect  operations  to  a  marked 
extent,  the  all  cord  engine  and  the  flexible  cable.  The  all  cord  engine 
carries  the  bur  forward  without  any  jar  or  shock,  while  the  flexible 
cable  usually  winds  up  or  springs  back  as  pressure  is  brought  upon 
the  instrument,  thus  the  bur  is  rotated  with  a  series  of  stops  and  rapid 
turnings  which  jar  the  tooth  and  unnerve  the  patient.  The  all  cord 
engine  is  not  so  convenient  to  reach  diflfiicult  locations  hence  its  want 
of  popularity. 


142. 


143- 


144. 


145- 


BURS. 

Only  small  burs  should  be  used  in  the  cable  engine;  those  more 
than  one  and  a  half  millimeters  in  diameter  should  not  be  used  in 
teeth  with  living  pulps  or  those  with  a  sensitive  peridental  membrane. 
There  are  many  forms  of  burs  and  drills  used  in  cavity  formation  but 
the  most  useful  is  the  inverted  cone.  (Fig.  141.)  The  round  bur  which 
has  been  used  so  extensively  has  no  place  in  cutting  that  part  of  the 
cavity  where  a  bur  is  indispensable.  A  bur  should  never  be  used  to 
remove  softened  decay  because  spoon  excavators  will  do  it  better. 
The  round  bur  and  the  cone  bur  are  useful  to  open  into  a  pulp  chamber 
when  the  pulp  has  been  desensitized  or  devitalized.  (See  Figs.  142 
and  143.)  The  form  of  the  blades  of  a  bur  has  something  to  do  with 
the  rapidity  of  its  cutting.  The  dentate  bur  cuts  enamel  more  rapidly 
than  the  plain  blade.  There  is  a  dentate  pear-shaped  bur  that  cuts 
enamel  better  than  any  other  form.     (Fig.  i44-) 


i86 


PREPARATION    OF    CAVITIES    FOR    FILLINGS. 


The  inverted  cone  bur  has  the  great  advantage  of  being  capable 
of  being  made  into  other  forms  which  are  as  useful  as  the  original. 
Burs  cannot  be  sharpened  to  make  it  pay  at  present  prices  but  the 
operator  can  in  a  moment  convert  a  dull  bur  into  a  most  useful  instru- 
ment for  cutting  out  fissures  or  drilling  out  old  fillings.  A  bur  which 
has  once  cut  enamel  should  never  again  be  used  to  cut  sensitive  dentin. 
It  has  lost  its  keen  edge.  Burs  should  be  arranged  in  the  bur  rack  as 
new  ones,  those  used  on  dentin  a  few  times,  those  used  on  enamel  and 
those  only  useful  to  grind  into  drills,  etc.  Dull  fissure  burs  can  be 
flattened  on  opposite  sides  and  the  end  sharpened  into  a  drill  point. 
(Fig.  146.)  Dull  inverted  cone  burs  may  be  ground  square  across 
the  end,  thus  cutting  the  blades  off  the  end  and  bringing  them  far 
enough  up  the  shaft  to  be  sharp.  This  instrument  will  often  cut  out 
fissures  as  well  as  the  original  bur.  It  can  be  ground  in  this  way 
until  the  blades  are  all  ground  off.  (Fig.  147.) 
The  old  inverted  cone  may  be  ground  into 
wedge  or  hatchet  shape  at  the  end  (Fig.  148) 
and  used  to  open  up  fissures,  but  such  an  in- 
strument unless  small  gives  the  tooth  quite  a 
shock.  It  cuts  better  if  the  hand-piece  is  given 
a  swaying  motion. 

SHARPENING  OF  INSTRUMENTS. 

No  instrument  which  is  intended  to  cut 
sensitive  dentin  should  be  used  until  it  is  first 
sharpened.  Because  a  hatchet  is  new,  it  is  no 
guarantee  that  it  is  sharp  though  it  is  likely  to 
be.  An  Arkansas  stone,  on  account  of  being 
fine  and  hard,  is  the  most  suitable  for  sharpen 
ing  dental  cutting  instruments.  If  the  stone 
is  soft  the  fine  instrument  will  sink  into  it,  cutting  it  into  gutters,  or 
will  catch  and  spoil  the  cutting  edge.  The  stone  should  be  wiped  off 
with  an  oiled  rag  and  thus  kept  free  from  particles  of  steel.  After 
spoon  excavators  have  been  sharpened  for  some  time  on  the  Arkansas 
stone  they  develop  what  is  called  a  thick  edge  and  should  be  ground 
thin  on  a  carborundum  wheel,  care  being  taken  not  to  heat  so  fine  a 
point  while  grinding  it. 

The  first  attempts  at  sharpening  chisels  and  hatchets  may  result 
in  improper  bevels,  but  some  attention  to  this  point  will  avoid  the  difl&- 
culty.  A  free  back  and  forth  movement  of  the  hand  will  ensure  best 
results.     Spoons  are  the  most  difficult  to  sharpen.     The  motion  should 


Figs.  146.     147.        148. 


PREPARATION    OF    PIT   AND   FISSURE    CAVITIES.  187 

be  back  and  forth  on  the  stone,  keeping  the  cutting  edge  parallel  with 
the  motion,  and  during  each  stroke  the  instrument  is  rotated  so  that 
every  part  of  the  edge  will  come  against  the  stone  during  the  motion. 

PREPARATION  OF  PIT  AND  FISSURE  CAVITIES. 

General  Conditions. — Pit  and  fissure  cavities  are  the  result  of 
defects  in  the  enamel  covering  of  the  tooth,  and  are  to  be  found  in  the 
occlusal  surfaces  of  bicuspids  and  molars,  lingual  surfaces  of  incisors 
and  occasionally  in  the  occlusal  third  of  the  buccal  surfaces  of  molars. 
The  enamel  begins  to  calcify  at  several  points,  the  central  incisor 
at  three  points,  the  bicuspids  and  molars  at  the  tips  of  the  cusps.  As 
the  calcific  matter  is  deposited  the  different  lobes  of  enamel  should 
join  between  the  cusps,  but  this  does  not  always  happen,  and  as  a  con- 
sequence there  is  left  a  fissure  which  is  a  defect  in  the  continuity  of 
the  surface  and  must  be  distinguished  from  a  groove  which  is  only  a 
depression  and  not  a  defect.  In  teeth  with  very  high  cusps  the  fissures 
are  often  quite  wide  open.  In  fact  they  are  sometimes  so  open  in 
lower  first  molars  that  a  fine  exploror  can  be  forced  between  the  plates 
at  almost  any  position  along  the  depression  between  the  cusps.  It 
is  a  peculiar  thing  that  often  even  such  a  wide  fissure  will  not  be  the 
seat  of  caries  while  others  of  less  width  will  decay.  But  the  great  major- 
ity of  all  fissures  are  the  seat  of  caries  sooner  or  later.  The  conditions 
are  the  most  favorable  for  development  of  micro-organisms.  Suitable 
material  to  develop  upon  is  squeezed  into  these  crevices  during  a  meal 
and  remains  there  only  to  be  supplemented  at  intervals.  If  it  were 
not  for  the  pits  and  fissures  in  teeth  caries  would  rarely  occur  in  occlusal 
surfaces,  because  they  would  be  kept  clean  by  the  mastication  of  food. 
There  is  no  better  cleaner  of  the  surfaces  of  the  teeth  than  the  chewing 
of  hard  tough  foods. 

Decay  in  pits  and  fissures  is  so  often  of  a  penetrating  character  that 
great  care  in  examination  is  necessary.  Even  though  a  fine  explorer 
will  not  enter  between  the  plates  of  enamel  there  may  be  a  large  cavity 
beneath.  In  fact  pulps  are  often  reached  by  decay  and  pain  be  the 
first  evidence  that  anything  is  wrong  without  any  perceptible  break 
in  the  enamel.  In  such  cases  a  close  observation  will  reveal  a  whitened 
area  beneath  the  enamel  along  the  fissure.  Any  change  in  the  color 
of  the  enamel  usually  indicates  some  defect  in  the  dentin  beneath. 
If  decay  has  once  begun  in  a  fissure  there  is  only  one  treatment  open 
to  the  operator.  Cut  it  out  in  its  entirety  and  include  it  in  the  cavity. 
Occasionally  fissures  may  be  found  in  recently  erupted  molars  which 
have  not  begun  to  decay  and  may  be  prevented  from  doing  so  by  drying 


l88  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

them  perfectly  and  squeezing  them  full  of  soft  cement  carried  to  place 
on  the  index  finger  and  held  there  until  the  cement  hardens.  This 
treatment  will  often  prevent  such  fissures  from  decaying  in  young 
patients  where  no  other  measures  are  available. 

If  every  operator  had  the  opportunity  of  seeing  the  micro-organisms 
of  decay  under  a  microscope  and  then  seeing  the  width  of  the  finest 
fissure  under  the  same  power  there  would  be  no  doubt  in  his  mind  as 
to  what  should  be  done.  Fissures  are  defects  and  are  always  a  source 
of  weakness  and  especially  so  when  radiating  from  a  cavity.  Decay 
having  once  occurred  in  a  fissure  is  an  indication  that  it  is  susceptible, 
and  even  if  the  decay  be  all  removed  recurrence  is  almost  certain  if 
the  fissures  are  not  cut  out  to  the  end  and  included  in  the  cavity. 
Besides  cutting  out  the  fissures  it  is  necessary  to  cut  out  angular  grooves 
because  it  is  impossible  to  properly  finish  a  filling  flush  with  the  margin 
in  these  deep  V-shaped  spaces.  If  they  are  left  they  only  form  places 
for  the  lodgment  of  fruit  seeds,  etc. 

Technique. — The  first  step  in  the  preparation  of  pit  cavities  such 
as  are  found  on  the  buccal  surfaces  of  the  first  molars  and  the  lingual 
surfaces  of  the  upper  incisors  is  to  get  access  to  the  cavity.  Since 
these  cavities  do  not  need  their  outlines  increased  to  prevent  further  de- 
cay their  preparation  is  quite  simple.  If  the  decay  has  not  progressed 
to  any  extent  they  may  be  opened  with  a  drill  or  a  cone  bur.  Once 
a  small  bur  will  enter  it  is  well  to  cut  outwards  rather  than  from  with- 
out inwards.  A  larger  and  larger  bur  is  used  until  free  access  is  gained 
to  the  cavity.  Usually  there  is  not  much  soft  decay  in  the  cavity  now 
under  consideration  so  the  inverted  cone  bur  may  be  used  to  complete 
the  preparation  of  the  cavity.  But  if  the  pit  has  been  the  starting 
point  of  quite  a  large  cavity  the  enamel  can  best  be  cut  away  with  a 
chisel,  the  softened  decay  removed  with  spoon  excavators  and  the 
cavity  washed  out  with  a  stream  of  tepid  water.  If  the  rubber  dam 
be  now  applied  a  full  view  of  the  cavity  is  possible  and  a  decision 
as  to  the  location  of  the  outline  arrived  at.  The  enamel  walls  may 
be  cut  back  with  a  good  sized  fissure  bur,  and  the  remainder  of  the 
decay  removed  with  spoon  excavators  and  a  cement  base  inserted 
which  will  become  the  axial  wall  of  the  cavity.  As  the  enamel  rods 
around  such  cavities  tend  to  lean  towards  the  pit  no  bevel  is  required 
if  the  walls  of  the  cavity  are  cut  at  right  angles  to  the  general  plane  of 
the  enamel  surrounding  the  cavity. 

Occasionally  a  cavity  in  the  lingual  surface  of  the  upper  central 
or  lateral  may  have  a  fissure  extending  frorn  it  quite  through  the  singu- 
ium  which  complicates   its  preparation.     The   fissure   usually  runs 


PREPARATION    OF    PIT    AND    FISSURE    CAVITIES.  189 

clear  to  the  limits  of  the  enamel  which  in  a  young  patient  will  be  far 
under  the  gum.  Such  fissures  must  be  cut  out  and  included  in  the 
cavity.  It  may  be  necessary  to  pack  the  gum  out  of  the  way  with 
gutta-percha.  An  inverted  cone  bur  will  cut  out  such  a  fissure  more 
rapidly  than  any  other  instrument.     Size  ^  to  f  mm. 

A  groove  often  extends  occlusally  from  a  pit  cavity  in  the  buccal 
surface  of  a  molar  but  rarely  needs  to  be  extended  over  the  ridge. 
If  an  occlusal  cavity  also  exists  it  should  be  prepared  before  the  buccal 
cavity  is  filled  because  when  the  two  cavities  are  open  at  the  same  time 
a  better  judgment  can  be  formed  as  to  whether  they  should  be  joined 
or  not. 

The  order  of  procedure  in  preparing  fissure  and  pit  cavities  in  the 
occlusal  surfaces  of  bicuspids  and  molars  is  dependent  upon  the 
extent  of  the  decay.  If  a  shallow  cavity  has  occurred  in  the  central 
fossa  of  a  molar  w^hich  has  fissures  radiating  from  it  the  edges  of  un- 
supported enamel  may  be  broken  down  with  a  chisel  and  the  outline 
form  proceeded  with  at  once.  The  fissures  can  be  cut  out  with  small 
inverted  cone  burs  or  those  made  into  drills  as  described  in  a  previous 
section.  Once  a  small  channel  has  been  cut  through  a  fissure  the 
edges  may  be  then  broken  down  with  a  sharp  chisel  until  the  general 
outline  has  been  obtained.  An  inverted  cone  bur  or  a  sharp  flat-ended 
fissure  bur  will  cut  out  a  flat  seat  and  give  the  walls  the  proper  form. 
If  the  cavity  walls  do  not  come  close  to  the  cusps  the  enamel  wall  needs 
no  bevel.  All  that  is  necessary  is  to  cut  the  walls  at  right  angles  to 
the  pulpal  wall.  If  there  is  now  any  decay  left  it  may  be  removed 
with  spoon  excavators.  If  the  pulpal  wall  has  been  cut  with  an  inverted 
cone  bur  it  will  not  be  necessary  to  cut  convenience  angles  nor  will  it 
be  necessary  to  provide  for  any  further  retention  than  that  cut  with  the 
inverted  cone  bur  in  forming  the  seat  and  walls.  Clear  the  cavity  of 
cuttings  and  it  is  ready  to  fill. 

If  a  deep  cavity  has  occurred,  however,  the  operator  is  concerned  with 
the  possibility  of  the  involvement  of  the  pulp  and  the  sensitiveness 
of  the  tissues  from  both  decay  and  exposure  to  changes  of  temperature. 
It  is  necessary  to  determine  the  condition  of  the  pulp  as  soon  as  possible 
because  if  it  must  be  devitalized  it  should  be  done  before  there  is 
any  cutting  of  sensitive  dentin  in  gaining  the  outline  form.  Cut 
away  the  unsupported  enamel  with  a  chisel,  putting  the  guard  finger 
on  the  tooth  to  be  cut.  Then  remove  the  softened  tissue  with  large 
spoon  excavators,  having  a  care  for  pressure.  The  spoon  may  be  worked 
under  the  leathery  decay  at  the  edges  and  flake  after  flake  removed 
without  pain.     Then  wash  out  with  tepid  water.     As  soon  as  it  is 


190 


PREPARATION    OF    CAVITIES    FOR    FILLINGS. 


determined  that  the  pulp  is  not  to  be  devitalized  there  are  two  methods 
open,  one  is  to  now  flood  the  remaining  decay  in  the  cavity  with  an 
anodyne  which  will  prevent  any  pain  from  exposure  and  proceed  with  the 
outline  form.  Then  remove  the  remaining  decay  and  cover  the  pulpal 
wall  with  cement.  In  this  method  the  deep  sensitive  tissues  are  not  ex- 
posed for  any  length  of  time.  The  other  method  is  to  immediately 
deal  with  the  deep  parts  of  the  cavity  covering  with  cement  and  as  soon 
as  this  hardens  proceed  with  the  outline  form.  By  the  latter  method 
the  sensitive  tissues  are  dealt  with  early  in  the  operation  and  are  pro- 
tected from  thermal  changes  and  the  seat  for  the  filling  may  be  cut  in 
the  cement  while  the  fissures  are  being  drilled  out.  There  is  always 
a  chance  of  finding  some  decay  under  the  edge  of  the  cement  when  the 
fissures  are  cut  out.  The  final  step  in  either  method  is  to  bevel  the 
enamel  walls  which  may  be  done  with  a  round  bur  run  rapidly  or  a 
fissure  bur  in  the  right  angle  held  perpendicular  to  the  pulpal  wall  and 
then  in  such  locations  as  come  close  to  the  cusps  the  instrument  should 
be  held  so  as  to  give  the  wall  a  slight  bevel. 

A  cavity  in  either  of  the  occlusal  pits  of  the  upper  bicuspids  should 


Fig.  149 


Fig.  150. 


Fig.  i:;i. 


Fig   152. 


Fig.  153. 


when  completed  include  both  pits  and  the  connecting  fissure  or  groove. 
It  is  very  rare  indeed  that  the  tissue  between  these  pits  should  be  left 
if  either  have  failed.  It  is  not  necessary  to  cut  this  fissure  or  groove 
more  than  one  to  one  and  a  half  mm.  in  width  (Fig.  149).  Cavities 
in  the  occlusal  surface  of  the  lower  bicuspids  need  not  be  treated  in  the 
same  way.  In  the  majority  of  cases  there  is  neither  a  fissure  nor  a 
groove  joining  the  pits  but  a  ridge  of  sound  enamel,  which  should  be 
rarely  cut  across  because  defects  have  occurred  in  either  or  both  pits, 
unless,  of  course,  the  enamel  has  been  undermined  by  caries.  (Fig.  1 50.) 
There  is  a  crescentic  form  of  the  lower  second  bicuspid  which  if  de- 
fective at  all  should  be  cut  out  in  its  entirety.     (Fig.  151). 

Occlusal  cavities  in  the  pits  and  fissures  of  the  upper  molars  depend 
in  their  outline  form  entirely  upon  the  extent  and  direction  of  the  fissures 
and  angular  grooves.  A  cavity  in  the  central  fossa  of  the  upper  first  or 
second  molar  is  usually  simple  in  preparation.  There  is  often  a  ques- 
tion, however,  as  to  how  far  to  cut  out  grooves  extending  to  the  mesial 


SMOOTH    SURFACE    CAVITIES. 


191 


or  to  the  buccal.  The  general  rule  applies,  cut  all  fissures  and  grooves 
until  a  good  finishing  margin  can  be  obtained.  Often  it  is  advisable 
to  cut  the  buccal  groove  out  until  the  break  is  reached  to  form  the  buccal 
surface.  In  such  cases  the  extremity  of  the  groove  should  be  sloped 
into  the  center  of  the  cavity  giving  a  decided  bevel  to  the  wall.  Thus 
a  good  finishing  margin  is  reached  without  cutting  a  slot  clear  through 
to  the  buccal  surface  which  would  tend  to  weaken  the  cusps.'''  Where 
there  is  a  defect  in  both  the  central  fossa  and  the  disto-lingual  groove 
it  is  always  advisable  to  prepare  both  cavities  at  the  same  time  when  a 
decision  can  be  made  as  to  the  advisability  of  cutting  across  the  trans- 
verse ridge.  If  cut  across  it  should  appear  as  Fig.  152.  If  there  is  any 
thickness  of  dentin  under  the  ridge  it  should  not  be  cut  across.  (Fig. 
153.)  There  is  often  a  supplemental  cusp  in  the  upper  first  molar 
which  has  grooves  and  fissures  about  it  which  must  be  cut  out.  These 
are  often  so  penetrating  that  cusps  are  undermined  and  must  be  cut 
away  thus  facing  almost  the  whole  occlusal  surface  with  the  filling. 
(Fig.  154.) 


Fig.  154. 


Fig.  155. 


Fig.  1^6. 


Fig.  157. 


Third  molars  are  irregular  in  their  markings  but  usually  have  three 
cusps,  two  buccal  and  one  lingual,  with  a  pit  between  and  fissures  run- 
ning buccally,  mesio-lingually  and  disto-lingually.  Neither  fissures 
nor  grooves  pass  over  the  marginal  ridges.     (Fig.  155.) 

Lower  first  molars  have  a  central  depression  which  is  often  defective 
and  fissures  and  grooves  extending  buccally,  lingually,  mesially,  and 
distally.  These  cavities  are  the  most  uniform  of  any  under  this  head- 
ing.    (Fig.  156.) 

The  lower  third  molars  often  have  the  same  outline  as  the  lower 
first,  while  the  second  will  have  the  appearance  of  Fig.  157. 

SMOOTH  SURFACE  CAVITIES. 

I.  Cavities  in  the  gingival  third  of  labial,  buccal  and  lingual 
surfaces. 

General  Considerations. — The  number  of  cavities  and  the  extent 
of  caries  in  these  locations  is  a  true  index  to  the  care  of  the  teeth.  Cavi- 
ties should  not  occur  in  these  locations  if  our  present  views  of  the 


192  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

cause  of  caries  be  correct,  that  is  if  the  patient  takes  reasonable 
care  of  his  teeth.  There  is  not  a  buccal  or  lingual  surface  except  in 
cases  of  marked  irregularity  that  cannot  be  reached  with  a  tooth  brush. 
It  is  safe  to  say  to  the  patient  who  has  such  cavities  that  he  does  not 
brush  his  teeth  properly  and  a  lesson  should  be  given  to  him  at  once. 
In  the  majority  of  these  cases  the  first  indication  of  beginning  caries 
is  a  sensitive  spot  that  the  patient  accidentally  finds  with  his  finger  nail 
or  a  tooth  pick.  The  area  of  the  sensitiveness  gradually  increases 
until  the  tooth  brush  is  not  used  even  on  that  side  of  the  mouth  for 
fear  of  touching  the  sensitive  spot.  A  break  in  the  enamel  occurs  and 
extends  both  mesially  and  distally.  This  line  is  just  at  the  junction 
of  the  free  margin  of  the  gum  with  the  enamel  where  there  is  a  slight 
protection  from  the  action  of  the  lips.  These  white  lines  of  superficial 
decay  rarely  enter  the  proximal  surface  in  young  patients  but  usually 
do  so  in  those  of  advanced  years  where  the  gums  have  receded  to 
some  extent.  This  decay  never  begins  under  the  free  margin  of  the 
gums  but  often  extends  there  by  undermining  the  enamel.  In  such 
cases  the  sharp  edge  of  the  cavity  irritates  the  gum  tissue,  causing  a 
hypertrophy  which  makes  it  appear  as  if  caries  had  begun  under  the 
gum. 

The  proper  treatment  of  labial,  buccal,  and  lingual  caries  calls  for 
careful  consideration,  not  that  fillings  are  often  dislodged  but  that  they 
so  often  fail  at  the  margins.  There  is  usually  an  area  of  defective 
enamel  extending  from  the  cavity  and  unless  this  is  all  cut  out  failure 
is  certain  and  even  then  the  operation  has  not  changed  the  environ- 
ment. The  future  of  fillings  in  these  locations  depends  more  upon  the 
patient  than  upon  the  perfection  of  the  operation.  If  after  these  loca- 
tions on  the  teeth  have  been  made  comfortable  the  patient  cannot  be 
induced  to  regularly  and  carefully  clean  them  no  kind  of  operation 
other  than  the  removal  of  the  gingival  third  of  the  affected  surface  and 
covering  the  gingival  margin  with  healthy  gum  tissue  will  last  even  a 
reasonable  time.  It  is  often  a  serious  question  how  much  of  the  enamel 
about  such  defects  should  be  cut  out  and  included  in  the  cavity.  The 
indication  of  the  beginning  of  caries  is  a  sensitive  area.  In  such  cases 
a  thorough  polishing  with  powdered  pumice  followed  by  chalk,  with 
instructions  to  the  patient  to  follow  a  simular  treatment  will  often 
prevent  the  formation  of  a  cavity.  Since  the  general  introduction  of 
porcelain  as  a  filling  material  labial  cavities  may  be  more  freely  cut 
for  the  prevention  of  future  caries. 

Though  many  labial,  buccal  and  lingual  cavities  are  difficult  to 
manage  there  are  a  few  where  decay  is  slow  and  the  tissue  so  non-sen- 


SMOOTH    SURFACE    CAVITIES.  1 93 

sitive  that  they  are  among  the  simplest  operations  that  come  under  the 
dentist's  care. 

Technique. — The  form  to  be  given  these  cavities  is  simple  but 
the  management  of  the  operation  is  exceptionally  difficult,  be- 
cause of  the  hypersensitiveness  of  the  dentin  and  even  the  enamel, 
and  because  of  the  difficulty  of  getting  free  access  to  the  cavity.  The 
gum  tissue  has  usually  grown  into  the  cavity  and  is  exceptionally  sen- 
sitive as  all  pathological  gum  tissue  is.  And  perhaps  the  greatest 
handicap  of  all  is,  the  patient  dreads  the  operation  more  than  all  others 
and  the  operator  dreads  it  himself.  Operations  in  these  locations 
have  a  peculiar  tendency  to  increase  the  flow  of  saliva  which  adds 
materially  to  the  difficulty  of  the  operation  and  to  the  discomfort  of  the 
patient.  There  are  few  operations  in  dentistry  where  the  pain  and 
discomfort  to  the  patient  are  so  out  of  control  of  the  operator  as  a 
shallow  sensitive  cavity  in  the  buccal  surface  of  a  lower  molar  in  a 
nervous  woman.  The  saliva  flows  freely,  the  ordinary  therapeutic 
remedies  cannot  be  used  unless  the  rubber  is  applied  and  this  cannot 
be  done  without  a  clamp  which  will  certainly  touch  the  sensitive  area. 
Difficulties  such  as  these  can  only  be  overcome  by  an  experienced  mas- 
ter hand.  The  hypodermic  injection  of  novocain  and  adrenalin 
chloride  into  the  gum  opposite  the  end  of  the  root  promises  results, 
while  the  injection  of  cocaine  into  the  tooth  with  the  high  pressure 
syringe  is  more  to  be  depended  upon. 

In  the  majority  of  small  cavities  even  if  the  gum  tissue  has  grown 
into  them  it  is  less  painful  and  more  expeditious  not  to  make  any  at- 
tempt to  remove  the  gum  from  the  cavity  until  the  operation  can 
be  made,  while  in  large  and  deep  cavities  where  cotton  and  gutta- 
percha can  be  packed  and  retained  without  the  removal  of  much  of  the 
decay  it  is  wise  to  do  so  at  a  previous  sitting.  When  the  gum  is  re- 
moved from  these  deep  cavities  one  of  the  difficulties  has  been  over- 
come. In  labial  cavities  the  first  step  after  using  a  solution  of  cocaine 
on  the  gum  around  the  neck  of  the  tooth  is  to  apply  the  rubber  dam. 
Dry  the  cavity.  Break  down  the  enamel  around  the  cavity  avoiding  the 
decalcified  dentin.  Carefully  plan  the  next  step  which  will  be  the  most 
important  in  the  preparation  of  all  such  cavities.  It  is  just  as  painful 
to  remove  one  layer  of  the  decalcified  tissue  as  it  is  to  remove  the  whole 
mass.  If  the  cavity  be  small  and  no  danger  of  pressing  upon  the  pulp, 
select  a  location  at  the  mesial  or  distal  wall  and  sink  a  sharp  hatchet 
or  Darby-Perry  spoon  No.  9  or  10  down  to  the  bottom  of  the  decay 
and  scoop  the  whole  mass  out  at  once.  Just  as  this  cut  is  undertaken 
the  operator  should  warn  his  patient  and  at  the  same  time  divert  his 
13 


194  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

attention  by  remarks  on  some  interesting  topic.  An  application  of 
hot  phenol  or  phenol  and  alcohol  will  relieve  the  pain  incident  to  the 
exposure  of  the  dentin  to  the  air.  The  further  preparation  of  the  cav- 
ity will  not  be  more  sensitive  than  any  other  unless  it  should  reach  the 
junction  of  the  proximal  surface  with  the  labial  about  one  mm.  from 
the  gum.  An  inverted  cone  bur  in  the  direct  hand-piece  will  cut  a  flat 
axial  wall,  and  extend  the  other  walls  in  any  direction  leaving  sufficient 
undercut  to  start  and  retain  the  filling.  Since  the  introduction  of  por- 
celain it  is  not  necessary  to  discuss  the  peculiar  forms  of  these  cavities 
which  make  gold  fillings  the  least  conspicuous.  The  outline  should 
extend  under  the  free  margin  of  the  gum  and  when  finished  be  covered 
with  it.  There  should  be  such  extension  mesially  and  distally  as  will 
ensure  sound,  hard  enamel.  If  any  special  convenience  is  required  to 
start  a  gold  filling  it  should  be  cut  in  that  part  of  the  cavity  furthest 
from  the  operator  and  in  the  greatest  thickness  of  dentin.  Any  un- 
dercuts in  the  dentin  for  retentive  purposes 
should  be  in  opposite  walls  of  the  cavity.  The 
cavo-surface  angle  may  be  trimmed  with  a 
chisel  or  a  round  bur  or  a  cone  bur.  The  r-e- 
maining  decay  over  the  axial  wall,  if  any, 
Fig  I  8  Fig"  159.  should  be  removed  and  the  cavity  is  pre- 
pared for  filling.  (Figs.  158  and  159.) 
Buccal  cavities  in  bicuspids  are  treated  in  like  manners  but  those 
in  molars  are  modified  by  the  difficulty  of  access  and  the  impossibility 
of  applying  the  rubber  dam  when  the  gingival  wall  is  far  below  the 
gum.  The  decay  may  be  removed  in  the  same  way  and  the  final 
forming  of  the  cavity  done  with  a  bur  in  the  right  angle.  There  is 
one  frequently  occurring  buccal  cavity  which  nearly  always  fails  when 
filled.  It  occurs  in  the  distal  third  of  the  buccal  surfaces  of  third 
molars.  These  surfaces  are  rarely  cleaned  by  either  food  or  the  tooth 
brush.  Sooner  or  later  they  involve  the  whole  disto-buccal  surface 
and  the  occlusal.  While  they  are  small  cavities  in  the  buccal  surface 
they  are  so  sensitive  and  difficult  of  access  that  proper  extension  cannot 
be  made,  hence  recurrence  of  caries  is  inevitable.  As  soon  as  the 
occlusal  surface  is  involved  a  good  dovetail  can  be  cut  and  the  filling 
when  inserted  sloped  off  in  such  a  manner  as  to  prevent  heavy  occlu- 
sion upon  it. 

Lingual  cavities  in  the  gingival  third  are  rare.  They  only  occur 
because  of  a  marked  recession  of  the  gums  or  from  wearing  an  artificial 
denture.  The  preparation  of  the  cavity  is  similar  to  that  in  the  labial 
and  buccal  surfaces.  Any  variation  will  depend  upon  the  extent  and 
location  of  the  caries. 


SMOOTH    SURFACE    CAVITIES.  I95 

2.  The  preparation  0}  cavities  in  proximal  surfaces  0}  incisors 
and  cuspids  which  do  not  involve  the  incisal  angle. 

General  Considerations. — Patients  who  have  neglected  their 
teeth  for  years  take  an  anxious  interest  in  them  as  soon  as  cavities 
appear  in  their  incisors  and  cuspids.  They  recognize  at  once  that 
if  these  teeth  become  unsightly  they  have  lost  one  mark  of  beauty. 
They  often  allow  molars  and  bicuspids  to  decay  beyond  any  hope  of 
being  restored  to  usefulness  under  the  foolish  notion  that  they  can  re- 
tain the  anterior  teeth  even  if  the  others  are  lost.  There  is  no  more 
fallacious  notion  than  this  met  with  in  the  practice  of  dentistry,  except 
perhaps  mistaking  the  first  permanent  molar  for  a  deciduous  tooth. 
It  is  dijQ&cult  to  decide  what  is  best  to  do  for  a  patient  of  say  twenty- 
eight  years  of  age  who  has  lost  the  power  of  mastication  on  his  molars 
and  bicuspids  and  has  several  proximal  cavities  in  the  incisors.  The 
incisors  are  used  for  a  purpose  for  which  they  were  never  intended, 
and  as  a  consequence  wear  down  rapidly,  cutting  off  the  incisal  reten- 
tion to  proximal  fillings.  While  it  is  true  that  a  patient  is  justified  in 
becoming  anxious  when  his  anterior  teeth  begin  to  decay  he  should  in 
fact  be  more  anxious  when  his  molars  and  bicuspids  show  signs  of 
being  lost,  because  the  anterior  teeth  cannot  be  preserved  permanently 
if  they  are  used  for  the  mastication  of  food.  Artificial  dentures  of 
molars  and  bicuspids  alone  are  but  a  poor  substitute  for  the  natural 
teeth  of  mastication.  The  incisors  will  be  used  in  preference,  to  their 
destruction.  It  is  the  dentist's  duty  when  he  sees  small  proximal 
cavities  in  the  anterior  teeth  to  look  into  the  future  sufficiently  to  edu- 
cate his  patient  along  the  lines  of  being  exceedingly  anxious  about  the 
condition  of  the  molars  and  bicuspids.  Fillings  in  the  anterior  teeth 
even  if  small  are  doomed  if  they  are  called  upon  to  bear  the  stress  of 
mastication.  These  teeth  are  thin  and  small  and  give  but  a  poor  oppor- 
tunity for  the  firm  anchorage  of  fillings  and  if  called  upon  to  do  a  duty 
they  were  not  intended  for  there  is  certain  to  be  failure.  This  is  the 
cause  of  a  large  class  of  failures  in  fillings  in  the  anterior  teeth  which 
cannot  be  classed  among  failures  from  recurrence  of  caries. 

It  has  been  found  by  those  of  largest  experience  in  filling  teeth  that 
there  are  certain  areas  of  the  teeth  more  susceptible  to  caries  than 
others.  These  susceptible  areas  are  found  to  be  those  which  are  not 
habitually  cleaned  by  excursions  of  food  in  mastication,  or  by  the  friction 
of  the  cheeks,  lips,  or  tongue.  Proximal  surfaces  of  the  anterior  teeth 
which  are  close  together  are  not  habitually  clean,  and  decay  in  propor- 
tion to  their  uncleanness.  It  has  also  been  observed  that  not  all  points 
of  proximal  surfaces  are  equally  susceptible.     All  that  portion  from  the 


196  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

incisal  edge  to  the  contact  point  is  usually  immune  and  in  fact  the 
actual  contact  point  is  rarely  the  scat  of  beginning  caries  but  a  point 
immediately  gingival  to  the  contact  is  the  susceptible  area.  This  is 
as  it  were  an  eddy  behind  the  contact  where  secretions  may  rest  and 
plaques  form  without  disturbance.  Each  case  presents  its  own  little 
variations  and  should  be  considered  before  any  operating  is  proceeded 
with,  because  in  these  days  of  esthetics  the  whole  susceptible  area  may 
sometimes  be  removed  and  restored  with  gold  without  exposing  the  filling. 
It  has  been  noticed  for  a  long  time  that  proximal  gold  fillings  fail 
at  the  gingival  margin,  which  is  true,  but  closer  observation  has  shown 
that  failure  rarely  occurs  in  the  center  of  the  proximal  surface  but  at 
the  linguo-gingival  angle  and  the  labio-gingival  angle.  That  portion 
of  the  gingival  margin  in  the  center  is  usually  covered  with  gum  tissue 
and  hence  does  not  decay,  while  both  to  the  lingual  and  to  the  labial  of 
this  point  the  free  margin  of  the  gum  crosses  the  margin  of  the  filling 
and  at  these  points  recurrence  happens.  If  the  margin  is  placed  im- 
mediately gingival  to  the  contact  it  is  in  a  susceptible  area  and  failure 
is  imminent.  Teeth  which  are  spaced  in  the  occlusal  or  incisal  third 
will  have  their  proximal  surfaces  cleaned  by  the  excursions  of  food  down 
to  the  contact  and  if  the  margin  of  the  filling  is  incisal  to  the  contact  re- 
currence is  unlikely. 

The  lingual  margin  is  often  a  location  of  failure  of  proximal  gold 
fillings  in  the  anterior  teeth.  Operators  have  too  frequently  left  the 
lingual  enamel  plate  for  the  convenience  of  packing  the  gold.  Cavities 
are  often  cut  quite  over  on  the  labial  surface  for  convenience  of  access. 
Such  preparations  are  a  mark  of  the  man  who  is  compelled  to  do  too 
many  fillings  a  day  to  make  a  competence.  There  is  often  a  marked 
concavity  both  inciso-gingivally  and  mesio-distally  on  the  lingual  sur- 
face of  an  incisor  which  leaves  the  lingual  wall  little  more  than  enamel 
if  a  proximal  cavity  occurs.  If  such  a  lingual  plate  of  enamel  is  left  it 
is  not  strong  enough  to  bear  the  stress  of  packing  gold  against  it  without 
fracture.  Even  if  this  enamel  plate  does  not  actually  break  out  during 
the  insertion  of  the  gold  it  becomes  checked  sufficiently  to  allow  leakage. 
There  is  only  one  safe  rule  to  follow.  Cut  the  enamel  away  on  the 
lingual,  until  what  remains  is  supported  by  dentin. 

The  preparation  of  small  proximal  cavities  in  the  anterior  teeth 
naturally  divides  itself  into  two  general  classes.  Those  which  are  pre- 
pared with  a  view  to  the  permanency  of  the  filling  and  those  which  are 
prepared  knowing  that  the  filling  will  be  more  or  less  temporary.  If 
all  the  work  of  the  dentist  could  be  made  mechanically  correct  and  its 
permanency  was  not  dependent  upon  conditions  outside  of  his  control, 


SMOOTH    SURFACE    CAVITIES.  I97 

dentistry  would  be  practised  as  a  trade  and  would  not  have  the  power 
to  retain  so  many  bright  minds  within  its  ranks.  The  varying  circum- 
stances that  influence  the  permanency  of  dental  operations  make  dentis- 
try interesting.  The  only  man  who  can  say  that  his  operations  will  be 
permanent  is  the  one  who  does  not  know  or  the  one  who  intentionally 
wishes  to  deceive.  The  claim  of  absolute  permanency  of  dental  opera- 
tions has  done  much  to  discredit  the  profession  because  the  patient 
who  has  lost  several  so-called  permanent  fillings  must  think  that  the 
dentist  was  ignorant  or  dishonest,  either  of  which  is  not  creditable  to 
the  profession.  Therefore  when  we  speak  of  preparations  for  so-called 
permanent  fillings  w^e  mean  only  relatively  permanent. 

Porcelain  fillings  have  within  the  past  few  years  taken  such  a  hold 
on  the  profession  that  few  gold  fillings  are  now  inserted  in  exposed  sur- 
faces of  the  anterior  teeth  for  patients  who  value  their  personal  ap- 
pearance. Though  this  may  be  true  there  is  still  a  large  field  left  for 
gold  and  other  fillings. 

The  preparation  of  cavities  for  those  fillings  which  may  be  looked 
upon  as  more  or  less  permanent  demands  a  study  of  the  general  con- 
dition of  the  patient,  the  oral  secretions,  the  mucous  membranes  and 
the  teeth.  There  must  be  a  careful  study  of  the  susceptible  and  im- 
mune areas  of  the  teeth.  These  considerations  will  usually  demand 
the  extending  of  the  gingival  wall  of  proximal  cavities  under  the  free 
margin  of  the  gum  and  the  labial  and  lingual  w^alls  to  those  areas 
which  are  immune  to  caries,  while  the  incisal  margin  will  be  carried 
far  enough  to  the  incisal  to  prevent  it  from  coming  in  contact  with  the 
adjoining  tooth.  If  a  cavity  is  so  extended  there  will  be  no  portion  of 
its  margin  in  susceptible  areas.  The  gingival  margin  will  be  covered  by 
healthy  gum  tissue,  the  labial  margin  will  always  be  kept  clean  by 
foods,  the  lips,  and  the  brush,  the  lingual  margin  by  food  and  the 
tongue,  and  the  incisal  margin  by  food.  The  only  other  requisites  for 
a  fairly  permanent  filling  will  be  perfect  mechanical  adaptation  to  the 
cavity  walls  and  not  so  much  stress  of  occlusion  as  will  wear,  stretch,  or 
dislodge  the  filling. 

The  preparation  of  cavities  in  proximal  surfaces  of  incisors  which 
must  of  necessity  be  looked  upon  as  temporary  demand  less  general 
consideration  but  more  consideration  of  the  particular  reasons  for 
such  temporary  operations.  There  must  be  a  perfect  understanding 
between  patient  and  operator  when  operations  are  to  be  made  which  are 
not  ideal.  The  ideal  operation  may  be  pointed  out  to  the  patient  and 
the  reasons  given  for  deviations  from  it.  In  this  way  the  patient 
understands  what  is  to  be  expected  from  such  operations  and  is  not 


198  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

deceived.  And  besides  if  the  operator  shows  himself  to  be  a  good  prog- 
nosticator  his  standing  is  enhanced  in  the  patient's  mind  and  not  di- 
minished if  the  operation  lasts  no  longer  than  he  said. 

While  we  must  admit  that  all  cavities  cannot  be  prepared  according 
to  an  ideal  formula  there  is  no  intention  in  this  chapter  to  countenance 
slip-shod  operating.  Every  reason  that  may  be  given  here  for  not  pre- 
paring cavities  according  to  the  outline  in  a  previous  paragraph  can 
be  made  an  excuse  for  careless  operating.  One  operator  may  be  so 
much  more  skillful  and  deft  about  his  work,  that  what  would  be  too 
painful  for  another  operator's  patient  to  bear  would  be  easily  borne  by 
his.  The  rough,  unskillful  operator  will  rarely  find  patients  who  can 
bear  to  have  proper  preparations  made  in  teeth  with  living  pulps, 
while  the  skillful  operator  will  rarely  find  cases  where  perfect  prepara- 
tions cannot  be  made. 

If  the  proper  preparation  of  a  cavity  would  prove  too  painful  for  a 
young  patient  a  temporary  operation  is  indicated,  and  in  such  a  case 
where  cement  is  to  be  used,  it  is  not  desirable  to  break  down  any  more 
of  the  enamel  than  will  ensure  sufficient  access  to  remove  the  decay. 
Then  again  if  small  proximal  cavities  develop  slowly  and  the  ex- 
posure of  gold  would  be  objectionable  it  would  be  manifestly  better  to 
gain  sufficient  space  to  insert  small  gold  fillings  than  make  the  ideal 
extensions.  Such  small  fillings  are  not  likely  to  prevent  further  decay 
for  more  than  three  or  four  years  but  the  patient  has  not  had  gold  fillings 
exposed  in  the  teeth  for  that  much  of  her  life.  While  it  is  sometimes 
desirable  to  make  cavities  that  do  not  have  their  margins  in  immune 
areas  there  are  certain  cases  which  are  so  markedly  susceptible  to 
caries  that  they  must  have  their  margins  carried  full  well  on  to  immune 
areas. 

Technique. — Separation  is  a  necessity  for  the  proper  preparation 
and  filling  of  proximal  cavities  in  the  incisors  and  cuspids.  Space 
should  be  gained  in  such  a  way  as  to  prevent  the  teeth  from  being  sore 
when  worked  upon.  There  is  no  necessity  for  having  the  peridental 
membrane  so  sensitive  that  the  patient  experiences  pain  from  every 
touch  of  the  tooth.  If  slight  soreness  should  occur  it  is  well  to  support 
the  teeth  while  operating. 

Usually  the  first  step  in  the  preparation  of  proximal  cavities  in 
incisors  is  to  chip  away  the  thin  enamel  with  a  chisel  or  a  hatchet  or 
hoe  excavator.  These  latter  instruments  are  narrow  in  the  blade 
and  unless  carefully  used  the  points  may  drop  into  the  sensitive  por- 
tions of  the  cavity.  The  thin  edges  of  the  cavity  may  be  shaved  down 
from  the  incisal  to  the  gingival  on  the  labial  and  the  lingual  with  the 


SMOOTH    SURFACE    CAVITIES.  1 99 

corner  of  a  triangular  chisel,  holding  the  second  finger  on  the  tooth  as  a 
guard.  The  blade  of  the  chisel  should  be  carried  toward  the  center  of 
the  tooth  as  the  edge  is  carried  toward  the  gingival.  A  sharp  spoon 
will  remove  the  major  portion  of  the  decay.  At  this  time  a  decision 
can  be  made  as  to  the  extent  of  the  carious  tissue  and  the  probable 
outline  form. 

The  outline  form  having  been  decided  upon,  the  chisel  with  a 
keen  edge  will  do  more  than  any  other  instrument.  The  enamel  may 
be  cut  away  chip  by  chip  until  the  incisal  margin  reaches  a  point  which 
will  be  kept  clean  by  excursions  of  food.  Both  the  labial  and  the  lin- 
gual walls  may  be  cut  back  with  the  chisel,  using  the  pen  grasp,  but 
occasionally  the  thumb  and  palm  grasp  will  reach  the  lingual  walls 
to  best  advantage.  In  opening  up  the  cavity  the  loose  decay  was  re- 
moved, also  the  thin  enamel  edges,  so  now  the  chief  concern  is  with  the 
proper  formation  of  the  cavity  for  the  reception  of  the  filling  and  the  pre- 
vention of  future  decay  without  regard  to  existing  caries.  Cavities 
of  less  than  1.5  mm.  in  diameter  without  much  undermining  of  the 
enamel  can  be  extended  to  advantage  with  a  round  bur.  The  largest 
round  bur  which  will  enter  the  cavity  is  not  so  likely  to  cut  into  the  dentin 
and  cause  pain.  The  blades  may  be  carried  against  the  enamel  cut- 
ting from  the  dentin  outwards.  It  will  be  found  necessary  to  extend 
the  gingival  wall  considerably  rootwards  in  many  cases  to  insure  the 
margin  of  the  cavity  being  covered  with  healthy  gum  tissue.  In  the 
case  of  the  small  cavity  just  mentioned  a  round  bur  directed  against  this 
wall  in  the  manner  described  will  work  quite  efficiently.  But  in  the 
majority  of  cases  an  inverted  cone  bur  h  mm.  in  diameter  for  laterals 
and  small  cavities,  and  i  mm.  in  diameter  for  centrals  directed 
against  the  gingival  wall  and  swept  across  from  labial  to  lingual  and 
from  Ungual  to  labial  holding  the  hand-piece  at  such  an  angle  as  will 
give  the  corner  of  the  bur  a  grip  of  the  tissue  will  usually  cut  the  dentin 
gingivally  and  at  the  same  time  make  a  flat  seat  for  the  filling  with 
convenience  angles  for  starting  the  gold  both  at  the  linguo-gingivo-axial 
angle  and  the  labio-gingivo-axial  angle.  As  the  bur  cuts  into  the  angles 
the  hand-piece  should  be  swayed  in  an  opposite  direction  and  the  bur 
carried  upward  along  the  labio-axial  line  angle  and  linguo-axial  line 
angle,  thus  making  a  slight  groove  which  should  under  no  cir- 
cumstances extend  more  than  one-third  or  one-quarter  of  the  distance 
to  the  incisal  retention.  In  this  connection  it  must  not  be  under- 
stood that  grooves  are  recommended  in  either  the  labial  or  lingual  walls. 
A  slight  extension  incisally  from  the  convenience  angles  for  holding  the 
filling  more  securely  during  its  insertion  is  all  that  is  desirable.     As 


200  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

the  gingival  wall  is  thus  formed  the  enamel  edge  will  not  be  cut  away 
which  can  be  done  with  a  narrow  chisel  introduced  from  the  labial. 
Such  a  chisel  should  have  a  fine  neck  so  it  may  be  held  at  any  angle. 
A  round  bur  may  be  used  to  trim  the  enamel  at  the  gingival  but  must 
be  held  firmly,  allowing  it  to  rotate  in  the  proper  direction,  or  it  may 
catch  on  the  edge  and  pull  the  rubber  off  or  cut  a  deep  notch  in  the 
margin.  The  outline  at  the  junction  of  the  lingual  wall  with  the 
gingival  and  the  labial  with  the  gingival  must  be  cut  with  great  care 
otherwise  too  much  bevel  will  occur,  or  these  points  will  not  be  ex- 
tended far  enough  to  ensure  a  clearing  margin.  It  must  be  kept  in 
mind  that  these  are  vulnerable  points  in  these  fillings. 

Any  decay  or  decalcified  tissue  that  might  be  remaining  in  the 
cavity  should  be  removed.  Spoon  excavators  with  thin  cutting  blades 
and  of  a  size  to  readily  enter  the  cavity  will  rapidly  remove  the  remain- 
ing defective  tissue.  Darby-Perry  No.  9,  10,  2  and  4  are  thin  bladed 
spoons  suitable  for  small  cavities. 

Give  the  cavity  proper  form  to  resist  any  stress  that  may  come 
upon  the  filling,  also  make  it  of  such  a  form  that  it  will  be  convenient  to 
fill.  In  cases  where  the  gingival  wall  does  not  need  extension  for  pre- 
vention, and  the  outline  form  has  been  obtained  and  the  decay  re- 
moved, the  resistance  form,  the  retentive  form  and  the  convenience 
form  may  be  all  made  at  the  same  time.  An  inverted  cone  bur  ^  mm.  in 
diameter  for  small  cavities  and  f  or  i  mm.  in  diameter  for  larger  cavi- 
ties in  centrals  and  cuspids  will  cut  a  flat  seat  at  the  gingival  by  holding 
the  instrument  parallel  with  the  long  axis  of  the  tooth  and  carrying  it 
well  into  the  linguo-gingivo-axial  angle  and  into  the  labio-gingivo- 
axial  angle  as  before  mentioned.  In  these  cavities  it  is  impossible  to 
cut  the  gingival  wall  at  right  angles  to  the  long  axis  of  the  tooth  with 
an  inverted  cone  bur  because  the  shaft  cannot  be  held  exactly  parallel 
with  the  long  axis,  but  if  the  dentin  be  cut  slightly  deeper  at  the  gingivo- 
axial  line  angle  the  outer  border  or  enamel  wall  may  then  be  trimmed 
sloping  inward  except  at  the  cavo-surface  angle  which  should  be 
beveled.  The  main  feature  of  the  gingival  wall  is  to  be  flat  from  labial 
to  lingual  and  form  a  right  angle  or  an  acute  angle  with  the  axial  wall. 
There  should  be  no  deep  grooving  of  the  gingival  wall  nor  cutting  of 
deep  pits.  A  flat  seat  with  walls  forming  right  angles  from  it  is  the  best 
form  to  resist  stress.  The  necessary  retentive  form  in  these  cavities  is 
provided  for  in  the  cut  into  the  linguo-gingivo-axial  angle  and  the  labio- 
gingivo-axial  angle  and  a  slight  cut  into  the  dentin  at  the  junction  of  the 
lingual  wall  with  the  labial  at  the  incisal  extremity  of  the  cavity.  At 
these  points  the  dentin  is  the  thickest  and  the  cuts  are  directed  away 


SMOOTH    SURFACE    CAVITIES. 


20I 


from  the  pulp.  The  incisal  retention  can  be  completed  with  an  acute 
angled  hatchet,  S,  S.  W.,  No.  27.  This  instrument  may  start  to  cut  at  the 
labio-axial  line  angle  about  a  milhmeter  from  the  incisal  retention  and 
be  carried  toward  the  incisal  and  then  started  again  in  a  similar  position 
on  the  lingual  carrying  each  cut  around  the  incisal  retention  started 
with  the  bur.  This  action  of  the  instrument  will  deepen  the  cavity 
rapidly.  It  is  not  necessary  to  make  a  deep  undercut  at  this  point,  it  is 
more  important  to  have  a  good  bulk  of  gold  even  at  right  angles  to  the 
axial  wall  than  a  fine  hole  bored  deeply.  The  lingual  wall  should 
not  under  any  circumstances  be  grooved  in  its  length  nor  should 
the  labial.  There  are  cases  where  a  short  groove  may  be  extended 
from  the  convenience  angles  but  even  these  are  not  necessary  in  small 
cavities. 

A  source  of  weakness  in  fillings  at  the  incisal  margin  is  the  thinness 
of  the  gold.  The  enamel  rods  on  distal  surfaces  have  a  decided  incline 
towards  the  incisal,  and  if  beveled  at  all  makes  the  gold  thin.     This 


Fig.  160. 


Fig.  161 


Fig.  162. 


Fig.  163. 


difficulty  may  be  overcome  if  the  incisal  retention  is  some  distance 
gingival  to  the  cavo-surface  angle  by  making  a  slight  concavity  from 
the  incisal  retention  to  the  cavo-surface  angle  with  a  round  bur.  This 
deepening  between  the  labial  and  lingual  cavo-surface  angles  will 
thicken  the  gold  to  the  very  edge.  Such  a  concavity  cannot  be  cut 
deep  or  the  retention  might  be  destroyed  and  the  enamel  plates  under- 
mined.    (Figs.  160,  161,  162,  163.) 

The  enamel  wall  may  be  trimmed  and  beveled  with  the  chisel, 
round  bur  or  strip,  and  where  there  is  abundance  of  space  the  disk. 
The  disk  and  strip  are  very  treacherous  instruments  but  in  the  hands 
of  those  who  are  willing  to  study  their  peculiarities  are  the  most  tract- 
able at  our  command.  A  strip  narrower  than  the  inciso-gingival  di- 
ameter of  the  cavity  held  tight  and  carried  back  and  forth  without 
pressure  against  the  walls  will  finish  an  enamel  wall  in  these  cavities 
as  no  other  instrument  can.  A  disk  in  large  cavities  may  be  satis- 
factory but  it  should  not  be  permitted  to  reach  the  junction  of  the 
gingival  wall  with  the  labial  or  lingual  or  too  much  bevel  will  be  the 
result.     A  round  bur  is  better  adapted  for  these  positions. 


202  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

If  the  cuttings  are  now  removed  from  the  cavity  and  the  tissue  over 
the  pulp  carefully  inspected  the  filling  may  be  inserted. 

Lower  incisors  and  cuspid  cavities  demand  special  treatment 
in  so  far  as  these  teeth  differ  in  form  from  the  uppers.  They  have 
smaller  and  longer  crowns  than  the  uppers.  They  are  much  narrower 
mesio-distally  and  the  contact  points  are  always  at  the  incisal  edges. 
The  latter  fact  together  with  concave  proximal  surfaces  at  the  gum 
line  make  operations  prone  to  failure.  The  teeth  are  so  thin  that  the 
labial  and  lingual  plates  of  enamel  have  but  little  dentin  between  them, 
and  if  retention  be  cut  deeply  between  these  plates  for  the  incisal  reten- 
tion the  corner  is  almost  certain  to  fracture.  In  some  of  these  teeth 
the  pulp  extends  far  into  the  crown  and  is  a  source  of  difficulty. 
Cavities  which  do  not  extend  close  to  the  incisal  edge  are  simple  in  prepa- 
ration and  the  fillings  of  fair  permanency.  There  is  little  or  no  stress 
on  small  fillings  in  the  lower  anterior  teeth.  Retentive  form  is  made 
as  in  the  upper.  In  fact  the  preparation  is  the  same  except  that  there 
is  not  as  much  space  between  the  teeth,  and  all  the  instruments  should 
be  smaller.  Retentive  form  and  convenience  angles  may  be  cut  with 
a  J  mm.  inverted  cone  bur  holding  the  shaft  at  right  angles  to  the 
long  axis  of  the  tooth.  The  base  of  the  bur  may  be  carried  down  the 
lingual  wall  and  sunk  into  the  gingival  at  the  linguo-gingivo-axial  angle. 
The  labio-gingivo-axial  angle  may  be  cut  in  like  manner  using  a  bur  in 
the  right  angle  hand-piece.  The  incisal  retention  may  be  cut  as  in  the 
uppers. 

3.  Preparation  of  proximal  cavities  in  incisors  and  cuspids  which 
involve  the  incisal  angle. 

General  Considerations. — Proximal  cavities  in  incisors  and  cuspids 
which  have  become  so  extensive  as  to  involve  the  incisal  angle  have 
usually  been  filled  before.  The  conditions  which  caused  the  failure 
of  the  former  filling  will  be  of  value  in  determining  what  form  "of 
preparation  is  desirable  for  the  new  cavity.  In  such  cases  as  have 
not  been  filled  before  there  is  often  difficulty  in  deciding  whether  the 
incisal  angle  should  be  cut  away  or  not.  Corners  of  enamel  often 
stand  the  force  brought  upon  them  before  the  filling  is  inserted  and 
break  off  shortly  afterwards.  There  may  be  two  reasons  for  this, 
a  tooth  with  a  cavity  in  it  is  usually  saved  a  little  in  mastication  but 
as  soon  as  made  comfortable  by  a  filling  it  receives  full  force  upon  it. 
Or  the  corner  of  enamel  may  be  checked  during  the  insertion  of  the 
gold  and  come  away  later.  It  is  a  safe  practice  to  remove  a  corner 
of  enamel  when  it  has  not  a  support  of  dentin  if  the  cavity  is  to  be 
filled  with  gold-     As  patients  become  older  the  enamel  is  more  and 


SMOOTH    SURFACE    CAVITIES.  203 

more  worn  away  and  seems  to  check  and  split  more  readily  than 
thicker  tissue.  This  is  especially  true  where  pr.oximal  fillings  have 
failed  from  wearing  away  of  the  tooth  tissue  leaving  the  filling  to  carry 
too  much  stress.  The  margins  of  cavities  in  such  teeth  demand  free 
cutting  away  of  tissue  and  careful  operating  to  prevent  checking  of 
the  edges. 

The  character  of  the  articulation,  the  peculiar  motion  of  the  teeth 
on  each  other  in  mastication  and  the  force  of  the  occlusion  all  influence 
the  operator  in  deciding  the  form  of  preparation.  In  most  of  these 
extensive  operations  failure  does  not  occur  from  primary  decay  about 
the  margins,  but  is  secondary  to  the  shifting  of  the  filling  or  checks 
in  the  enamel.  If  a  patient  should  have  no  molars  and  bicuspids 
suitable  for  mastication  large  fillings  in  the  incisors  need  to  be  much 
more  firmly  seated  than  if  there  were  good  posterior  teeth  for  masti- 
cation. Teeth  which  come  together  with  a  kind  of  anterio-posterior 
motion,  sliding  the  lowers  from  the  labio-incisal  angle  of  the  uppers  to 
the  gingival  will  drive  almost  any  filling  from  the  upper  teeth.  And 
if  the  lower  teeth  happen  to  require  fillings,  they  will  be  as  likely  to 
fail  as  the  uppers. 

Outline  Form. — The  determination  of  the  outline  form  in  proxi- 
mal cavities  which  involve  the  incisal  angle  is  not  one  of  extension  for 
prevention  in  the  ordinary  acceptation  of  the  practice.  It  is  extension 
to  more  securely  anchor  the  filling  rather  than  to  prevent  decay. 
The  proximal  surfaces  are  usually  so  far  extended  before  such  an 
operation  is  contemplated  that  no  further  extension  is  necessary  to 
prevent  recurrence  of  caries  on  these  surfaces.  The  outline  form 
depends  on  the  age  of  the  patient,  the  extent  of  the  caries,  the  thickness 
of  the  tooth,  the  amount  of  wear  on  the  incisal  edge,  the  friability  of 
the  enamel  and  the  character  of  the  occlusion.  Depending  upon  these 
conditions  there  are  five  methods  of  preparation  open  to  the  operator. 
The  first  to  consider  is  a  modification  of  the  method  used  in  preparing 
proximal  cavities  which  do  not  involve  the  incisal  angle.  The  indi- 
cations for  this  form  of  preparation  are  thin  teeth,  young  patients, 
not  very  heavy  occlusion,  not  much  of  the  incisal  edge  involved  and 
not  much  undermining  of  the  corner. 

Resistance  Form. — The  seat  and  labial  and  lingual  walls  are 
prepared  as  already  described,  except  that  the  seat  is  made  broader 
and  longer  and  the  grooves  are  made  deeper.  The  filling  will  be 
called  upon  to  bear  heavier  stress  than  those  described  in  the  former 
section  and  requires  a  greater  seat.  The  labial  and  lingual  margins 
should  be  a  straight  line  from  the  incisal  to  the  point  where  they  curve 
to  form  the  gingival  wall. 


204  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

Retentive  Form. — Much  care  is  necessary  to  avoid  cutting  out 
all  the  dentin  between  the  labial  and  the  lingual  enamel  plates  in 
cutting  the  incisal  retention.  To  be  of  the  most  value  this  retention 
must  be  as  near  the  point  of  stress  as  possible  and  large  enough  to 
contain  a  sufficient  bulk  of  gold  to  have  strength  to  resist  the  forces 
of  dislodgment.  The  horn  of  the  pulp  is  not  always  secure  from  an 
accident  in  cutting  this  retention.  It  is  generally  sufiEicient  to  make  the 
occlusal  wall  of  this  retention  at  right  angles  to  the  long  axis  of  the 
tooth,  but  to  be  certain  of  doing  this  it  is  well  to  aim  to  make  the 
depth  of  the  retention  closer  to  the  incisal  than  that  at  the  axial  wall. 
Technique. — With  a  wide  chisel  cut  away  the  corner,  shaving 
both  the  labial  and  lingual  to  the  gingival.  Some  patients'  only  fear 
is  the  slipping  of  the  instrument  and  wounding  the  gum  or  touching 
the  sensitive  portions  of  the  cavity.  In  such  cases  a  coarse  disk  or  a 
thin  stone  will  trim  away  the  enamel  corner  readily  and  with  less 
anxiety  to  the  patient.     Remove  the  softened  dentin  and  form  the 

seat  with  an  inverted  cone  bur  i  mm.  in  di- 
ameter which  may  be  held  parallel  with  the 
long  axis  of  the  tooth  and  carried  into  the 
labio-  and  linguo-gingivo-axial  angles,  cutting 
deeply  into  the  dentin  at  these  points  and 
P      ^g  F       fi        carrying    a  groove    towards  the   incisal  less 

than  half  way.  The  incisal  retention  may  be 
cut  with  an  inverted  cone  bur  held  at  right  angles  to  the  axial  wall  giving 
thecornerof  the  bur  a  catch  into  the  dentin  some  distance  gingivally  to 
the  final  occlusal  wall.  Slight  grooves  may  now  be  cut  toward  the 
gingival  from  the  incisal  retention.  A  disk  is  the  only  instrument  to 
finish  the  enamel  walls.  It  can  be  held  to  cut  the  enamel  parallel  with 
the  length  of  the  rods  and  then  to  slightly  bevel  the  outer  third.  The 
incisal  cavo-surface  angle  will  bear  considerable  bevel.  Remove  any 
remaining  decay  from  the  axial  wall  and  clean  up  the  cavity  walls. 
(See  Figs.  164  and  165.) 

The  second  method  is  suitable  in  thin  teeth,  young  patients,  incisal 
surface  not  much  worn  nor  not  much  involved,  corner  undermined. 
Chiefly  useful  in  laterals.  Pits  and  grooves  in  the  lingual  surface  may 
be  included  in  such  a  preparation. 

The  outline  form  is  the  same  as  in  the  last  case  except  that  there 
is  a  tongue  or  dovetail  cut  in  the  lingual  surface  at  least  one  and  a 
half  mm.  from  the  incisal  edge  depending  upon  the  form  of  this  sur- 
face. The  margins  of  the  dovetail  should  join  with  the  lingual  wall  in 
rounded  corners. 


SMOOTH    SURFACE    CAVITIES.  2O5 

The  resistance  form  at  the  gingival  is  the  same  as  in  the  last  case. 

The  retentive  form  in  the  incisal  region  is  entirely  different. 
Instead  of  cutting  between  the  labial  and  lingual  plates  as  in  the  former 
case  the  incisal  retention  is  cut  into  the  lingual  surface  in  the  form  of 
a  dovetail.  The  dovetail  is  cut  about  one  and  a  half  mm.  in  depth, 
depending  upon  the  thickness  of  the  tooth  and  the  nearness  of  the 
pulp.  The  direction  depends  upon  whether  there  are  defects  in  the 
enamel  of  the  lingual  surface  or  not.  It  is  generally  advisable  to 
make  this  retention  at  right  angles  to  the  proximal  wall  and  about 
one  and  a  half  mm.  inciso-gingivally  and  about  one  and  a  half  to  two 
mm.  mesio-distally.  To  be  of  the  greatest  value  as  retention  it 
must  be  cut  as  near  as  possible  to  the  incisal  but  must  not  be  so  near 
as  to  weaken  the  edge. 

Technique. — The  technique  up  to  cutting  the  supplementary 
retention  in  the  lingual  has  already  been  described.  It  is  always 
difficult  to  control  the  hand-piece  to  cut  into  the  lingual  surface  of  any 


Fig.  166.  Fig.  167  Fig.  168 

tooth  and  it  is  especially  difficult  to  do  so  in  this  case,  if  it  becomes 
necessary  to  use  the  right  angle.  Where  this  form  of  preparation  is 
advisable  the  lingual  surface  is  usually  markedly  concave  inciso-gingi- 
vally thus  making  it  almost  impossible  to  reach  it  with  the  straight 
hand-piece.  Unless  the  operator  has  confidence  in  his  ability  to  hold 
the  hand-piece  and  operate  through  the  mouth  mirror  it  is  better  to 
raise  the  chair,  tip  the  patient's  head  back  and  operate  by  direct  view. 
A  No.  ^  or  I  mm.  inverted  cone  bur  should  be  held  at  right  angles 
to  the  lingual  surface  of  the  tooth,  starting  the  corner  of  the  bur  on  the 
lingual  wall  of  the  cavity  at  the  junction  of  the  enamel  with  the  dentin. 
This  bur  will  cut  a  slot  the  full  depth  of  the  enamel  and  the  necessary 
distance  towards  the  opposite  side  of  the  tooth.  The  enamel  edges 
should  be  cut  back  and,  if  need  be,  the  slot  cut  larger  and  made  reten- 
tive in  form,  that  is,  the  incisal  and  gingival  walls  must  be  slightly 
undercut.     (Figs.  i66,  167  and  168.) 

The  third  method  of  preparation  is  indicated  in  thin  teeth,  corner 
undermined,  edge  much  involved,  lingual  plate  of  enamel  badly  de- 
cayed, and  heavy  occlusion  and  appearance  of  gold  not  a  serious 


2o6 


PREPARATION    OF    CAVITIES    FOR    FILLINGS. 


objection.  In  such  cases  there  is  a  step  cut  in  the  incisal  surface,  its 
width  depending  upon  the  extent  of  the  destruction  of  the  cutting 
edge.  As  a  rule  the  step  should  extend  mesio-distally  farther  than  the 
width  of  the  filling  to  be  supported.  The  depth  depends  upon  the 
weight  of  occlusion  and  the  thickness  of  the  tooth. 

Technique. — When  it  has  been  decided  to  cut  across  the  incisal 
exposing  the  gold  on  the  labial  surface  a  stone  is  the  most  suitable 
instrument  to  begin  with.  Cut  the  incisal  edge  down  the  width  and 
depth  required.  Prepare  the  proximal  cavity  as  in  case  two.  With 
an  inverted  cone  bur  cut  a  groove  from  the  proximal  cavity  across  the 
step  between  the  labial  and  lingual  enamel  plates,  deepening  and 
enlarging  the  groove  at  its  extremity.  A  good  deal  of  care  is  necessary 
in  cutting  this  groove  to  keep  it  from  coming  too  close  to  the  labial 
plate  and  at  the  same  time  have  it  large  enough  to  contain  sufficient 
gold  to  have  strength. 


Fig.  169. 


Fig.  170. 


Fig.  171. 


The  fourth  method  is  more  frequently  applicable  than  either  of  the 
last  two  described.  This  method  of  preparation  was  first  described 
by  Dr.  Johnson  and  takes  his  name.  It  is  indicated  in  thick  teeth, 
much  worn,  corner  undermined,  edge  much  involved,  heavy  occlusion, 
brittle  enamel,  old  patients,  lingual  surface  not  too  much  involved.  The 
successful  preparation  of  such  a  cavity  and  filling  it  with  gold  demands 
much  consideration  before  it  is  undertaken  and  careful  manipulation 
afterwards. 

Technique. — The  seat  and  proximal  surface  are  prepared  as 
in  the  last  two  cases.  Dependence  for  the  retention  of  the 
filling  is  in  the  step  cut  across  the  incisal.  The  step  does  not 
involve  the  labial  plate  and  yet  the  occlusal  surface  is  completely 
covered  with  gold.  The  step  is  largely  at  the  expense  of  the  lingual 
surface.  The  labial  wall  must  in  consequence  be  cut  with  a  definite 
angle  with  the  axial  wall.  The  labial  wall  in  the  step  must  also  meet 
the  pulpal  wall  with  a  definite  angle  to  give  the  necessary  resistance  to  a 
heavy  occlusion  coming  against  the  lingual  surface  of  so  large  a  filling. 

The  outline  from  a  labial  view  is  shown  in  Figure  169.  There  is 
no  exposure  of  gold  except  as  a  proximal  filling.     If  the  incisal  sut- 


SMOOTH    SURFACE    CAVITIES. 


207 


Fig.  172. 


face  has  been  sufficiently  worn  to  expose  the  dentin  the  outline  will 
show  the  whole  occlusal  surface  faced  with  gold.  (Fig.  170,)  The 
lingual  outline  will  show  almost  a  third  of  the  surface  covered  with 
gold.  (Fig.  171.)  Those  surfaces  of  the  tooth  which  are  exposed  to 
heavy  occlusion  are  covered  with  gold  and  those  surfaces 
which  are  exposed  to  view  from  without  show  but  little 
gold. 

An  inverted  cone  bur  held  against  the  axial  wall  at 
right  angles  to  the  long  axis  of  the  tooth  will,  if  carried 
across  the  incisal,  cut  the  step  about  i  mm.  in  depth.  This 
first  cut  must  be  kept  well  to  the  lingual  or  the  labial 
plate  may  be  so  thin  as  to  expose  the  gold  through  the  enamel. 
The  lingual  plate  may  now  be  trimmed  away  with  the  chisel. 
Usually  it  is  necessary  to  carry  the  inverted  cone  bur  across  the 
incisal  again  to  make  the  step  flat  and  at  right  angles  to  the  stress. 
The  extremity  should  be  deepened  to  give  additional  strength  and  to 
resist  tipping.  The  groove  through  the  dentin  forming  the  step  should 
not  be  more  than  ^  mm.  deeper  than  the  lingual  wall  except  as  it 
approaches  the  extremity  where  it  may  be  slightly  deeper,  while  at  the 
same  time  the  lingual  wall  is  not  trimmed  away  so  much  at 
this  point.  There  may  in  some  cases  be  some  difficulty  in 
obtaining  sufficient  resistance  to  forces  which  may  happen 
to  be  applied  to  the  labial  surface.  But  as  a  rule  fillings 
are  rarely  tipped  to  the  lingual. 

Finishing  the  enamel  walls  demands  a  careful  study  of 
the  direction  of  the  enamel  rods  at  every  point.  The 
labial  wall  of  the  step  may  be  beveled  with  a  fissure  bur,  a  disk  or 
a  round  bur.  This  wall  is  sloped  from  the  junction  of  the  labio- 
incisal  angle  to  the  pulpal  wall  of  the  step.  The  extremity  of  the  step 
is  best  trimmed  with  a  round  bur.  The  lingual  wall  of  the  step 
must  have  a  slight  bevel  and  join  with  the  proximal  lingual  wall 
in  a  rounded  form.  A  sharp  corner  at  this  junction  would  invite 
failure  either  during  the  insertion  of  the  filling  or  after- 
wards by  the  occlusion.  At  the  junction  of  the  labial 
wall  of  the  step  with  the  proximal  wall  is  a  source  of  weak- 
ness if  a  sharp  angle  is  left  to  the  enamel.  A  small  disk  in 
the  right  angle  will  reach  the  lingual  cavo-surface  angle  and 
also  the  labial. 

The  fifth  method  is  applicable  in  those  cases  where  there 
is  an  edge  to  edge  bite,  wearing  the  teeth  down  to  expose  the  dentin 
and  perhaps  loosening  the  incisal  retention  in  a  small  proximal    fill- 


FiG.  173. 


Fig.  174. 


2o8  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

ing.  There  is  not  much  of  the  incisal  edge  lost  and  yet  a  proximal 
lilling  cannot  be  retained  because  of  the  rapid  wearing  of  the  tooth 
and  the  difficulty  of  cutting  an  incisal  retention.  The  surest  method  to 
follow  is  to  cut  the  step  clear  across  the  incisal  including  all  the  exposed 
dentin  and  beveling  both  the  labial  and  lingual  enamel  walls  toward 
the  pulpal  wall  of  the  step.  Of  course,  enough  of  these  walls  must  be 
cut  down  to  face  the  whole  end  of  the  tooth  with  gold.  The  prepara- 
tion of  the  proximal  cavity  should  be  done  as  before  described  except 
that  it  does  not  require  any  provision  for  retention  because  the  step 
will  provide  all  the  resistance  necessary.  There  is  little  or  no  force 
to  drive  the  filling  to  the  labial  or  the  lingual  because 
there  is  little  loss  of  these  surfaces.  The  chief  point  of 
difficulty  in  preparation  is  at  the  junction  of  the  proxi- 
mal cavity  with  the  step.  There  must  be  bulk  enough  of 
gold  at  this  point  to  ensure  against  stretching.  If  a  sharp 
corner  is  left  at  this  junction  it  tends  to  leave  a  point  to 
start  the  stretching  of  the  gold.  The  technique  of  preparing  this 
cavity  is  so  much  like  those  just  described  that  it  is  not  necessary  to 
repeat  it.  (Figs.  172,  173  and  174.) 

Shoeing. — There  is  a  class  of  cavities  met  with  in  old  patients  so 
similar  to  the  one  described  in  the  previous  paragraph  that  it  might 
not  be  out  of  place  to  describe  their  preparation  here.  They  are 
strictly  speaking  occlusal  cavities  but  they  are  not  similar  in  origin 
to  other  occlusal  cavities  already  described.  As  patients  advance 
in  years  their  teeth  become  worn  until  the  dentin  is  reached  which  soon 
hollows  out  in  a  cup  shape  on  the  occlusal  surface.  This  exposed 
dentin  often  becomes  quite  sensitive  to  acids  and  in  fact  is 
dissolved  or  worn  away  so  rapidly  that  the  pulp  is  often 
involved.  The  teeth  become  much  shortened  and  unsightly. 
To  foresee  and  prevent  such  unhappy  results  is  the  duty 
of  the  dentist.  If  a  tooth  seems  to  be  cupped  out  even 
though  there  is  little  direct  antagonism  of  the  opposing  tooth,  p^^  ^  ^ 
it  is  well  to  prepare  a  cavity  for  the  reception  of  a  gold 
filling  which  will  cover  the  exposed  dentin  and  prevent  its  further 
wear.  The  anterior  teeth,  both  upper  and  lower,  are  chiefly  subjected 
to  such  wearing  because  so  many  people  have  lost  their  molars  and 
bicuspids. 

Technique. — The  technique  of  preparation  is  simple.  This 
eburnated  dentin  is  not  usually  sensitive  to  cut.  An  inverted  cone 
bur  can  be  held  parallel  with  the  long  axis  of  the  tooth  and  car- 
ried across  the  occlusal  surface  cutting  a  groove  about  a  millimeter 


PULPLESS    INCISORS    HAVING    LARGE    PROXIMAL    CAVITIES.       209 

in  depth.  As  the  tooth  is  worn  down  a  good  deal  it  is  quite  thick 
labio-lingually  giving  ample  room  for  good  anchorage.  The  extremi- 
ties of  the  groove  should  not  come  too  close  to  the  mesial  or  distal  sur- 
faces. The  inverted  cone  will  make  all  the  undercuts  necessary  to  keep 
the  filling  from  being  lifted  from  the  cavity  which  is  the  only  force  that 
can  dislodge  it.  The  walls  should  be  sloped  into  the  cavity  and  the 
finished  filling  should  come  over  the  entire  end  of  the  tooth  and  be  of 
sufficient  thickness  to  resist  stretching  or  curling  up  at  the  edges 
from  constant  hammering  of  the  opposing  teeth.     (Figs.  175  and  176.) 

PULPLESS  INCISORS  HAVING  LARGE  PROXIMAL  CAVITIES. 

While  the  majority  of  incisors  which  have  lost  their  pulps  and  have 
large  proximal  cavities  require  to  be  filled  with  porcelain  or  should  be  cut 
off  and  restored  by  a  crown  there  are  cases  which  should  be  filled  with  gold. 

The  difficulty  in  preparing  such  cavities  is  to  avoid 
cutting  away  the  dentin;  because  so  much  has  been 
already  lost  by  getting  access  to  remove  the  pulp  there  is 
no  strength  left  to  retain  and  support  a  filling.  In  thin 
teeth  not  much  worn  on  the  incisal,  a  fair  amount  of  dentin, 
and  not  much  filling  exposed  to  occlusion  the  chief  reten-  yig  m 
tion  may  be  obtained  in  the  pulp  chamber.  The  pulp 
chamber  should  be  filled  with  cement  and  then  the  gingival  wall  cut 
wide  and  flat  as  if  the  pulp  had  receded  markedly.  Grooves  may 
be  cut  in  the  labial  and  lingual  walls  part  of  the  distance  to  the  in- 
cisal, depending  upon  the  thickness  of  the  tooth.  The  incisal  reten- 
tion should  be  cut  with  an  inverted  cone  bur  placing  it  into  the  pulp 
chamber  and  cutting  towards  the  incisal,  thus  getting  a  good  undercut 
without  going  near  the  incisal.  The  aim  should  be  to  make  up  in 
bulk  of  gold  (the  greater  portion  of  which  will  be  in  the  pulp  cham- 
ber) for  not  getting  the  retention  as  near  the  point  of  stress  as  in 
other  cases. 

If  the  tooth  is  thin  and  the  decay  together  with  the  cut- 
ting to  remove  the  pulp  has  involved  a  good  deal  of  dentin 
any  further  cutting  of  dentin  is  contra-indicated.  It  is 
better  to  depend  for  retention  of  the  filling  upon  a  post 
cemented  in  the  root  canal  and  extending  far  enough  into 
Fig.  178.  |-]^g  cavity  proper  to  give  a  good  attachment  for  the  filling. 
There  is  no  further  preparation  of  the  cavity  required  than  to  give  it 
proper  outline  form  and  resistance  form;  the  post  will  provide  the 
retention.  The  technique  of  inserting  a  post  in  an  incisor  so  that  a 
gold  filling  may  be  condensed  around  it  is  not  always  easy.  Select  a 
14 


2IO  PREPARATION    OF   CAVITIES    FOR    FILLINGS. 

piece  of  iridio-platinum  wire  No.  i6  for  a  central  or  cuspid  and  No. 
i8  for  a  lateral.  Ream  out  the  canal  about  five  to  seven  mm.  in 
depth,  not  the  same  diameter  the  full  depth,  as  it  is  usually  better 
to  taper  the  wire  slightly.  To  do  this  it  is  best  held  in  a  pin  vise  for 
filing.  With  heavy  pliers  give  it  the  necessary  bend  to  enter  the  canal 
and  project  in  the  center  of  the  cavity  so  that  gold  may  be  packed 
between  it  and  the  cavity  walls  and  also  cover  it  at  the  surface.  To 
accomplish  this  it  will  be  necessary  to  fit  the  pin  in  the  cavity,  mark 
it  about  the  proper  length  and  remove  it  to  cut  it  off.  Then  file  it 
down  to  some  extent  and  perhaps  flatten  that  portion  extending  into 
the  cavity  with  a  hammer  on  the  anvil  so  as  to  conform  with  the  flat 
shape  of  the  tooth  labio-lingually.  Before  setting  in  cement  it  should 
be  tried  in  and  note  taken  of  its  length,  its  size  and  proper  position 
to  allow  gold  to  be  packed  around  it,  and  its  capability  of  retaining  the 
filling.     (Figs.  177  and  178.) 

4.  Preparation  0}  cavities  in  bicuspids  and  molars  which  do  not 
involve  the  occlusal  surface. 

While  the  general  rule  is  laid  down  that  all  proximal  cavities  in 
bicuspids  and  molars  should  be  extended  through  to  the  occlusal  sur- 
face there  are  cases  in  which  it  is  better  practice  not  to  do  so.  In  the 
very  old,  the  very  young  and  in  cases  of  immunity  to  caries  it  is  not 
always  wise  to  extend  proximal  cavities  to  the  occlusal  surface,  but 
such  operations  must  be  looked  upon  as  temporary  in  character. 

There  is  more  or  less  recession  of  the  gums  around  the  necks  of 
the  teeth  as  age  advances.  The  gum  tissue  which  once  filled  the  inter- 
proximal space  does  not  more  than  half  fill  it  at  fifty  or  sixty  years  of 
age.  These  open  spaces  between  the  teeth  serve  as  pockets  for  the 
collection  of  food  which  ferments  and  acts  as  a  starting  point  of  decay. 
The  cementum  is  exposed  and  decays  rapidly.  In  such  cavities  which 
are  usually 'shallow  and  girdle  the  tooth  it  would  be  manifestly  unwise 
to  extend  through  to  the  occlusal  surface.  There  is  plenty  of  access, 
the  contact  is  far  occlusal  to  the  cavity  and  the  tooth  is  thick  enough 
occluso-gingivally  to  bear  any  stress  which  might  come  upon  it.  Be- 
sides old  patients  should  be  treated  with  a  good  deal  of  consideration. 
Radical  and  painful  operations  should  be  reserved  for  those  in  the  vigor 
of  life.  Old  people  dread  dental  operations  even  more  than  the  child 
who  has  been  told  of  the  horrors  of  the  dental  chair. 

For  many  reasons,  as  has  already  been  said,  it  may  not  be  wise  to 
make  a  full  extension  of  cavities  occurring  in  the  proximal  surfaces  of 
the  teeth  of  the  very  young.  These  patients  are  often  so  nervous 
and  restless  in  the  dental  chair  that  anything  like  ideal  operating 


CAVITIES    IN    BICUSPIDS    AND    MOLARS.  211 

cannot  be  undertaken.  It  is  better  in  such  cases  to  do  temporary 
work  rather  than  create  a  dread  of  dental  operations  in  the  minds  of 
young  patients.  Again  the  warning  must  be  sounded  that  oversen- 
sitiveness,  etc.,  must  not  be  made  an  excuse  for  improper  extensions. 
While  we  must  all  admit  that  such  cases  are  met  in  practice  yet  there 
are  not  nearly  so  many  of  them  as  some  of  the  old  operators  would 
have  us  believe. 

Often  a  large  proximal  cavity  is  found  in  the  mesial  surface  of  a 
first  permanent  molar  and  after  it  has  been  opened  up  and  prepared 
for  filling  the  beginning  of  a  cavity  is  found  in  the  distal  surface  of 
the  second  bicuspid.  Now  comes  the  problem.  What  should  be 
done  with  such  a  defect  ?  If  it  is  left  without  a  filling  it  is  certain  to 
decay.  If  a  small  filling  is  inserted  whose  margins  are  in  contact 
with  the  adjoining  filling  recurrence  is  almost  certain  within  a  very  few 
years.  Should  the  whole  proximal  surface  together  with  the  neces- 
sary step  be  cut  out  now,  or  should  an  attempt  be  made  to  get  a  clear- 
ing margin  to  a  filling  confined  to  the  proximal  surface  ?  The  answer 
to  these  questions  depends  upon  the  conditions  present.  If  the  patient 
be  a  young  girl  and  caries  progressive  and  a  full  extension  w^ould  seem 
impossible  a  small  cavity  may  be  prepared.  It  must  be  explained  to 
the  patient  that  this  is  a  temporary  operation  which  will  need  careful 
examination  every  few  months.  Any  change  of  color  about  the  filling 
will  be  a  signal  for  its  removal.  By  this  method  perhaps  two  or  three 
years  have  been  gained  and  the  patient  at  this  time  will  be  glad  to 
have  a  more  permanent  operation  made.  If  the  patient  be  robust  and 
the  dentin  not  too  sensitive  and  a  tendency  to  caries  and  lack  of  care 
of  teeth,  the  cavity  should  be  prepared  in  the  most  ideal  manner.  Then 
there  is  the  middle  course  which  may  be  followed  if  there  is  a  marked 
immunity  to  caries.  The  cavity  may  be  extended  as  much  as  possible 
to  clear  the  margins  but  yet  confining  it  to  the  proximal  surface. 
There  are  many  cases  of  thick  necked  teeth  where  this  preparation 
will  have  fairly  good  cleansing  margins.  The  management  of  this 
type  of  case  in  practice  will  indicate  what  may  be  done  with  similar 
cavities  in  other  locations. 

Many  times  small  cavities  are  found  in  the  proximal  surfaces  of 
teeth  in  patients  of  middle  life  which  have  not  increased  in  size  for  years, 
or  perhaps  at  one  time  decay  was  rapid  but  for  some  cause  or  another 
has  ceased.  The  walls  of  these  cavities  will  be  dark  or  even  black  in 
color,  the  enamel  about  them  does  not  seem  to  have  its  normal  his- 
tological structure  when  cut,  the  dentin  in  the  bottom  of  the  cavity 
does  not  seem  to  be  sensitive.     In  some  of  these  cases  there  may  be  a 


212  PREPARATION    OF    CAVITIES    FOR    FILLINGS. 

slowly  progressing  caries  at  only  one  location  in  the  cavity.  Radical 
extensions  of  cavity  margins  are  not  indicated  in  such  cases.  It  is 
not  necessary  to  cut  such  cavities  through  to  the  occlusal  surface  if 
there  is  abundance  of  access  and  there  is  sufficient  thickness  of  tissue 
left  to  bear  the  forces  of  occlusion. 

Technique. — The  technique  of  preparing  proximal  cavities  in 
bicuspids  and  molars  which  do  not  involve  the  occlusal  surface  is 
quite  simple.  They  are  simple  cavities  and  are  prepared  as  buc- 
cal, labial,  or  lingual  cavities.  There  is  no  force  to  dislodge  the 
filling. 

5.  Preparation  0}  cavities  in  the  proximal  surfaces  of  bicuspids  and 
molars  which  involve  the  occlusal  surface. 

The  preparation  of  cavities  in  the  proximal  surfaces  of  molars  and 
bicuspids  opens  up  the  "question  of  extension  for  prevention"  again. 
While  there  may  be  excuses  for  not  extending  proximal  cavities  in 
the  anterior  teeth  there  cannot  be  the  same  excuses  for  not  doing  so  in 
the  bicuspids  and  molars.  These  teeth  are  wider  bucco-lingually 
than  the  anterior  teeth,  the  proximal  surfaces  are  often  flat  which  in  a 
measure  accounts  for  more  frequent  failures  in  these  teeth  than  in  the 
anterior  teeth.  The  bicuspids  and  molars  are  usually  closer  together 
and  rarely  as  well  cared  for  as  the  incisors. 

The  outline  form  depends  upon  the  age,  and  sex  of  the  patient, 
the  character  of  the  carious  process,  the  strength  of  the  closure  of  the 
jaws  and  the  friability  of  the  enamel.  The  extent  of  the  caries  is  a  fac- 
tor in  deciding  the  location  of  the  outline  only  when  it  has  gone  beyond 
the  susceptible  areas.  All  small  cavities  of  decay  are  extended  until 
immune  areas  are  reached.  The  gingival  wall  is  cut  away  until  the 
margin  of  the  filling  will  be  covered  by  healthy  gum  tissue.  The  buc- 
cal and  lingual  walls  are  extended  until  the  margins  are  quite  clear 
of  the  adjoining  teeth  and  may  be  kept  clean  by  the  action  of  the  lips, 
the  tongue,  the  tooth  brush  and  food  in  passing  over  them.  The 
outline  of  such  cavities  on  the  occlusal  surface  depends  to  some  extent 
upon  the  depth  and  direction  of  the  fissures.  While  cutting  proximal 
cavities  through  to  the  occlusal  gives  more  perfect  access  to  the  proxi- 
mal cavity  it  also  gives  an  opportunity  for  cutting  out  defective  grooves 
or  fissures  in  the  occlusal  surface  and  forming  a  step  for  the  filling 
which  is  the  chief  source  of  retention.  The  outline  in  the  occlusal 
should  be  formed  so  as  to  give  the  greatest  amount  of  retention  for 
the  filling  with  the  least  cutting  away  of  tissue.  The  buccal  and 
lingual  walls  should  be  parallel  and  at  right  angles  to  the  seat  of  the 
cavity.     There  should  be  no  acute  angles  or  irregularities  in  the  outline 


CAVITIES    IN    BICUSPIDS    AND    MOLARS.  213 

Technique. — In  the  ordinary  proximal  cavities  where  the  occluso- 
proximal  marginal  ridge  has  not  been  broken  away  and  but  slight 
defects  in  the  occlusal  fossa  the  simplest  method  of  procedure  is  to 
cut  into  the  fissure  in  the  occlusal  with  an  enamel  drill  or  fissure  bur 
about  ^  mm.  in  diameter.     This  instrument  should  be  carried  right 
through  the  marginal  ridge  leaving  a  slot,  the  edges  of  which  can  be 
broken  down  with  a  chisel.     If  the  cavity  be  a  distal  one,  Black's  side 
instruments  work  admirably.     At  this  juncture  the  decay  in  the  proxi- 
mal cavity  may  be  removed  with  spoon  excavators  and  the  cavity  washed 
out  with  a  stream  of  tepid  water.     If  the  rubber  is  now  applied  and 
the  cavity  dried  the  full  degree  of  extension  may  be  decided  upon.     In 
the  great  majority  of  cases  where  the  proximal  decay  has  been  at  all 
extensive  the  buccal  and  lingual  walls  may  be  cut  back  with  the 
chisel.     If  the  enamel  is  supported  by  dentin  it  will  be  impossible  to 
cut  it  back  with  the  chisel  until  the  dentin  is  first  removed.     This  may 
be  done  with  an  inverted  cone  bur  which  is  placed  in  the  seat  of  the 
cavity  and  carried  from  the  center  to  the  buccal  and  then  carried  towards 
the  occlusal  undermining  the  enamel.     This  may  be  repeated  on  the 
lingual  wall  and  if  the  gingival  needs  extension  it  may  be  cut  with  the 
same  instrument.     The  chisel  will  now  shave  back  the  enamel  slightly 
beyond  the  point  of  the  removal  of  the  dentin.     A  narrow  necked 
chisel  may  be  passed  between  the  teeth  to  shave  the  gingival  enamel 
away.     In  many  of  these  cases  it  is  difficult  to  control  an  inverted 
cone  bur  along  the  seat  and  keep  it  from  jumping  out  of  the  cavity 
or  dropping  dangerously  near  the  pulp.     If  an  Ivory  matrix  is  adjusted 
the  bur  may  be  held  tightly  against  it  while  it  is  cutting  and  thus  pre- 
vented from  doing  what  was  not  intended.     The  outline  of  the  step 
should  be  completed  by  carrying  an  inverted  cone  bur  i  mm.  in  di- 
ameter as  far  to  the  opposite  side  of  the  tooth  as  the  fissures  extend  and 
at  this  point  carried  to  the  buccal  and  lingual  enough  to  make  the  ca\  ity 
at  the  extremity  a  little  more  than  ^  mm.  wider  bucco-lingually  than 
any  other  point  in  the  step.     Instead  of  widening  the  extremity  of  the 
step  as  just  described  it  may  be  deepened  about  half  a  millimeter  and 
slightly  undercutting  buccally  and  lingually.     This  method  is  applic- 
able where  there  are  no  fissures  or  angular  grooves  requiring  removal. 
There  is  always  some  difficulty  in  properly  trimming  the  enamel  at  the 
junction  of  the  occlusal  outline  with  the  proximal.     A  careful  study 
of  the  behavior  of  the  enamel  as  it  is  cut  away  is  the  only  guide  to  the 
proper  beveling. 

The    resistance    form  of    cavities   in   bicuspids  and   molars  is 
of  first  importance  because  these  teeth  and  their  fillings  are  called. 


214  PREPARATION    OF   CAVITIES    FOR    FILLINGS. 

upon  to  bear  heavy  pressure  and  sudden  impacts  from  hard  substances 
in  the  closure  of  the  jaws.  The  chief  dependence  to  resist  this  heavy 
stress  must  be  in  a  flat  seat  and  step  which  are  at  right  angles  to  the 
force  applied.  There  should  be  no  dependence  put  in  grooves  or  under- 
cuts in  the  walls  of  the  cavity  to  resist  the  stress  of  occlusion. 

As  the  outline  form  is  being  gained  the  resistance  form  is  being 
provided  for.  The  inverted  cone  bur  which  was  swept  across  the 
gingival  wall  made  the  seat  flat  from  buccal  to  lingual  and  from  the 
cavo-surface  angle  to  the  axial  wall.  And  as  the  step  was  being  cut 
out  with  the  same  form  of  instrument  it  was  made  flat.  The  junction 
of  the  axial  wall  with  the  step  should  be  slightly  rounded  just  so  as  not 
to  leave  a  sharp  corner  which  might  be  the  starting  point  of  stretching 
the  gold  under  the  heavy  biting  in  some  mouths.  If  decay  has 
removed  a  good  deal  of  the  axial  wall  thus  lessening  the  area  of 
the  step  it  may  be  restored  with  cement  and  formed  as  if  it  were 
dentin. 

The  retentive  form  is  largely  provided  for  in  the  resistance  form 
and  the  outline  form.  However,  there  are  forces  which  may  dislodge 
fillings  in  bicuspids  and  molars  though  they  would  resist  the  heaviest 
of  stress.  Such  fillings  must  be  so  placed  as  to  prevent  their  being 
tipped  from  the  cavity  or  lifted  directly  out.  The  tipping  stress  is 
overcome  by  the  dovetail  in  the  occlusal  surface  and  by  providing 
sufficient  bulk  of  gold  in  the  step  so  that  portion  of  the  filling  in  the 
proximal  surface  may  not  be  broken  away  from  the  step.  As  the 
buccal  and  lingual  walls  are  being  cut  back  the  inverted  cone  bur  is 
allowed  to  cut  deeply  into  the  bucco-gingivo-axial  angle  and  carried 
occlusally  about  two-thirds  the  distance  to  the  step,  thus  making  the 
slightest  grooves,  which  widens  the  cavity  bucco-lingually  at  the 
seat  and  not  at  the  step.  It  must  not  be  understood  that  the  outline 
is  wider  bucco-lingually  at  the  seat  than  at  the  step.  It  is  only  in  the 
depth  of  the  cavity  that  it  is  wider.  A  slight  undercut  in  the  step 
will  provide  against  the  lifting  of  the  filling  if  the  walls  cannot  be  wid- 
ened as  just  mentioned  or  if  the  proximal  cavity  is  to  be  filled  with  non- 
cohesive  gold  or  tin-and-gold,  and  finished  with  cohesive  gold. 

The  convenience  form  has  already  been  provided  for  in  the 
angles  cut  at  the  seat  and  in  opening  up  the  cavity  to  the  occlusal  to 
gain  free  access.  There  is  no  more  fatal  mistake  in  the  formation 
of  this  cavity  than  allowing  the  proximal  walls  to  diverge  as  they  ap- 
proach the  gingival.  Even  if  such  cavities  are  successfully  filled  the 
least  condensation  of  the  filling  after  it  is  inserted  will  result  in  the 
gold  drawing  away  from  the  margins. 


CAVITIES    IN    BICUSPIDS    AND    MOLARS. 


215 


The  enamel  walls  should  be  first  cut  in  the  length  of  the  rods  and 
then  the  cavo-surf ace  angle  beveled  the  required  amount  at  every  point. 
If  the  operator  notices  the  manner  of  cleavage  of  the  enamel  while 
trimming  the  walls  he  will  be  guided  in  their  final  polishing  and 
beveling.  Any  mistake  in  the  proper  bevel  of  the  enamel  is  sure  to 
be  followed  by  fractures  of  the  enamel  around  the  filling. 

Technique. — A  disk  will  trim,  bevel  and  polish  part  of  the  buccal 
and  lingual  walls  on  the  proximal  and  part  on  the  occlusal.  A  disk 
will  not  reach  the  margins  near  the  gingival  without  cutting  too  much 
bevel  nor  will  it  reach  the  walls  at  the  extremity  of  the  step.  These 
locations  must  be  trimmed  with  a  bur.  A  chisel  will  trim  the  gingival 
wall.  Darby-Perry  gingival  enamel  chisels  will  sometimes  do  good 
service  at  these  points.     (Figs.  179,  180,  181,  182,  183  and  184.) 

If  any  decalcified  tissue  remains  over  the  axial  or  pulpal  wall  it 
may  now  be  carefully  cut  away  and  the  cavity  cleared  of  any  chips. 

The  procedure  of  preparing  these  cavities  is  slightly  modified  if 
the  proximal  decay  is  extensive  enough  to   undermine  the  enamel 


Fig.  180. 


Fig    181,    Fig.  182 


Fig   183.     Fig.  184 


Fig   179, 

both  buccally  and  lingually.  In  such  cases  the  walls  are  readily  cut 
away  with  the  chisel  and  the  seat  is  easily  formed.  What  is  of  con- 
siderable moment  in  these  cases  is  the  support  of  the  buccal  and  lin- 
gual cusps  and  at  the  same  time  to  get  enough  resistance  form  for  the 
filling.  Caries  has  reduced  the  area  of  the  step  and  the  area  of  the 
seat  cannot  be  increased  by  cutting  into  the  tooth  until  the  axial  wall 
is  at  right  angles  with  the  seat  and  step,  without  involving  the  pulp. 
The  next  best  thing  to  having  a  step  of  dentin  is  to  have  one  of 
cement.  The  cement  serves  the  purpose  of  a  non-conducting  lining 
and  a  support  for  the  metal  filling. 

Lower  bicuspid  cavities  deserve  special  mention  inasmuch  as  they 
are  of  different  form  from  the  uppers.  Proximal  decay  in  lower  first 
bicuspids  which  have  low  lingual  cusps  must  be  prepared  as  the  ante- 
rior teeth.  The  groove  between  the  cusps  is  rarely  defective  in  the  low 
cusped  variety.  In  the  high  cusped  variety  there  are  usually  two 
pits  on  the  occlusal  separated  by  a  ridge  of  perfect  enamel  which  need 
not  be  cut  through  to  form  the  step  if  the  occlusion  is  not  heavy.     These 


2l6 


PREPARATION    OF    CAVITIES    FOR    FILLINGS. 


teeth  are  often  wide  enough  bucco-lingually  to  permit  of  the  whole 
cavity  being  dovetailed.  The  lower  second  bicuspids  demand  more 
resistance  form,  and  even  though  there  is  a  good  transverse  ridge  it 
should  be  cut  across  to  get  enough  resistance  and  retentive  form  to  re- 
tain a  large  proximal  filling. 

In  special  large  mesio-occlusal  cavities  in  upper  molars  there 
is  often  some  difficulty  in  managing  the  mesio-buccal  cusp  which 
has  become  undermined.  The  cusp  is  usually  high  and  not  well 
supported  by  dentin.  If  a  fissure  should  run  over  the  buccal  from  the 
central  fossa  then  there  is  no  doubt  about  what  should  be  done.  Cut 
the  whole  cusp  down  with  a  stone  as  far  distally  as  the  central  groove^ 
It  should  be  cut  low  enough  to  leave  room  to  be  covered  with  suffi- 
cient bulk  of  filling  material  to  bear  the  stress  of  mastication.  And 
if  it  be  cut  further  rootwards  as  it  approaches  the  central  groove 
giving  it  a  general  slant  to  that  portion  of  the  cavity  it  will  help  to  resist 
the  tipping  stress  on  the  filling.  The  same  method  of  managing  the 
disto-lingual  cusp  will  often  add  to  the  retention  of  the  filling  and  re- 
move a  weak  cusp  which  is  likely  to  be  fractured.  Mesial  cavities 
in  lower  molars  occasionally  involve  one  of  the  cusps  and  need  the 
same  treatment.     (Fig.  185.) 

There  is  a  class  of  cavities  in  molars  which  is  often  puzzling  to  the 
beginner.  They  occur  as  the  result  of  defective  enamel  over  the  whole 
occlusal  surface.  Caries  often  ceases  after  the  whole 
enamel  surface  is  stripped  off.  There  are  spots  of 
penetration  but  for  which  they  might  not  need  opera- 
tive interference.  The  pulps  are  alive  and  apparently 
normal  and  the  patient  under  fifteen  years  of  age.  It 
is  mostly  considered  wise  not  to  devitalize  such  pulps 
if  they  can  be  retained  alive.  Grind  off  any  project- 
ing spiculas  of  enamel.  Remove  the  decayed  tissue  with  spoons  and 
if  hard  remove  with  large  round  burs.  The  only  force  which  is  liable 
to  dislodge  a  filling  from  such  a  tooth  will  be  a  lifting  one. 
To  overcome  this  and  to  keep  the  filling  from  being 
forced  off  the  end  of  the  tooth  cut  a  continuous  groove 
with  an  inverted  cone  bur  all  the  way  around  the  tooth 
about  'midway  between  the  enamel  and  the  probable 
location  of  the  pulp.  A  groove  made  with  such  a  bur 
will  have  undercut  enough  to  resist  the  lifting  stress. 
If  a  groove  cannot  be  cut  all  the  way  round,  good  sized  pits  may  be 
cut  at  the  four  corners.  These  will  give  sufficient  hold  for  a  filling 
if  it  is  not  built  too  high.     (Fig.  186.) 


Fig.  185. 


Fig.  186, 


THE    TECHNIQUE    OF    INSERTING    A    SCREW    POST.  217 

THE  MANAGEMENT  OF  LARGE  PROXIMO-OCCLUSAL  CAVITIES  IN 
PULPLESS  BICUSPIDS. 

Bicuspids  are  so  narrow  mesio-distally  and  the  pulp  cavity  is  so 
situated  in  the  crown  that  when  the  necessary  cutting  is  done  to  re- 
move the  pulp  from  a  proximo-occlusal  cavity  there  is  little  dentin 
left  to  support  the  cusps.  It  usually  happens  that  if  a  bicuspid  has 
decayed  deeply  enough  in  one  surface  to  involve  the  pulp  the  opposite 
surface  is  also  defective.  This  increases  the  weakness  of  the  cusps. 
With  the  present  knowledge  of  inlays  it  is  hardly  ever  advisable  to 
fill  such  bicuspids  with  gold  foil.  The  malleting  of  so  large  a  filling 
is  sufficient  to  endanger  the  walls  by  wedging  the  gold  between  them. 
Very  occasionally  a  post  might  be  inserted  in  the  root  canal  of  a  bi- 
cuspid to  act  as  a  support  to  a  gold  filling.  Such  a  post  is  more  serv- 
iceable in  lower  bicuspids  where  the  transverse  ridge  is  not  often  de- 
fective and  the  post  serves  for  retention  without  cutting  a  step  across 
the  occlusal. 

THE   MANAGEMENT  OF  LARGE  CAVITIES  IN  PULPLESS  MOLARS. 

The  secret  of  success  in  filling  large  cavities  in  molars  is  to  cut 
away  the  enamel  freely.  Leave  as  little  enamel  exposed  to  occlusion 
as  possible.  Grind  it  low  enough  to  be  well  covered  with  filling  ma- 
terial. Enamel  exposed  to  occlusion  in  a  pulpless  molar  must  be  sup- 
ported by  a  large  bulk  of  dentin  or  failure  is  certain.  Posts  screwed  into 
the  root  canals  often  assist  in  supporting  a  large  proximo-occlusal 
filling  which  would  otherwise  have  to  be  supported  by  cutting  deeply 
into  the  dentin  of  the  tooth,  thus  unnecessarily  weakening  the  whole 
structure.  Large  cavities  in  the  lower  molars  rarely  need  a  post  for 
the  retention  of  the  filling.  The  pulp  chamber  may  be  used  for  this 
purpose  by  cutting  a  groove  around  its  walls  at  the  base.  The  bulk 
of  filling  in  the  chamber  will  be  strong  enough  to  resist  any  tipping 
stress  and  the  undercut  will  resist  the  lifting  force. 

THE  TECHNIQUE  OF  INSERTING  A  SCREW  POST. 

The  technique  of  inserting  a  screw  post  into  a  root  canal  for  the 
purpose  of  supporting  a  filling  or  a  tube  for  a  jacket  crown  is  simple 
and  yet  has  to  be  done  a  few  times  to  gain  speed  and  get  the  best  re- 
sults. The  screw  posts  which  are  the  most  suitable  have  square  heads 
with  a  tapering  thread  as  a  screw  nail.  The  thread  is  sharp  and  will 
cut  into  the  dentin  as  it  is  forced  into  the  canal.  Select  the  proper 
size  of  post,  ream  the  canal  slightly  smaller  than  the  post.     Screw  the 


2l8  PREPARATION   OF    CAVITIES   FOR   FILLINGS. 

post  in  and  out  a  couple  of  times.  Mark  the  point  on  the  post  when 
screwed  into  place  at  which  it  should  be  cut  off  to  be  properly  covered 
with  filling  material.  Remove  the  post,  nick  it  deep  enough  with  a 
file  so  as  it  will  twist  off  when  fully  twisted  down  to  place  after  being 
dipped  into  soft  cement  or  chlora  percha.  A  post  to  be  of  service 
should  not  extend  through  the  filling  nor  yet  be  so  short  that  the  fill- 
inty  cannot  be  thoroughly  packed  around  it.  If  the  post  is  intended 
to  resist  a  lifting  force  that  portion  of  it  which  is  in  the  filling  should  be 
riveted  to  form  a  head  on  it.  There  is  always  some  danger  of  splitting 
a  root  by  screwing  a  post  in  too  tightly. 


CHAPTER  XI. 
THE  TREATMENT  OF  SENSITIVE  DENTIN. 

BY   J.    P.    BUCKLEY,    PH.  G.,  D.  D.  S. 
GENERAL  CONSIDERATIONS. 

It  is  claimed  by  the  best  authorities  that  "in  the  normal  condition 
dentin  should  he  without  sensation;  and  that  the  source  of  sensitive 
dentin,  or  of  impressionable  pulps,  lies  in  their  continued  subjection 
to  irritation  by  which  responsiveness  is  developed"  (Barrett).  This 
view  is,  I  believe,  generally  conceded  to  be  correct  by  all  who  have 
given  this  subject  their  attention.  It  is  true  that  in  the  preparation 
of  cavities  for  fillings  we  find  few  teeth  the  dentin  of  which  is  without 
sensation.  This  fact  is  not  surprising,  nor  can  it  be  construed  as 
being  contrary  to  the  statement  that  normal  dentin  is  not  sensitive, 
when  we  remember  that  there  are  few  teeth  in  the  mouths  of  patients 
demanding  the  services  of  the  dentist,  the  dentinal  fibrillae  and  pulps 
of  which  have  not  been  subjected  to  continued  irritation. 

In  the  discussion  of  means  and  methods  by  which  the  sensitiveness 
of  the  dentin  can  be  allayed  I  shall  not  attempt  to  enter  into  the 
details  of  many  histologic  and  pathologic  phenomena  which  are 
certain  to  arise  in  the  consideration  of  the  therapeutics  of  this  subject; 
but  shall  confine  myself  largely  to  the  drug  aspect. 

It  is  desirable  at  the  outset  that  the  reader  should  understand 
and  appreciate  the  fact  that  there  is  no  other  one  source  of  failure  in 
operative  dentistry  so  great  as  the  improper  preparation  of  the  cavity. 
This  result  does  not  always  follow  because  of  ignorance  on  the  part 
of  the  operator  of  the  principles  involved  in  cavity  preparation,  but 
oftentimes  because  the  patient  will  not  permit,  or  the  operator  does  not 
feel  justified  in  inflicting,  the  pain  necessary  in  carrying  out  those 
principles. 

The  sensitiveness  of  the  dentin  can  be  obtunded  in  no  small  degree 
by  the  use  of  various  therapeutic  agents;  and  I  might  state  that  there 
are  few  operations  which  we  are  called  upon  to  perform  wherein  the 
patient  will  appreciate  our  efforts  more  than  in  this  by  applying  drugs 
and  remedies  for  the  mitigation  of  pain.  But  in  order  to  apply 
intelligently  and  successfully  any  remedy,  whether  it  be  a  drug  or  an 
agent,  to  the  dentin  and  thereby  obtund  the  sensitivity  of  the  dentinal 

219 


220  THE    TREATMENT    OF    SENSITIVE    DENTIN. 

fibrillas  without  endangering  the  vitality  of  the  pulp  itself,  we  must 
be  familiar  with  several  factors  or  conditions,  which  I  cannot  with 
propriety  here  discuss,  in  detail  at  least.  For  instance,  a  thorough 
knowledge  of  the  anatomic  and  histologic  structure  of  the  tooth  is  of 
the  highest  importance,  as  is  also  a  knowledge  of  the  pathology, 
not  only  of  the  fibrillae,  but  of  the  pulp  tissue  as  well — the  changes 
which  these  structures  are  capable  of  undergoing  if  unduly  irritated 
by  the  application  of  the  remedy  employed.  Still  another  factor  of 
equal  importance,  and  one  which  more  directly  relates  to  the  phase  of 
the  subject  under  consideration,  is  a  knowledge  of  the  pharmacologic 
action  and  the  therapeutic  application  of  the  drugs  and  remedies  used 
for  this  purpose. 

The  tendency  in  dentistry  as  well  as  in  medicine  today  is  towards 
rational  therapeutics.  Empirical  methods  of  treatment  are  being 
rapidly  relegated  to  the  past.  Before  using  a  drug  or  an  agent  for 
allaying  the  sensitiveness  of  dentin,  or  for  any  other  purpose,  we 
should  know  what  action  to  anticipate  from  its  employment.  This  is 
not  too  much  to  expect  from  the  trained  dental  practitioner  of  today. 

THERAPEUTICS. 

The  remedies  suggested  for  obtunding  sensitive  dentin  have  been 
many  and  varied.  I  shall  discuss  only  those  which,  from  clinical 
experience,  have  proved  of  sufficient  value  to  merit  consideration; 
and  .for  convenience  of  study,  will  divide  them  into  four  general 
classes. 

I.  Physical  Agents. — Any  agent,  whether  heat,  cold,  light, 
electricity,  or  any  influence  whatever,  if  employed  in  the  treatment 
of  a  diseased  condition,  is  a  remedy.  There  are  some  physical  agents 
by  the  proper  use  of  which  the  sensitiveness  of  dentin  can,  in  a  measure, 
be  obtunded. 

(i)  Heat. — The  application  of  dry  heat  to  a  sensitive  cavity, 
especially  in  conjunction  with  a  dehydrating  agent  such  as  absolute 
alcohol,  is  always  an  aid;  and  this  is  accomplished  by  means  of  heating 
dry  air,  and  gently  directing  a  current  of  air  thus  heated  into  the 
cavity  which  has  been  isolated  by  the  rubber  dam  and  moistened  with 
the  dehydraung  agent  used.  Care  must  be  taken  not  to  primarily 
cause  pain,  otherwise  the  object  of  using  the  agent  would  be  defeated. 

Several  apparatuses  have  been  devised  for  heating  the  air.  Dr. 
Rudolph  Beck,  of  Chicago,  has  recently  perfected  a  convenient  electrical 
device  by  means  of  which  compressed  air  can  be  heated  as  it  passes 
through.     Other  such  devices  are  on  the  market.     The  modern  switch- 


THERAPEUTICS.  221 

board  has  a  heated  air  syringe  as  a  part  of  the  equipment.  In  the 
absence  of  any  of  these  the  chip-blower  can  be  employed;  however, 
with  less  satisfaction.  Inasmuch  as  heat  is  used  in  conjunction  with 
another  and  more  important  class  of  remedies,  I  shall  refer  to  this  agent 
later. 

(2)  Cold. — A  lesser  degree  of  heat,  commonly  designated  coldy 
is  another  physical  agent  sometimes  employed  for  the  purpose  of 
desensitizing  the  dentin.  Heat  may  be  abstracted  from  the  tooth 
structure  by  spraying  the  cavity  with  a  highly  volatile  liquid,  like 
ether,  rhigolene,  or  ethyl  chlorid.  In  the  use  of  these  agents,  advan- 
tage is  taken  of  the  physical  law  that  a  solid  in  changing  its  form  to  a 
liquid,  or  a  liquid  in  changing  its  form  to  a  vapor  or  gas,  must  abstract 
from  the  thing  to  which  it  is  applied,  a  certain  amount  of  heat  in  order 
to  effect  the  change.  Ether,  or  combinations  containing  ether,  and 
ethyl  chlorid,  both  used  as  sprays,  have  proved  valuable  in  some 
instances,  especially  shallow  cavities  near  the  gum  the  dentin  of  which 
is  difficult  to  obtund  by  the  usual  methods  employed,  and  to  which 
reference  will  be  made  later  on  in  this  chapter. 

A  precaution  to  be  taken  to  prevent  primary  pain  in  applying  this 
remedy,  is  to  fill  the  cavity  temporarily  with  stopping,  and  direct  the 
spray  first  on  this  and  surrounding  parts,  after  which  the  stopping  can 
be  removed  and  the  spray  directed  into  cavity  without  any  appreciable 
pain.  The  degree  of  refrigeration  must  not  be  carried  to  the  point 
of  having  a  possible  deleterious  eflfect  subsequently  upon  the  pulp 
or  gum  tissue. 

(3)  Light. — A  form  of  energy  called  light  has  recently  been  brought 
forth  as  having  a  peculiarly  favorable  effect  upon  hypersensitive 
patients.  In  one  method  the  rays  of  light  are  colored  by  passing 
through  a  blue  glass.  This  is  accomplished  by  darkening  the  room 
and  employing  a  blue  bulb  (i6  or  32  c.p.)  on  an  ordinary  electric 
socket.  Whether  the  light  acts  locally,  or  affects  the  vision  and  thus 
the  general  nervous  system,  has  yet  to  be  demonstrated.  The  result 
of  the  author's  experience  with  this  agent  has  not  been  encouraging. 
It  is  true  that  light  differs  in  effect  from  heat,  though  both  come  from 
the  same  heated  body.  This  phenomenon  is  observed  in  the  action  ^ 
of  light  on  certain  chemicals;  for  example,  the  silver  salts,  some  of 
which  are  used  as  obtundents,  undergo  a  chemical  change  when  ex- 
posed to  sunlight  or  luminously  hot  bodies. 

(4)  Electric  Current. — This  agent  has  been  employed  as  a  means 
of  carrying  certain  drugs  into  the  dentin  and  pulp  tissue  for  obtundent 
purposes.     The  method  is  called  cataphoresis;  but  because  of  the 


^ 


222  THE    TREATMENT    OF    SENSITIVE    DENTIN. 

expensive  and  complicated  apparatus,  the  length  of  time  required  to 
obtund  as  well  as  oftentimes  unsatisfactory,  and,  in  not  a  few  instances, 
disastrous  results,  the  method  has  generally  been  discarded. 

II.  Eschar otics  or  Caustics. — Escharotics,  or  caustics,  are  agents 
that  destroy  or  disorganize  the  tissue  upon  which  they  act.  Any 
drug  or  agent,  then,  which  will  cauterize  the  dentinal  fiibrillae,  will 
obtund  sensitive  dentin.  There  are  many  drugs,  however,  belonging 
to  this  class  that  cannot  be  used  for  this  purpose  because  of  their 
deleterious  effect  upon  both  the  tooth  structure  and  the  pulp  tissue. 
For  instance,  the  strong  mineral  acids  will  disorganize  the  protoplasmic 
dentinal  fibrillae;  but  they  will  also  disintegrate  the  inorganic  structure 
of  the  tooth.  Arsenic  trioxid  has  a  specific  poisonous  action  upon  the 
fibrillae,  but  there  is  no  known  means  of  preventing  the  same  deleterious 
effect  upon  the  cells  of  the  pulp  tissue. 

The  most  valuable  escharotics  for  desensitizing  the  dentin  are: 

Phenol,  Trichloracetic  acid. 

Zinc  chlorid.  Silver  nitrate. 

It  must  be  noted  that,  while  these  agents  will  obtund,  the  ultimate 
result  is  too  often  produced,  with  the  possible  exception  of  phenol, 
at  the  expense  of  quite  as  much  suffering  as  they  save. 

Phenol  has  local  analgesic  properties  besides  that  of  cauterant, 
and  will,  therefore,  be  discussed  under  another  and  more  important 
class  of  agents. 

Zinc  chlorid  in  various  strength  solutions  can  be  used  to  advantage 
in  a  class  of  cavities  where  the  decay  or  softened  dentin  does  not 
extend  too  close  to  the  pulp.  Zinc  chlorid  coagulates  albumin  and 
in  the  process  hydrochloric  acid  is  liberated.  For  this  reason  the 
application  of  strong  solutions  is  painful  and  should  not  be  employed 
in  deep  cavities  unless  the  irritating  action  of  the  agent  is  modified. 
This  can  be  done  to  a  marked  degree  by  selecting  alcohol  and  chloro- 
form as  the  vehicle  in  which  to  make  the  solution. 

A  useful  formula  is  here  given : 

I^ — Zinci  chloridi,  gr.     xx 

Alcoholis,  f.  5  iv 

Chloroformi,  q.  s.  ad.  f.  §  j     — M. 

Sig. — Apply  to  the  cavity  on  a  small  pledget  of 
cotton  and  gently  evaporate  to  dryness. 

Note:  If  the  zinc  salt  does  not  make  a  clear 
solution  in  the  alcohol  it  indicates  that 
some  of  the  salt  has  been  oxidized;  the 
solution  can  be  cleared  by  adding  one 
drop  of  hydrochloric  acid. 


THERAPEUTICS .  2  2  3 

This  remedy  is  a  disinfectant  and  it  has  the  added  advantage  of 
sterilizing  the  dentin  at  the  same  time  that  it  produces  its  obtundent 
effect. 

Trichloracetic  acid  in  concentrated  solution  causes  considerable 
pain  when  first  applied  to  a  sensitive  cavity,  therefore  defeating  the 
object  of  its  use;  but  in  a  lo  or  15  per  cent  solution  it  produces  but 
little  pain  or  inflammatory  reaction.  In  this  strength  it  can  be  em- 
ployed; but  not  always  with  satisfactory  results. 

Silver  nitrate  is  perhaps  the  only  known  prophylactic  for  decay. 
In  the  posterior  part  of  the  mouth  where  the  cementum  is  exposed 
to  external  influences  and  thus  sensitive,  or  in  shallow  cavities,  especi- 
ally in  children's  teeth,  the  use  of  this  drug,  in  the  solid  pencil  form 
or  in  various  strength  solutions,  will  be  found  valuable,  both  as  a 
means  of  reducing  the  sensitiveness  and  preventing  further  ingress  of 
caries.  As  an  agent  for  obtunding  the  sensitivity  of  the  dentin  in  an 
ordinary  cavity,  it  should  not  be  considered  for  various  reasons. 
When  the  agent  is  employed  for  the  purposes  above  mentioned,  the 
cavity,  after  the  application,  should  be  kept  free  from  saliva  for  a 
few  minutes,  and,  if  possible,  exposed  to  sunlight,  thus  decomposing 
the  silver  salt  as  referred  to  in  this  chapter  under  the  subject  of  light. 
In  the  absence  of  sunlight,  a  practical  means  of  decomposing  the  salt  is 
by  the  use  of  the  electric  mouth  lamp.  A  solution  of  sodium  chlorid 
should  always  be  at  hand  when  using  silver  nitrate,  and  in  case  any  of 
the  latter  agent  should  accidentally  get  on  the  mucous  membrane  of  the 
patient's  mouth  its  action  can  be  checked  at  once  by  rinsing  the  mouth 
with  this  antidotal  solution. 

III.  Local  Anodynes  or  Local  Anesthetics. — A  local  anodyne  is 
an  agent  which,  when  applied  to  a  part,  relieves  pain.  A  local  anes- 
thetic is  an  agent  which,  when  applied,  produces  insensibility  to  pain 
in  that  particular  locality.  According  to  Long,  it  rather  produces  a 
condition  of  analgesia,  which  means  the  absence  of  sensibility  to  pain, 
as  distinguished  from  true  anesthesia,  the  absence  of  all  sensibility. 

In  the  judicious  use  of  agents  belonging  to  this  class  the  author 

firmly  believes  will  ultimately  be  found  the  surest  and  safest  road  to 

success.     The  following  agents,  or  a  combination  of  two  or  more, 

will  be  found  to  be  of  the  utmost  importance: 

Cocain,  Phenol, 

Menthol,  Ethyl  chlorid, 

Oil  of  cloves,  Ether, 

Eugenol,  Chloroform. 

Cocain  is  one  of  several  alkaloids,  this  being  by  far  the  most  im- 
portant,  obtained   from  the  leaves  of  Erythroxylon   Coca,   a  plant 


224  THE   TREATMENT    OF    SENSITIVE    DENTIN. 

indigenous  to  Peru  and  other  South  American  states.  Both  the 
alkaloid,  cocain,  and  the  alkaloidal  salt,  cocain  hydrochlorid,  are 
used  in  various  ways  for  obtunding  sensitive  dentin.  The  alkaloidal 
salt  was  formerly  recognized  by  the  United  States  Pharmacopeia  as 
cocain  hydrochlorate ;  but  in  the  last  edition  (1900)  it  is  called  cocain 
hydrochlorid.  An  important  physiologic  property  of  cocain  to  be 
remembered  here,  is  its  power,  when  applied  directly  to  the  mucous 
membrane  or  when  injected  or  forced  into  the  pulp  tissue,  of  inducing 
a  condition  of  analgesia  in  the  part  by  paralyzing  the  sensory  nerve 
filaments.  In  addition  to  this  it  causes  a  blanching  of  the  part  which 
is  subsequently  followed  by  congestion.  It  should  also  be  remembered 
that  pharmacologists  have  proved,  beyond  a  doubt,  that  cocain  is  a 
general  protoplasmic  poison;  that  muscles  as  well  as  nerves  and  nerve- 
ends  cease  to  contract  or  to  conduct  stimuli  when  they  are  exposed 
to  even  dilute  solutions  of  the  drug.  The  only  reason  that  the  delete- 
rious effect  is  more  noticeable  upon  nerve  than  upon  other  kinds  of 
tissue  is  that  here  we  are  dealing  with  the  medium  of  sensation  and 
expression. 

The  author  deems  it  wise  to  call  attention  to  these  well-established 
physiologic,  pharmacologic  and  pathologic  facts,  for  many  instruments 
have  recently  been  devised  for  forcing  various  strength  solutions  of 
cocain  hydrochlorid,  not  only  into  the  dentinal  tubuli,  thereby  para- 
lyzing the  fibrillae,  but  into  the  pulp  proper,  anesthetizing  this  organ  as 
well.  In  view  of  these  facts  it  would  appear  that  we  are  seldom,  if  ever, 
justified  in  completely  anesthetizing  the  pulp  of  a  tooth  for  the  purpose 
of  painlessly  preparing  a  cavity  therein.  Therefore  under  the  subject  of 
cataphoresis  in  this  chapter,  little  was  written;  and  for  the  same  rea- 
sons, the  method  of  anesthetizing  the  pulp  by  high  pressure  anesthesia, 
for  obtundent  purposes  only,  will  not  be  considered.  Both  of  these 
methods  will  be  discussed  in  a  subsequent  chapter  on  pulp  removal. 

Cocain  and  the  alkaloidal  salt,  cocain  hydrochlorid,  are  safe  and 
valuable  agents  for  obtunding  sensitive  dentin,  if  confined  to  the 
dentinal  structure  of  the  tooth.  Frequently  in  deep-seated  cavities, 
especially  in  children's  teeth,  the  sensitiveness  can  be  completely 
overcome  by  sealing  in  the  cavity  for  a  day  or  two  a  qreamy  paste 
made  by  mixing  the  alkaloid  cocain  with  liquid  petroleum.  The 
revised  edition  of  the  United  States  Pharmacopeia  now  recognizes  an 
oleate  of  cocain  (5  per  cent),  which  can  be  used  for  this  purpose.  The 
paste  or  oleate  should  cover  the  entire  surface  of  dentin  which  we  sub- 
sequently expect  to  excavate.  Good  results  can  also  be  immediately 
obtained  by  the  us  ■  of  the  following  remedy: 


THERAPEUTICS.  225 

I^ — Cocainae,  gr.  xx 

Chloroformi,  f.  3  ij 

Etheris,  q.  s.  ad,  f.  5  j  -M. 

Sig. — After  the  rubber  dam  has  been  adjusted, 
apply  to  the  cavity  on  a  small  pledget  of 
cotton  and  evaporate  to  dryness. 

In  the  use  of  this  remedy,  advantage  is  taken  of  the  physical  law 
previously  referred  to  in  this  chapter  under  cold.  As  the  volatile 
liquids,  ether  and  chloroform,  evaporate,  a  certain  amount  of  heat 
is  abstracted  from  the  tooth  structure,  and  a  coating  of  the  alkaloid, 
driven  to  an  extent  into  the  dentin,  is  left  in  the  cavity.  This  remedy 
will  not  completely  obtund  all  sensitive  dentin,  but  its  use  will  be  a 
material  'aid. 

There  can  be  no  objection  in  favorable  cases,  provided  the  dentin 
has  been  previously  sterilized,  to  using  aqueous  solutions  of  cocain 
hydrochlorid  with  uniform  pressure  over  the  entire  area  of  the  cavity, 
thus  forcing  the  anesthetizing  solution  an  equal  distance  into  the 
dentin.  This  is  an  extremely  difficult  thing  to  do  without  forcing  the 
solution  at  some  more  favorable  point  in  the  cavity  through  the  tubuli 
and  into  the  pulp.  However,  there  are  cavities  where  good  results 
can  be  accomplished  by  the  careful  use  of  this  method.  In  some 
cases  of  gingival  cavities  good  results  can  be  obtained  by  hypoder- 
mically  injecting  a  i  or  1.5  per  cent  solution  of  cocain  hydrochlorid 
into  the  pericemental  membrane  somewhere  near  the  apex  of  the 
root.     This  practice  should  not  be  generally  recommended. 

Menthol,  a  stearopten  obtained  from  the  essential  oil  of  pepper- 
mint, can  be  substituted  for  the  cocain  in  the  above  prescription  with 
ether  and  chloroform,  and  used  in  exactly  the  same  manner.  An 
oily  liquid  (mentho-chloral)  can  be  formed  by  heating  together  over 
a  water-bath  or  rubbing  in  a  mortar,  an  equal  amount  of  menthol 
and  chloral.  This  remedy  will  be  found  efl&cacious  by  sealing  in  the 
cavity  for  a  few  days. 

f  Oil  of  Cloves. — A  profound  analgesic  effect  can  be  produced  upon 
sensitive  dentin,  especially  in  deep-seated  cavities,  by  using  oil  of 
cloves  and  heat  in  the  following  manner:  After  carefully  desiccating 
the  dentin  by  means  of  warm  alcohol  and  gentle  heat,  a  pledget  of 
cotton  saturated  with  oil  of  cloves  should  be  placed  in  the  cavity  and 
a  current  of  heated  dry  air  directed  thereon  until  the  cotton  is  nearly 
dry.     This  should  be  repeated  as  often  as  the  case  demands. 

Eugenol,  an  oily  product,  is  the  chief  constituent  of  oil  of  cloves 
and  can  be  used  in  the  same  manner  as  above  described. 

Phenol. — It  is  gratifying  to  the  author  to  know  that  in  the  last 
IS 


226  THE    TREATMENT    OF    SENSITIVE    DENTIN. 

revision  of  United  States  Pharmacopeia  (1900),  the  publication  of 
which  appeared  Sept.  i,  1905,  the  product  heretofore  erroneously 
'called  carbolic  acid  has  been  recognized  by  its  correct  name,  phenol. 
This  agent  can  be  substituted,  with  equally  good  results,  for  the  oil 
of  cloves  or  eugenol  as  described  in  the  foregoing  method.  Care 
should  be  taken  here,  however,  in  directing  the  heated  air  so  as  not  to 
cause  the  fumes  of  phenol  to  escape  on  the  patient's  face.  Oil  of 
cloves,  eugenol  and  phenol  are  three  true  local  anodynes,  and  any  one 
of  which,  if  hermetically  sealed  in  a  cavity  for  a  few  weeks,  will  check 
the  continued  irritation  of  the  fibrillae  and  pulp,  thus  aiding  nature 
to  restore  these  structures  to  their  normal  condition  when  they  should 
not  be  responsive.  By  this  means,  then,  the  sensitiveness  of  the 
dentin  can  also  be  allayed. 

Ethyl  chlorid,  ether  and  chloroform,  by  their  rapid  volatility, 
produce  a  condition  of  analgesia,  thereby  obtunding  sensitive  dentin, 
as  previously  explained  in  this  chapter  under  cold. 

IV.  General  Anodynes  or  Analgesics. — General  anodynes  or  anal- 
gesics are  remedies  which  relieve  pain  without  necessarily  inducing 
■  unconsciousness  or  general  anesthesia.  They  may  accomplish  their 
object  by  acting  upon  the  perceptive  centers  of  the  brain,  the  afferent 
paths  in  the  spinal  cord,  or  the  peripheral  nerve  through  which  the 
painful  impression  is  transmitted   (Stevens). 

In  order  to  do  permanent  work  for  certain  highly  nervous  patients, 
it  is  sometimes  necessary  to  resort  to  the  administration  of  this  class 
of  drugs.     The  agents  largely  used  for  this  purpose  are: 

Opium.  Nitrous  oxid. 

The  bromids,  Chloroform. 

Opium  is  a  most  powerful  analgesic,  and  while  there  are  some 
dental  conditions  where  this  drug,  or  its  chief  alkaloid,  morphin,  is 
truly  indicated,  it  ought  not,  in  the  author's  judgment,  to  be  given  for 
the  treatment  of  sensitive  dentin. 

The  bromids  of  potassium,  sodium  and  ammonium  are  valuable 
drugs  in  certain  cases.  Perhaps  there  is  no  drug  which  will  quiet 
a  nervous  patient  more  readily,  when  the  nervousness  comes  purely 
from  fear  or  dread,  than  potassium  bromid,  which  is  the  represen- 
tative of  this  class.  In  such  cases,  where  it  is  deemed  necessary,  the 
following  prescription  will  prove  helpful: 

I^ — Potassii  bromidi,  5  jss 

Syrupi  sarsaparillae  comp.,  f.5  iij — M. 

Sig. — Take  a  tablespoonful  in  water  after  meals  the 
day  before  coming  to  the  office. 


THERAPEUTICS.  227 

Nitrous  Oxid. — There  are  several  apparatuses  on  the  market 
by  which  nitrous  oxid  gas  can  be  administered  through  the  nose. 
With  the  newer  and  improved  gas  outfits  oxygen  can  be  mixed  with 
nitrous  oxid  in  varying  proportions,  as  the  case  demands.  It  is  possible 
with  such  an  apparatus  to  carry  the  patient  just  to  the  analgesic  stage, 
and  hold  him  there  indefinitely  until  a  sensitive  cavity  has  been  pain- 
lessly prepared.  In  cases  where  the  operator  feels  that  it  is  necessary 
to  resort  to  this  method,  good  results  can  be  accomplished. 

Chloroform. — With  the  patient  in  the  upright  position,  chloroform 
can  be  carried  to  the  analgesic  stage  and  sensitive  cavities  prepared. 
Most  authorities  agree,  however,  that  chloroform  should  not  be 
administered  unless  the  patient  is  in  the  recumbent  position,  and  that 
the  analgesic  stage  is  the  most  dangerous.  Death  has  been  known 
to  occur  suddenly,  after  a  few  inhalations,  in  cases  of  marked  idio- 
syncrasy against  the  drug. 

The  author  would  not  suggest  the  use  of  chloroform  for  this 
purpose. 

In  closing  this  chapter,  may  I  say  that  most  patients  who  repose 
confidence  in  the  operator,  are  sensible  and  are  willing  to  stand  some 
pain  in  the  preparation  of  cavities  in  their  teeth.  When  preparing  a 
cavity  for  a  filling  in  a  tooth,  the  pulp  of  which  is  vital,  and  where  it 
is  the  intention  to  maintain  this  organ  in  a  healthy  condition,  pain  should 
be  our  indicator  and  our  guide.  With  a  true  running  engine,  a  steady 
hand,  a  sharp  bur,  and  with  the  aid  of  some  of  the  many  remedies  herein 
suggested,  the  operator  ought  not  to  expect  nor  to  ask  the  patient  to 
stand  more  than  a  small  amount  of  pain  in  the  preparation  of  the  most 
sensitive  cavity. 


CHAPTER  XII. 

FILLING    MATERIALS:    THEIR    CHARACTERISTICS, 

INDICATIONS  FOR  THEIR  USE  AND  THE 

METHODS  OF  MANIPULATION. 

BY  ALFRED  OWRE,  B.A.,  M.  D.,  CM.,  D.  M.  D. 

The  dentist  of  today  is,  perhaps,  more  occupied  with  the  treat- 
ment of  caries,  both  in  theory  and  in  practice,  than  with  any  other 
branch  of  his  profession.  Although  we  recognize,  in  the  prevalent 
custom  of  treatment  by  filling,  only  a  provisional  substitute  for  some 
more  nearly  perfect  one  at  which,  in  our  present  stage  of  development, 
we  have  not  yet  arrived,  it  behooves  us,  until  we  shall  have  outgrown 
it,  to  study  closely  its  methods  and  materials. 

In  the  discussion  of  materials  we  are  confronted  by  the  fact  that 
in  the  very  nature  of  things  there  can  be  no  one  substance  suited  to  all 
cases.  There  is,  however,  for  every  case  a  suitable  material,  or  one 
which  can  be  continued  in  use  as  such  until,  in  our  pursuit  of  the  ideal, 
we  progress  to  something  more  efifective. 

To  acquire  the  art  of  filling  teeth  seems  at  the  outset  an  Alpine 
task.  A  thorough  understanding  of  the  properties  of  various  neces- 
sary materials  will  reduce  difficulties  immensely,  just  as  in  setting  out 
for  a  long  climb  in  the  mountains  the  providing  of  guides  and  the 
study  of  maps  will  reduce  distances  and  minimize  dangers. 

It  will  be  the  aim  of  this  chapter  to  point  out  as  clearly  as  possible 
the  teleological  value  and  characteristic  properties  of  gold,  amalgam, 
tin,  cement,  and  gutta-percha.  We  shall  try  to  suggest  when  and 
where  to  apply  these  materials  in  filling  cavities  of  teeth  to  insure 
the  highest  degree  of  success;  and  also  to  describe  the  methods  of  prep- 
aration, insertion,  and  finish. 

GOLD. 

From  the  earliest  days  of  dental  surgery,  gold  seems  to  have  been 
considered  the  filling  material  par  excellence.  It  occupies  a  unique 
prominence  in  operative  dentistry.  The  ancient  uses  to  which  it  was 
put  for  royal  and  religious  ornament  rendered  its  more  common  prop- 
erties familiar  to  the  metal-workers  of  even  prehistoric  times.  The 
greedy,  but  persistent,  alchemists  of  mediaeval  laboratories  have  con- 
tributed to  modern  science  the  results  of  their  research  for  "thephilos- 

229 


230  FILLING    MATERIALS. 

opher's  stone."  Gold  has  had,  therefore,  one  great  advantage — 
that  of  familiarity — over  the  later  filling  materials  whose  properties 
were  little  known  and  in  whose  actions  scientists  were  slow  to  become 
interested. 

The  appeal  of  gold,  to  primitive  man,  inhered  in  its  peculiar 
combination  of  luster  and  yellow  color.  This  color  is  deepened  or 
raised  in  tone  by  the  introduction  of  foreign  substances,  copper  for 
the  former  purpose,  and  silver  for  the  latter.  In  allotropic  form 
it  is  susceptible  of  alteration  to  other  than  the  original  color.  When 
reduced  to  a  finely  divided  state  by  precipitation,  violet,  dark  red, 
purple,  brown,  and  even  black  may  be  produced.  However,  when 
burnished  or  fused,  it  again  assumes  its  characteristic  yellow  color. 

Another  peculiar  property  of  gold  is  its  extreme  malleability. 
In  this  respect  it  exceeds  all  other  metals.  It  can  be  reduced  by 
beating  to  3  -^  q^q  ^  ^  of  an  inch  in  thickness.  It  also  heads  the  list  in 
ductility.  A  single  grain  may  be  drawn  out  into  a  wire  over  five 
hundred  feet  in  length.  Both  of  these  properties  are  modified  or  ren- 
dered nil  by  alloying. 

As  to  the  property  of  hardness,  gold,  when  pure,  lies  between 
silver  and  aluminum.  It  is  about  one-third  as  hard  as  diamond. 
This  property  is  generally  increased  by  the  presence  of  alloys,  extremely 
small  quantities  of  some  elements  (bismuth,  lead,  etc.)  having  a  very 
marked  effect,  even  to  rendering  the  metal  capable  of  pulverization 
in  a  mortar. 

As  regards  tenacity,  pure  gold  will  hold  a  weight  of  seven  tons  per 
square  inch.  This  property,  also,  is  reduced  by  the  presence  of  im- 
purities. 

The  specific  gravity  of  cast  gold  is  19.3,  which  can  be  increased  by 
condensation.  In  some  of  its  precipitated  forms  it  may  be  as  high 
as  20.3.  The  difference  is  accounted  for  by  the  annealing  in  the  for- 
mer case. 

In  general,  gold  is  weldable  in  the  cold  state  in  proportion  to  its 
purity;  a  very  minute  trace,  i  in  1000,  of  foreign  metal  such  as  silver, 
copper,  or  platinum,  is  said  not  noticeably  to  interfere  with  its  cohesive- 
ness.     This  property  is  usually  increased  by  heating. 

The  presence  of  other  metals  alloyed  with  gold  renders  it  more 
susceptible  to  the  occlusion  of  obnoxious  gases.  The  cohesive  power 
is  decidedly  lessened  by  surface  gases  such  as  ammonia,  hydrogen, 
hydrogen  phosphide,  and  sulphurous  acid  gas,  all  of  which  are  at- 
tracted to  pure  gold,  but  to  a  greater  degree  when  the  metal  is  finely 
divided  than  when  it  is  cast. 


GOLD.  231 

In  the  scale  of  conductivity,  with  silver  first,  at  1000  for  both  heat 
and  electricity,  copper  is  second,  and  gold  third  with  a  register  of  548 
for  heat,  and  730  for  electricity. 

Its  solubility  is  proved  in  aqua  regia  and  in  mixtures  producing 
nascent  chlorine,  bromine,  and,  under  certain  conditions,  iodine. 

The  consideration  of  the  qualities  essential  to  a  good  filling  ma- 
terial is  a  very  important  one.  According  to  Dr.  G.  V.  Black,  the 
chief  qualities  are: 

Indestructibility  in  the  fluids  of  the  mouth.  Adaptability  to  cavity 
walls.  Freedom  from  shrinkage  or  expansion  after  having  been 
made  into  fillings.  Resistance  to  attrition  and  the  force  of  mastic- 
ation. Of  secondary  importance  are  color,  non-conductivity  of  ther- 
mal impressions,  and  convenience  of  manipulation.  It  should  also 
be  capable  of  receiving  a  polish. 

Bearing  its  constant  properties  in  mind,  let  us  see  how  gold  fulfills 
these  requirements. 

There  can  be  no  question  as  to  its  indestructibility  in  the  fluids  of 
the  mouth;  although  iodine  discolors  it  somewhat,  it  does  not  cause 
solution.  It  is  highly  capable  of  adaptation  to  cavity  walls.  There 
is  neither  shrinkage  nor  expansion;  but  the  intermittent  forces  of  mas- 
tication may  work,  together  with  the  peculiar  molecular  structures, 
to  produce  some  change  in  form.  The  yeflow  color  and  high  burnish, 
so  beautiful  in  themselves,  are,  as  fillings,  more  or  less  of  an  objection 
from  the  esthetic  viewpoint.  The  contrast  in  color  between  the  gold 
and  the  enamel  may  be  rendered  less  noticeable  by  attention  to  the 
outline  form  of  the  cavity.  An  outline  may  be  varied  for  the  sa»ke  of 
grace,  without  hindering  the  achievement  of  artistic  results,  bearing 
in  mind,  of  course,  that  the  application  of  gold  is  not,  primarily, 
assumed  to  be  inartistic.  Conductivity  is  a  decidedly  unfavorable 
property.  In  regard  to  the  manipulation  of  gold,  we  may  say  that, 
in  general,  it  is  difiicult,  and  demands  sustained  effort.  It  is  generally 
acknowledged  that  success  with  this  material  exacts  close  application 
and  prolonged  study.  As  to  finish,  a  perfect  surface  depends  only 
upon  the  gold  being  reasonably  well  condensed. 

As  to  the  use  of  gold,  it  is  not  easy  to  lay  down  set  laws.  When 
and  where  to  apply  it  depend  upon  a  close  study  of  general  conditions 
and  upon  the  extent  to  which  the  operator's  instinct  for  the  eternal 
fitness  of  things  has  been  cultivated.  No  aspect  of  dentistry  demands 
keener  judgment  and  finer  appreciation  of  practical  and  esthetic 
values.  Moreover,  the  physical  condition  and  idiosyncrasies  of  the 
patient  constitute  a  large  factor  in  the  problem.     The  age  and  state 


232  FILLING    MATERIALS. 

of  health,  both  general  and  local,  must  be  taken  into  consideration. 
Mental  traits,  as  well,  will  be  weighed  by  the  tactful  dentist,  since  the 
immature  mind,  and  that  which  is  under  imperfect  nervous  control, 
must  be  met  with  special  resources. 

It  must  be  borne  in  mind  that  in  man  as  in  other  animals  the  period 
of  plasticity  is  the  age  of  education.  Organization  and  education, 
physical  and  mental,  have  sometimes  reached  a  stage  of  balance  early 
in  life.  When  this  happens,  rather  extensive  gold  fillings  may  be  made 
for  patients  between  the  ages  of  ten  and  sixteen  years. 

Between  twelve  and  eighteen,  the  age  of  adolescence,  the  powers 
of  the  body  develop  at  a  lower  rate  than  those  of  the  mind;  and  it 
would  be  unwise  to  attempt  the  insertion  of  large  gold  jBllings  unless 
the  entire  system  of  the  patient  be  adequate  to  the  strain. 

As  the  patient  advances  in  years,  the  physical  and  nervous  re- 
sistance must  not  cease  to  be  a  matter  of  careful  consideration.  If 
this  resistance  be  below  par,  or  if  all  extra  energy  be  needed  to  nurse 
some  disorder,  it  is  best  to  postpone  large  gold  operations. 

Locally  we  have  many  things  to  consider,  such  as  conditions  of 
the  peridental  membrane,  the  extent  and  acuteness  of  decay,  the 
structure  and  strength  of  cavity  walls,  occlusion,  wear  and  tear,  the 
position  of  the  tooth,  accessibility,  and  possibly  also  the  past  hygiene 
and  care  of  the  mouth. 

It  is  quite  needless  to  say  that  no  gold  filling  should  ever  be  at- 
tempted in  any  tooth  when  there  is  manifest  pericemental  inflammation. 
The  slight  loosening  of  the  tooth  as  a  result  of  deposits,  or  of  wear  and 
tear,  need  not  prohibit  the  insertion  of  gold;  but  if  any  great  degree  of 
loosening  has  taken  place,  gold  is  generally  contra-indicated.  Whether 
the  membrane  is  abnormal  or  not,  its  resistance  should  be  a  guide. 
If  caries  is  rampant,  it  is  often  advisable  not  to  consider  gold  until 
more  favorable  conditions,  or  a  period  of  immunity,  ensue. 

The  firmness  of  the  cavity  walls  may  be  insufficient  to  withstand 
the  force  necessary  for  the  proper  introduction  of  gold,  especially 
if  the  strength  of  the  bite  is  in  the  neighborhood  of  175  pounds.  Many 
malleted  gold  fillings  fail  in  strong  occlusions.  They  may  also  fail 
where  the  area  of  masticating  surface  has  been  lessened  by  extractions 
of  molar  teeth.  In  this  latter  case,  it  often  occurs  that  proximo- 
incisal  fillings  have  been  literally  pounded  out,  owing  to  the  excess  of 
work  performed  by  the  anterior  teeth. 

In  regard  to  position,  the  tooth  may  be  inclined  to  such  a  degree 
as  to  render  gold  difficult  to  insert,  and,  in  consequence,  preferably 
omitted. 


GOLD.  233 

The  use  of  gold  need  not  be  restricted  to  any  particular  teeth,  for 
instance,  as  has  been  often  suggested,  to  the  ten  anterior  teeth.  It 
would  be  more  scientific,  and  decidedly  more  practical  to  say  that, 
other  things  being  equal,  we  can  use  it  wherever  there  is  sufficient 
accessibility.     So  far,  then,  it  becomes  the  ideal. 

Much  has  been  said  about  this  material.  In  fact,  it  would  seem 
that  nothing  more  remains  to  be  said  either  for  or  against  it.  When 
we  consider  that  the  future  preservation  of  the  teeth  depends  upon 
the  extent  to  which  recurrence  of  caries  can  be  prevented,  and  normal 
conditions  and  functions  otherwise  restored,  we  naturally  seek  a  fill- 
ing material  which  will  as  much  as  possible  further  these  aims. 
Statistics  have  been  published  showing  that  the  average  life  of  a  gold 
filling  is  three  years.  Just  so  long  as  gold  is  used  indiscriminately, 
and  by  all  kinds  of  operators,  will  we  have  such  figures. 

But  these  are  not  the  statistics  by  which  we  wish  to  be  influenced 
It  debases  our  own  standards,  and  works  injustice  to  the  best  men  in 
the  profession  of  dentistry — those  who  are  most  influential,  and  who 
make  up  a  very  large  proportion  of  the  total  number — to  obscure  their 
results  by  fusing  with  them  the  results  of  the  incapable,  and  then  strik- 
ing an  average.  Such  statistics  are  misleading.  It  would  be  much 
more  to  the  purpose  to  take  account  only  of  those  men  who  are  pre- 
eminently fitted  to  practice  dentistry.  Such  men  are  honest  enough 
to  acknowledge  failures  wherever  they  occur,  and  if  data  were  gathered 
exclusively  from  them,  some  reliable  figures  would  exist  upon  which 
changes  could  be  based  when  it  is  found  that  the  percentage  of  failures 
is  becoming  too  high. 

Not  to  go  any  further  with  this  discussion,  we  may,  for  the  moment, 
rest  upon  the  statement  that  success  hinges  upon  careful  judgment 
in  the  selection  of  cases,  as  well  as  upon  manipulation  or  technique 
of  insertion  and  finish. 

In  all  discussions  of  the  subject,  so  much  is  said  as  to  the  impor- 
tance of  purity  in  gold,  that  it  has  been  thought  best  to  quote  in  full  the 
Roberts-Austen  refining  process  as  given  in  Rose's  The  Metallurgy 
0}  Gold: 

Gold  assay  cornets,  from  the  purest  gold  which  can  be  obtained,  are  dis- 
solved in  nitrohydrochloric  acid,  the  excess  of  acid  expelled,  and  alcohol 
and  chloride  of  potassium  added  to  precipitate  traces  of  platinum.  The 
chloride  of  gold  is  then  dissolved  in  distilled  water  in  the  proportion  of 
about  half  an  ounce  of  the  metal  to  one  gallon,  and  the  solution  allowed 
to  stand  for  three  weeks.  At  the  end  of  this  time  the  whole  of  the  pre- 
cipitated silver  chloride  will  have  subsided  to  the  bottom,  and  the  super- 


234  FILLING    MATERIALS. 

natant  liquid  is  removed  by  a  glass  siphon.  Crystals  of  oxalic  acid  are 
then  added  from  time  to  time,  and  the  liquid  gendy  warmed  until  it  be- 
comes colorless,  when  precipitation  is  complete,  a  point  reached  in  three 
or  four  days  if  ten-gallon  vessels  are  used.  The  spongy  and  scaly  gold 
so  obtained  is  washed  repeatedly  with  hydrochloric  acid,  distilled  water, 
ammonia,  and  distilled  water  again,  until  no  reaction  for  silver  or  chlo- 
rine can  be  obtained,  after  which  it  is  melted  into  a  clay  crucible  with 
bisulphate  of  potash  and  borax,  and  poured  into  a  stone  mold.  Lack 
of  care  in  any  one  of  the  operations  will  result  in  gold  containing  one  or 
two  parts  of  impurity  in  ten  thousand. 

If  further  purity  is  desired,  the  gold  may  be  redissolved  and  re- 
precipitated  until  satisfaction  is  attained. 

Gold  comes  to  us  from  the  manufacturer  in  two  varieties,  foils 
and  crystals.  A  complete  description  of  the  manufacture  of  foil  oc- 
curs in  an  article  entitled  "Gold  Beating"  in  the  Encyclopedia  Brit- 
tanica. 

The  sheets  are  usually  four  inches  square,  and  the  number  by  which 
each  one  is  identified  corresponds  to  the  number  of  grains  in  the  sheet; 
e.g.,  in  No.  4  foil  each  sheet  weighs  4  grs.,  and  so  on  up  to  No.  100, 
or  higher.  Above  No.  20,  the  sheets  are  rolled  out  instead  of  beaten. 
They  may  be  had  smooth  or  corrugated. 

Foils  may  be  classified  according  as  they  lack  or  possess  the  property 
of  cohesion.  They  are  non-cohesive,  semicohesive,  or  cohesive. 
Non-cohesive  gold  is  made  so  by  surface  treatment,  and  although  the 
process  is  not  made  public,  we  know  that  we  can  render  pure  gold  non- 
cohesive  by  exposing  it  to  ammoniacal  gas.*  The  semicohesive  golds, 
and  some  of  the  non-cohesive,  can  be  made  cohesive  by  annealing, 
which  demonstrates  that  surface  treatment  had  consisted,  in  this  in- 
stance, of  subjection  to  a  volatile  gas. 

Some  non-cohesive  foils  are  permanently  so,  and  the  gases  covering 
the  surface  are  probably  of  the  sulphur  or  phosphor  groups,  which  can- 
not be  volatilized  by  heat,  but  condense  upon  the  surface. 

Foil  has  been  used  for  about  a  century,  chiefly  in  a  non-cohesive 
state.  The  discovery  of  its  cohesive  property,  about  fifty  years  ago, 
marks  an  era  in  the  history  of  operative  dentistry.  It  has  made  con- 
tour possible  in  its  broadest  sense,  and  the  resulting  advances  are  of 
tremendous  importance.  That  the  possibilities  are  not  yet  exhausted 
is  another  point  which  should  encourage  the  profession  towards 
progress. 

The  crystals  of  gold  are  obtained  by  precipitation.  The  manufac- 
*Dr.  G  V  Black.  Dental  Cosmos,  Vol.  17. 


GOLD.  235 

turers  guard  their  trade  secrets  so  well  that  we  do  not  know  what  pre- 
cipitating agent  is  used.  Oxalic  acid,  purified  sulphurous  acid  gas, 
and  other  chemical  reagents  can  be  used,  but  at  present  these  are  largely 
replaced  by  electrolytic  methods.  There  are  on  the  market  several 
variations  of  these  forms,  of  which  the  fiber-like  crystals  are  generally 
to  be  preferred.  It  is  very  probable  that  the  crystals  have  a  higher 
specific  gravity,  since  they  have  never  been  subjected  to  fusion.  They 
are  usually  sold  in  the  cohesive  state.  Among  qualities  decidedly  in 
their  favor  is  a  plasticity  which  renders  them  easy  to  manipulate. 

There  has  been,  and  still  is,  some  prejudice  against  gold  in  this 
form,  owing  to  a  variable  quality  which  can  be  accounted  for,  in  a 
measure,  by  the  fact  that  crystals  are  more  easily  contaminated. 

Although  methods  of  preparation  have  been  more  or  less  faulty 
in  the  past,  modern  methods  have  given  us  a  fairly  rehable  product, 
with  the  result  that  crystals  have  increased  in  use. 

The  dentist  should  procure  a  gold  which  is  experimentally  known 
for  its  good  qualities;  but  he  must  always  be  on  the  lookout  lest  un- 
scrupulous manufacturers  permit  deterioration. 

There  is  a  variety  of  ways  in  which  the  dentist  can  shape  foil  as 
wanted,  and  to  suit  the  various  cavities:  the  ribbon,  mat,  cylinder, 
pellet,  or  rope.  In  some  of  these  shapes  it  can  be  bought  ready 
prepared. 

The  ribbon  is  formed  by  taking  as  much  as  is  required  of  a  sheet 
of  gold  and,  by  repeated  folding,  reducing  it  to  the  desired  width. 
The  mat  is  made  by  simply  folding  the  width  of  the  ribbon  upon  itself 
according  to  size  wanted;  cylinders,  by  rolling  the  ribbon  upon  a  flat 
broach.  The  pellet  may  represent  from  ^  of  a  sheet  upwards,  rolled 
to  a  loose  ball  between  the  ends  of  the  fingers.  The  ropes  or  rolls  are 
made  by  rolling  a  part  of  the  sheet  between  the  thumb  and  forefinger, 
or  between  two  napkins.  The  heavier  foils  need  only  to  be  cut  into 
strips  of  suitable  size. 

Dr.  Black  recommends  keeping  the  gold  in  a  compartment  where 
ammonia  is  present,  thus  rendering  it  non-cohesive,  and  protecting 
it  from  other  gases.  If  desired,  cohesiveness  may,  of  course,  be  re- 
stored by  anneahng.  For  this  purpose,  gas,  alcohol,  or  electricity 
may  be  used  as  a  means  of  heat.  Gas,  alcohol,  or  any  open  flames 
are  objectionable  on  account  of  contaminations,  grain  alcohol  being 
the  least  so.  A  sheet  of  mica  or  a  porcelain  tray  may  be  used  between 
the  flame  and  the  gold,  thus  reducing  the  objection  to  a  minimum. 
The  electric  annealer  is  by  far  the  best.*  It  distributes  the  heat  evenly 
*The  Custer  electric  annealer  is  generally  recognized  as  the  superior  make. 


236 


FILLING    MATERIALS. 


and  at  varying  degrees.  It  also  does  away  with  handling  the  gold 
during  the  annealing  process. 

In  discussing  the  insertion  of  gold,  it  is  assumed  that  the  cavity 
is  prepared  according  to  the  principles  laid  down  in  chapter  on  the 
preparation  of  cavities  for  fillings. 

Non-cohesive  gold  is  not  used  very  frequently  for  the  entire  cavity, 
since  surrounding  walls  are  necessary  to  its  insertion,  and  in  this  day 
of  specialization  few  men  are  enabled  to  acquire  skill  in  its  application. 
There  seem  to  be  scarcely  enough  points  in  its  favor  to  compensate 
for  the  time  consumed  in  acquiring  this  skill.  Its  use  is  limited  to 
simple  cavities.  As  no  union  of  the  gold  laminae  takes  place,  the  wedge 
principle  of  insertion  must  be  depended  upon. 

The  cylinder  is  the  best  shape  to  use  for  this  work.  It  should  be 
somewhat  longer  than  the  depth  of  the  walls  against  which  it  is  to  be 
forced.  Several  cylinders  are  placed  endwise  in  the  cavity,  and  forced 
against  each  surrounding  wall  with  a  wedge-shaped  instrument,  thus 
leaving  a  space  in  the  center  within  which  are  placed  other  cylinders 


Figs.  187 


I 


195- 


until  it  is  impossible  to  make  room  for  any  more.  The  whole  mass  is 
then  condensed  by  a  suitable  plugger  point,  the  outer  ends  thus  being 
forced  as  far  as  possible  into  the  cavity.  The  cylinders  should  always 
be  of  sufficient  length,  so  that,  when  tightly  wedged  and  finally  con- 
densed, the  cavity  will  be  over  full. 

It  is  claimed  for  the  non-cohesive  filling  that  when  it  is  used  water- 
tight margins  are  more  perfectly  made,  and  fillings  are  inserted  with 
greater  dispatch,  provided  the  peculiar  skill  demanded  for  its  manip- 
ulation has  been  acquired. 

Filling  cavities  with  cohesive  gold,  an  art  which  requires  years 
to  master,  demands  less  theorizing  than  demonstration,  more  actual 
experience  than  ponderous  texts,  so  decidedly  practical  are  all  its 
details.  Success  is  based  upon  many  considerations,  to  some  of  which 
reference  has  already  been  made.  The  importance  of  modern  cavity 
preparation  cannot  be  too  strongly  emphasized,  for  upon  it  much  de- 
pends. Separation  of  the  teeth  for  the  purpose  of  accessibility,  and 
fixation  to  render  the  attachment  tense,  are  also  of  moment. 


GOLD. 


237 


Figs.  198,     199.      200.     201. 


A  large  variety  of  plugger  points  is  needed  to  fill  special  wants, 
but  for  ordinary  purposes  the  dentist  confines  himself  to  a  few  forms 
with  which  he  has  become  thoroughly  familiar.  The  illustrations, 
Figs.  187  to  197,  will  be  referred  to 
as  occasion  demands. 

The  shank  of  each  plugger  should 
bend  a  few  degrees  so  that  it  will  not 
interfere  with  the  operator's  view  of 
the  working  point.  The  modern  law 
of  accessibility  in  cavity  preparation 
has  limited  the  modifications  in  the 
shank  to  only  three  besides  the 
above;  namely,  the  bayonet,  the  right 
angle,  and,  for  special  work,  the 
complete  reverse.  (Figs.  198,  199, 
200,  201,  202.) 

All  should  be  finely  serrated.  It  is  also  well  to  remem- 
ber that  .5  mm.  is  about  as  large  condensing  area  of  a 
point  as  should  ever  be  used.  The  force  necessary  to  con- 
dense gold  with  larger  areas  is  generally  unbearable,  and  is 
also  liable  to  cause  bridging  over  or  imperfections  in  solidity. 
Small  points  which  pierce  the  gold  should  not  be  used. 

Another  factor  to  consider  is  the  manner  of  obtaining 
condensing  force.  Hand  pressure  is  the  simplest.  The 
hand  mallet,  the  automatic  and  other  mechanical  inventions, 
are  all  applied  more  or  less.  Dr.  Black  recommends  the 
mallet  in  the  hands  of  an  assistant  as  the  best  means.  It 
should  be  a  rule  always  to  place  the  gold  where  wanted  in 
the  cavity,  and  closely  pack  its  laminae  with  a  light  hand 
pressure,  then  mallet  until  the  required  solidity  is  obtained. 
The  force  should  be  so  directed  as  to  distribute  itself  evenly 
over  the  tooth-attachment;  that  is,  toward  the  long  axis. 
This  causes  the  least  inconvenience  to  the  patient. 

Perfect  adaptation  to  cavity  walls  and  margins,  and 
adequate  condensation,  are  the  chief  objects  of  attainment 
in  these  fillings.  Both  are  interfered  with  by  over-annealing. 
In  fact,  the  very  first  pieces  introduced  in  the  cavity  may 
be  unannealed  cohesive  gold,  which  secures  more  easily, 
and  with  more  certainty,  the  above-mentioned  adaptation. 
Masses  of  gold,  if  too  large,  cannot  be  properly  placed  and  condensed. 
For  starting  the  filling,  3^0^  of  a  sheet  No.  4  foil  is  quite  sufiicient,  or 


Fig.  202. 


238  FILLING    MATERIALS. 

an  amount  that  may  be  readily  anchored  into  one  angle  of  the  cavity. 
It  is  generally  not  advisable  to  use  a  mass  of  gold  the  bulk  of  which  is 
more  than  one-third  the  size  of  the  cavity.  .         ,,-^. 

A  solid  plug  is  obtained  only  by  carefully  welding  each  newly  added 
mass  to  that  already  in  the  cavity.  In  doing  this,  the  force  exerted 
in  manipulation  must  not  in  any  way  distort  the  filling  or  interfere 


Fig.  203. 


Fig.  204. 


Fig.  205. 


Fig.  206. 


Fig.  207. 


Fig.  203. — Axio-mesio-distal  plane. 
Fig.  204. — Axio-mesio-distal  plane. 
Fig.  205. — Axio-mesio-distal  plane. 


Showing  gold  started. 

Showing  floor  covered  and  advance  of  axial  walls 
Overfull  and  ready  for  finishing. 
Fig.  206. — Longitudinal  section,  Bucco-lingual  plane,  mesial  fourth,  through  retention 
orm  of  cavity.     Showing  gold  started.     Dotted  lines  represent  the  outline  form  of  the 
cavity. 

Fig.  207. — Same  as  Fig.  206.    Showing  the  union  complete,  and  surface  brought  up. 


with  adaptation,  but  rather  be  so  directed  as  further  to  insure  adapta- 
tion and  stability.  The  plugger  should,  therefore,  generally  proceed 
from  the  center  to  the  periphery.  It  is  never  judicious  to  exert  force 
on  thin  layers  of  gold  covering  flat  surfaces.  Moreover,  in  covering 
margins,  especial  care  should  be  taken  to  have  a  good  cushion  of  gold 


Fig  208. 


Fig,  209. 


Ftg.  210. 


Fig.  211. 


Fig.  208. — Longitudinal  section,  Mesio-distal  plane,  Buccal  fourth.  Showing  gold 
started  (as  in  Fig.  206). 

Fig.  209. — Showing  the  progression  of  the  gold  building  after  gingival  wall  has  been 
covered. 

Fig.  210. — Same  section  and  plane,  but  cut  through  middle  of  tooth.  Showing  locking 
of  step,  and  proximal  part  of  filling. 

Fig.  211. — Same  as  preceding.     Gold  building  complete. 

over  the  margins,  thus  avoiding  danger  of  the  plugger  point  coming  in 
contact  with  the  tooth  tissue. 

In  filling  a  simple  cavity,  the  process  of  building  the  gold  is  illus- 
trated in  Figs.  203,  204,  205.  Plugger  points  187,  188,  191  and  196, 
are  used  in  this  class  of  cavities  in  the  anterior  teeth,  and  as  we  go 
back  into  the  mouth  the  bayonet,  194,  wiU  also  be  needed. 


GOLD.  239 

The  filling  of  a  complex  cavity  is  best  illustrated  in  the  mesio- 
occlusal  of  a  first  upper  molar.  (Figs.  206  to  211.)  The  axio-bucco- 
and  axio-linguo-gingival  point  angles  are  first  filled,  and  then  the  axio- 
gingival  line  angle  is  covered,  starting  from  each  point  angle  re- 
spectively, so  that  the  surface  represents  an  angle  of  45  degrees 
with  the  axial  or  gingival  wall,  and  the  latter  is  built  out  upon  until 
its  margin  is  fully  covered.  The  filling  should  then  proceed  swiftly  to 
the  contact  point,  and,  in  doing  so,  one  should  as  nearly  as  possible  pre- 
serve a  flat  surface;  but  the  inclination  from  buccal  to  lingual  may 
vary  according  to  accessibility.  For  this  part  of  the  work  pluggers 
187,  188,  192  and  193  are  used  for  starting  the  fiUing,  and  194,  195, 
196  and  197  for  further  condensing.  The  step  portion  of  the  cavity  is 
started  in  the  same  manner  as  the  simple  cavity,  but  instead  of  building 
up  over  the  missing  wall,  the  operator  laps  the  gold  over  the  proximal 
portion,  and  builds  the  whole  out  until  it  is  overfull. 

The  practice  of  making  mesio-occlusal-distal  fillings  in  one  opera- 

bbDb 

Fig.  212.  Fig.  213.  Fig  214.  Fig  215.  fic.  216. 

Fig   212. — Mesio-distal  plane.     Showing  the  starting  of  gold. 

Fig.  213. — Same  as  Fig.  212.  Showing  progress  of  gold  building  and  union  of  incisal 
part  with  the  rest  of  the  filling. 

Fig.  214. — Same  section.     Gold  building  finished. 

Fig.  215. — Axio-mesio-distal  plane  Showing  process  of  gold  building  in  carities 
nvolving  angle 

Fig.  216. — Same  section  as  215.     Gold  building  finished. 

tion  should  be  discouraged.  It  is  economy  in  every  respect  to  make 
two  proximo-occlusal  fiUings  instead;  however,  they  may  be  so  inter- 
locked as  to  represent  the  same  outline  form  as  the  mesio-occluso- 
distal  filling. 

The  proximal  cavities  of  the  anterior  teeth  present  some  difficulties 
owing  to  the  fact  that  we  have  less  surrounding  wall.  (Figs.  212  to  214.) 
For  illustrative  purposes  take  the  mesial  of  a  central  incisor.  The 
gingival  point  angles  are  filled  first,  and  the  axio-gingival  line  angle  is 
covered  as  described  in  the  preceding  case.  The  surface  of  gold 
should  then  be  built  toward  the  incisal,  preserving  an  angle  of  about 
45  degrees,  and  it  should  be  borne  in  mind  constantly  that  the  lingual 
portion  is  to  be  kept  in  advance.     The  incisal  retention  form  is  filled 


240  FILLING    MATERIALS. 

as  soon  as  the  gold  can  be  attached  from  it  to  the  main  portion,  and  the 
body  of  gold  thus  tied  and  strengthened. 

Great  care  should  be  taken  in  covering  the  margin  both  lingually 
and  labially  at  the  proper  time,  and  also  in  sufficiently  contouring  the 
lingual.  In  cavities  involving  the  angle  v^ithout  a  step,  the  building 
of  the  gold  is  continued  to  proper  contour.  (See  Figs.  215  and  216.) 
Pluggers  used  for  the  gingival  retention  form  are  187,  188,  and  189; 
for  the  body  of  the  filling,  195,  196,  and  197;  for  the  incisal  retention 
at  times  necessary  to  add,  190. 

When  the  incisjal  edge  is  involved,  and  the  step  preparation  has 
been  made,  the  filling  of  the  proximal  portion  is  proceeded  with  pre- 
cisely as  described  until  the  step  is  reached.     The  retention  form  in  the 


Fig.  217.  Fig.  218.  Fig.  219.  Fig.  220.  Fig.  221. 

Fig.  217. — Mesio-distal  plane.     Showing  disto-pulpal  angle  filled. 

Fig.  218. — Same  as  preceding,  further  progress. 

Fig.  219. — Same  as  Fig.  218.     Gold  building  completed. 

Fig.  220. — Upper  second  bicuspid.  Axio-bucca-lingual  plane.  Showing  the  three  non 
cohesive  cylinders  of  gold  in  place. 

Fig.  221  — The  same  tooth  as  that  in  Fig.  220.  Axio-mesio-distal  plane,  showing 
partially  condensed  mass  of  non-cohesive  gold  projecting  over  gingival  cavo-surface  angle, 

incisal  part  is  then  filled  from  the  disto-pulpal  angle,  and  the  gold 
built  dov^^n  so  that  its  surface  v^^ill  present  an  angle  of  45  degrees  with 
the  pulpal  wall,  and  on  towards  the  proximal  portion,  covering  the  in- 
cisal edge.  Lastly,  the  union  of  the  two  portions  is  completed,  and 
carried  out  to  contour.  The  force  exerted  here  should  always  be  so 
as  to  drive  the  whole  filling  more  tightly  into  its  retention  and  resistance 
forms.     (Figs.  217  to  219.) 

In  the  filling  of  a  mesio-inciso-distal  cavity  in  the  six  anterior  teeth, 
the  proximal  portions  are  filled  as  before;  in  filling  the  incisal  portion, 
however,  the  center  should  proceed  faster  than  the  angles,  and  it  is 
also  best  to  build  one  angle  out  to  contour  first,  remove  the  separator, 
and  proceed  with  the  remaining  one  exactly  as  before. 

A  great  deal  has  been  said  about  the  percentage  of  failures  of 
adaptation  to  the  gingival  wall  in  bicuspids  and  molars  when  using 
cohesive  gold  for  the  entire  cavity,  although  on  this  point  statistical 
figures  may  vary  quite  as  widely  as  do  opinions  of  what  legitimately 


GOLD. 


241 


may  constitute  such  figures.  Some  of  the  best  operators  prefer  to 
use  a  certain  amount  of  non-cohesive  gold  in  the  gingival  part  of  the 
cavity.  The  advantage  is,  besides  better  adaptation,  a  saving  of  time 
which  is,  of  course,  a  vastly  important  factor  in  the  economics  of  the 
question. 

The  non-cohesive  gold  should  not  fill  the  whole  of  the  retention 


Fig.  222. — Labial  view  of  six  anterior  teeth.     Showing  contour  and  contact. 

form.  The  usual  method  of  procedure  is  to  place  one  cylinder  in  the 
axio-linguo-gingival  point  angle,  another  in  the  axio-bucco-gingival, 
with  a  third  between,  and  partially  force  them  together  with  the  plug- 
gers  192  and  193.  The  cylinders  used  should  be  about  twice  as  long 
as  the  gingival  wall  is  wide  mesio-distally  to  allow  for  after-conden- 
sation. (See  Figs.  220  and  221.)  The  cohesive  gold  is  now  forced 
into  the  non-cohesive,  using  an  assistant  plugger,  while  locking  the 
gold  from  the  lingual  to  the  buccal  wall.     Thus  the  cohesive  gold 


Fig.  223. 


Fig.  224. 


Fig.  223. — Buccal  view  of  bicuspids  and  molars.     Showing  contour  and  contact. 

Fig.  224. — Occlusal  view  of  upper  bicuspid  and  molar.     Showing  contour  and  contact. 


really  forms  the  fourth  surrounding  wall  for  the  non-cohesive.  Thence 
the  filling  is  proceeded  with  as  in  the  operation  already  described 
where  cohesive  gold  was  used  for  the  entire  cavity. 

The  final  condensation  of  the  non-cohesive  gold  takes  place  from 
the  surface,  by  means  of  large  parallelogram  pluggers  (see  Figs.  197, 
198,  199,  and  200,  the  last  three  for  distal  surfaces). 

In  finishing,  it  is  assumed  that  the  cavity  has  been  overfilled  to 
allow  for  trimming  away  of  enough  gold  to  leave  a  perfectly  smooth 
surface,  and  still  have  proper  contour.  The  instruments  and  appli- 
16 


242 


FILLING    MATERIALS. 


Fig.  225. — Occlusal  view  of 
lower  bicuspid  and  molar.  Show- 
ing contour  and  contact. 


ances  for  this  purpose  are  many.  Of  them,  the  following  are  indispen- 
sable: A  plentiful  supply  of  corundum  stones  in  various  sizes  and 
grits,  sandpaper  discs  and  strips,  the  Wilson  saw  frame  (Fig.  226) 
and  saws  cut  down  to  a  thread-like  thinness,  Dr.  G.  V.  Black's  trim- 
ming knives  (Figs.  227,  228,  229)  and  Dr. 
E.  K.  Wedelstaedt's  gold  files.  (See  illus- 
tration. Fig.  230.) 

Generally  the  first  cutting  is  done  with 
the  aid  of  corundum  stones  or  sandpaper 
discs  and  strips,  depending  upon  locality, 
and,  in  proximal  positions,  the  saw  is  an 
adjunct  of  great  importance.  Thereafter,  the  steel  instruments,  chisels 
and  excavator  for  inaccessible  places  in  occlusal  fillings,  trimming 
knives  and  files,  and,  for  the  final  smoothing,  cuttle-fish  discs,  pumice 
stone,  whiting,  or  rouge,  used  with  suitable  appliances. 

The  chief  watchword  in  this  part  of  the  work  should  be:  Lacerate 
the  tissues  as  little  as  possible;  reproduce  natural  form  plus  the  needed 

contour  and  contact  point  (Figs.   222  to  225);   obtain  as       ^ 

smooth  a  surface  as  possible  so  that  an  explorer  will  pass 
from  filling  to  tooth  tissue  without  catching.  Always  cut 
from  the  gold  to  the  tooth  tissue  as  far  as  possible.  As  to 
the  use  of  the  knives,  only  thin  shavings  should  be  cut,  and 
the  force  should  be  directed  so  as  not  to  disturb  the  filling. 

Occlusal  fillings  are  first  ground  down  with  corundum 
stones  and  water,  starting  with  reasonably  coarse  grits,  and 
finishing  with  finer  ones.  A  variety  of  shapes  is  necessary 
in  order  to  reach  well  into  grooves  and  variations  in  sur- 
faces. A  good  polish  can  be  obtained  by  using  fine,  wet 
pumice  stone  powder  applied  with  wooden  wheels  or  points, 
rubber  discs,  or  moosehide  wheels.  This  may  be  followed 
with  whiting  and  even  rouge  for  a  very  high  degree  of  polish. 

In  buccal,  labial,  and  lingual  fillings,  the  use  of  discs 
should  be  substituted  for  part  of  the  corundum  work;  but 
both  these  materials  are  very  liable  to  cut  too  much  into 
the  filling.  The  pointed  fissure  burs  can  be  used  over  the  p^^  ^^^ 
gingival  margin.  The  Black  trimming  knives  and  Wedel- 
staedt  files  are  all  of  use  here.  The  polishing  is  done  as  above 
indicated. 

In  the  proximo-occlusal  fillings  the  saw  is  passed  under  the  gin- 
gival overhang,  and  should  be  first  drawn  carefully  toward  the  contact 
point,  and  with  it  as  much  as  possible  of  the  remaining  overhang 


GOLD. 


243 


Figs. 
22S    227 


229 


should  be  removed,  or  as  much  as  the  limitation  of  movement  will 
allow.  The  trimming  knives  can  now  be  used,  and  should  be  followed 
by  the  files,  with  some  care  to  guard  against  too  much 
cutting;  the  needed  contour  and  symmetry  of  shape  must 
always  be  remembered. 

Further  smoothing  is  done  with  sandpaper  discs  and 
strips,  followed  by  the  usual  polishing  process.  It  is 
often  necessary  to  carry  the  polishing  powders  on  linen 
tape  over  the  proximal  portion,  in  order  to  finish  thor- 
oughly. 

In  proximal  fillings  in  the  six  anterior  teeth,  the  first 
cutting  is  usually  done  with  sandpaper  discs  and  strips, 
although  the  corundum  stones  are  material  aids  on  both  labial 
and  lingual  surfaces,  especially  the  latter.  It  may  also  be  neces- 
sary to  use  the  saw,  knives  and  files  for  the  purpose  of  removing 
the  gingival  overhang;  but  they  are  perhaps  not  needed  so  much 
here  as  in  the  posterior  teeth.  Polishing  is  done  with  cuttle-fish 
discs  and  strips,  and  with  the  powders.  The  incisal  angle  and 
edge,  when  involved  in  a  filling,  demand  a  greater  use  of  corun- 
dum stones  and  sandpaper  discs. 

Considered  as  a  stopping,  nothing  as  yet  has  quite  taken  the 
place  of  gold,  although  it  cannot  be  said  to  apply  perfectly  to  all 

cases.  A  full  knowledge  of  its  properties, 
behavior,  and  working  qualities,  is  the  first 
essential.  With  skillful  instrumentation 
and  bulldog  persistence,  one  ought  to  be 
able  to  conquer  the  art  of  making  nearly 
perfect  gold  fillings  in  a  comparatively  short 
time,  say  in  from  five  to  ten  years. 

Reference  has  been  made  to  the  dis- 
covery of  the  cohesive  property  of  gold  as 
marking  an  epoch  in  the  history  of  tooth- 
Another  epoch  may  be  said  to  have  been  ushered  in  by 
the  scientific  and  artistic  work  of  Dr.  G.  V.  Black.  The  world- 
wide influence  exerted  by  this  great  worker  may  be  noted  in 
papers,  reports  of  clinics,  etc.,  published  in  the  various  journals 
by  members  of  the  G.  V.  Black  Club  (Inc.)  of  St.  Paul.  This 
organization  has  done  much  to  simplify  gold  fiUing,  and,  in 
general,  not  only  through  its  home  meetings,  but  in  state, 
national,  and  international  gatherings,  has  done  much  to  further  the 
progress  of  operative  dentistry. 


i 


i 


Fig.  230.— Dr.   E.   K. 
Wedelstaedt's  gold  files. 


filling. 


244  FILLING    MATERIALS. 


AMALGAM. 


Owing  to  the  plasticity  conferred  upon  an  alloy  of  one  or  more 
metals  with  mercury,  amalgam  is  usually  spoken  of  among  the  plastic 
filling  materials.  What  takes  place  in  the  union  is  the  lowering  of 
the  fusing  point  of  the  alloyed  metals  by  introducing  mercury,  a  plastic 
stage  thus  ensuing  before  crystallization  is  complete.  This  plasticity 
and  subsequent  crystallization — both  interesting  phenomena — led  to  its 
introduction  as  a  filling  material. 

The  study  of  amalgam  is  somewhat  complex  because  we  have  to 
deal  with  an  alloy  of  certain  metals  not  always  constant  in  physical 
properties  out  of  the  mouth,  and  hable  to  still  greater  modification 
after  introduced  into  the  cavity  as  an  amalgam.  For  various  appli- 
cations in  the  arts,  metals  are  alloyed  to  gain  specific  ends  not  obtain- 
able by  any  one  of  them  alone:  to  increase  hardness,  strength,  tough- 
ness, elasticity,  and  resistance  to  corrosion;  to  lower  the  fusing  point; 
to  modify  color,  etc. 

Alloy  making  and  application  were  known  to  the  ancients,  although 
they  did  not  always  produce  what  they  intended  to,  nor  did  they  know 
very  much  about  the  separate  elements.  Alloy  for  amalgam  fillings 
was  introduced  in  the  first  quarter  of  the  last  century.  Things  were 
done  on  a  more  or  less  empirical  basis  until  the  impetus  of  scientific 
method  altered  matters.  Although  formulas  may  not  have  changed 
markedly,  there  has  been  undoubted  improvement  as  to  certainty  of 
procedures  and  results.  It  was  the  general  lack  of  applied  science 
which  made  it  so  difficult  for  amalgam  to  take  its  present  place  of  use- 
fulness, and  we  owe  a  debt  of  gratitude  to  all  the  zealous  workers  who 
have  combined  to  give  it  that  place.  The  early  prejudice  against  it 
was  due  to  its  non-scientific  composition  and  use.  It  is,  perhaps, 
needless  to  say  that  amalgam  has  been  criminally  abused  in  the  past, 
and  that  the  better  conditions  which  might  naturally  be  expected  from 
scientific  workers  have  not  been  commensurate  with  their  efforts. 
Its  plasticity  readily  betrays  operators  into  unwarranted  speed — a  fact 
which  is  only  too  soon  recognized  by  the  charlatan  class. 

Some  properties  of  amalgam  should  be  noted.  Its  color  is  grayish 
white.  It  is  generally  spoken  of  as  brittle,  although  under  certain 
conditions  it  manifests  a  degree  of  malleability  known  as  "flow." 
It  is  harder  than  silver,  but  not  very  tenacious.  Gases  are  condensed 
upon  its  surface  to  a  larger  degree  than  with  gold.  As  to  conductivity, 
all  alloys  have  less  of  this  property  than  do  the  simple  metals.  These 
properties  are  modified,  first,  according  to  the  number  and  quantity 


AMALGAM.  245 

of  the  various  metals  added;  and,  second,  according  to  the  mode  of 
making. 

As  to  the  manner  in  which  amalgam  fulfills  the  requirements  of  a 
filling  material:  It  may  be  said  to  be  practically  indestructible  in 
the  mouth.  Chemical  action  of  any  kind  is  always  more  energetic  in 
alloys,  hence  amalgam  unites  easily  with  oxygen  and  sulphur.  In 
adaptation  to  cavity  walls,  it  is  nearly  as  good  as  gold.  The  change  in 
form  in  amalgam,  due  to  contraction  and  expansion,  so  noted  in  the 
past,  has  been  reduced  by  modern  science  to  the  minimum.  It  with- 
stands attrition  well,  and,  in  general,  the  forces  of  mastication  are  not 
so  manifest  upon  well-made  fillings  of  this  material  as  upon  those  of 
gold.  Its  color  is  one  serious  drawback.  Its  conductivity  is  low,  far 
lower  than  that  of  gold.  As  to  ease  of  manipulation,  this  property 
increases  in  proportion  to  the  amount  of  mercury  introduced  in  the 
alloy;  but  the  operator  must  choose  between  this  advantage  and  the 
superior  one  of  firmness,  for,  if  the  latter  be  the  desideratum,  it  must 
be  had  at  the  expense  of  the  former.  In  susceptibility  to  polish,  it 
fulfills  the  demand. 

The  properties  of  amalgam  decide  its  application,  to  a  large  extent; 
for  instance:  its  color  limits  its  use  to  the  posterior  teeth,  or  where  it  is 
little  noticed;  the  possibility  of  easy  manipulation  often  determines 
its  use  in  cavities  inaccessible  to  gold.  So  then,  generally  speaking, 
it  can  be  used  in  the  bicuspids  and  molars,  especially  in  cases  where 
more  nearly  perfect  results  can  be  obtained  than  by  the  use  of  gold. 
However,  if  exposed  to  view  to  any  extent,  it  is  contra-indicated.  We 
may  say  that  so  far  as  it  is  peculiarly  adapted  to  such  selected  cases, 
it  becomes  the  ideal  material. 

If  success  is  to  be  obtained  in  amalgam  work,  the  following  points 
must  be  carefully  considered:  The  individual  metals  used;  the  purity 
and  the  proportion  of  the  metals;  the  manner  of  production;  and  the 
manipulative  procedure.  The  study  of  the  chemical  and  physical 
constants  of  the  metals  is  imperative.  As  to  the  behavior  of  metals 
toward  one  another  in  alloys,  it  may  be  said  that  mixtures  are  not 
merely  mechanical.  They  are  in  the  nature  either  of  a  solution  of  one 
metal  in  another,  or  of  a  chemical  combination.  A  chemical  combina- 
tion may  be  a  pure  one,  or  it  may  provide  an  excess  of  one  of  the  metals 
in  which  latter  case  the  excess  is  mingled  mechanically  with  the  mechani- 
cally combined  constituents.  Proportion,  temperature,  etc.,  of  course 
determine  the  final  manner  or  manners  of  the  combination. 

There  is  no  hard  and  fast  rule  regarding  the  reciprocal  action  of 
metals  in  alloys.     Some  metals  alloy  easily  in  any  proportions;  some 


246  FILLING    MATERIALS. 

less  easily  and  in  only  set  proportions;  and  again  others  alloy  with 
extreme  difficulty  under  any  conditions.  As  a  rule,  metals  of  similar 
chemical  nature  have  greater  affinity  as  alloys  than  those  which  differ. 

Mention  should  be  made  of  the  fact  that  only  chemically  pure 
metals  'ought  to  be  employed.  Otherwise,  unaccountable  variation 
will  manifest  itself. 

The  proportion  of  metals  is  of  considerable  moment.  Experiments 
have  shown  that  like  quantities  of  metals  alloyed  alike  produce  cer- 
tain results.  Furthermore,  the  addition  of  a  very  minute  quantity  of 
some  metals  is  capable  of  causing  great  modification  in  the  properties 
of  the  resultant  alloy.  The  manner  of  production  is  of  tremendous 
importance,  for  instance: 

If  metals  be  heated  to  a  temperature  beyond  the  fusing-point,  a 
different  atomic  grouping  may  occasionally  result.  The  length  of 
time  they  are  kept  in  the  fluid  state,  the  mixing  process,  the  various 
methods  of  cooling  and  casting,  may  noticeably  modify  an  alloy.  In 
some  cases  when  cooled  slowly,  they  will  separate  into  several  alloys  of 
differing  compositions;  that  is,  the  alloys  with  a  higher  fusing-point 
solidify  first.  This  is  spoken  of  as  liquation.  At  the  same  time  spe- 
cific gravity  may  manifest  itself  so  that  the  lightest  alloys,  if  solidified 
last,  may  be  uppermost.  If  liquation  take  place,  there  will  be  not  only 
variation  in  composition,  but  also,  to  a  marked  degree,  in  the  properties. 
Liquation  should,  therefore,  be  prevented  as  far  as  possible  wherever 
constancy  of  properties  ought  to  prevail.  This  can  in  the  main  be 
accomplished  by  rapid  cooling. 

It  is  clear  then,  that  much  depends  upon  the  manner  of  production. 
The  foregoing  remarks  may  be  made  more  clear  by  a  description  of  the 
process  of  making  dental  amalgam  alloy: 

Take  the  formula  60  per  cent  silver,  35  per  cent  tin,  4  per  cent  cop- 
per, I  per  cent  zinc.  To  make  10  oz.  we  shall  need  6  oz.  silver,  3^  oz. 
tin,  8  dwts.  copper,  2  dwts.  zinc.  Zinc  is  added  in  the  combination  of 
brass,  because  free  it  is  easily  volatilized  and  oxidized.  The  brass, 
however,  should  be  of  known  proportions,  say  75  per  cent  copper 
and  25  per  cent  zinc  (a  constant  alloy).  The  weight  will  then  be  2 
dwts.  copper  and  8  dwts.  brass.  The  brass,  copper,  and  silver  are 
fused  in  a  plumbago  crucible  first.  The  tin  is  fused  in  a  separate 
ladle,  and  added  as  soon  as  the  first  three  are  in  fluid  condition.  Fusing 
all  the  metals  at  once  has  been  tried,  and  analysis  and  experiment  show 
greater  variation.  Some  stirring  is  necessary  until  the  pouring  out 
begins.  A  quarter  inch  steel  mold  about  four  inches  wide  cools  the 
alloys  fast  enough.     One  out  of  every  thousand  melts,  as  above,  were 


AMALGAM.  247 

subjected  to  analysis  by  Prof.  C.  J.  Bell  in  the  chemical  laboratory  of 
the  University  of  Minnesota.  Five  sections  of  the  bar  were  made, 
and  the  percentage  of  each  metal  was  very  nearly  the  same  in  all,  and 
according  to  formula. 

If  thicker  castings  be  made,  liquation  is  very  liable  to  take  place. 
The  bar  can  be  reduced  by  means  of  a  twelve-inch  bastard  file,  and 
strained  through  a  brass  wire  mesh.  Iron  filings  from  file  and  bench 
vise  may  be  removed  by  passing  the  magnet  through  for  several  min- 
utes, and  it  is  then  aged  by  subjecting  it  to  the  temperature  of  boiling 
water  for  about  twenty  minutes;  the  mass  is  placed  in  a  beaker,  and 
introduced  into  a  pot  of  boiling  water. 

The  silver  is  added  for  its  hardening  and  settling  qualities;  it  also 
causes  expansion.  Tin  is  added  chiefly  to  counteract  the  expansion 
caused  by  the  silver,  and  to  retard  the  setting.  Copper  increases 
hardness  and  strength,  and  has  some  effect  upon  color.  Zinc  heightens 
the  color,  and  somewhat  hastens  the  setting. 

The  percentages  of  dental  amalgam  alloys  have  been  determined 
by  experiment.     For  a  detailed  study  of  them  the  reader  is  referred  to 


Fig.  231. 

the  scientific  investigations  of  Dr.  G.  V.  Black  {Dental  Cosmos,  Vol. 
28,  and  elsewhere). 

Dental  amalgam  alloys  are  classified  as  binary,  ternary,  etc.,  accord- 
ing to  the  number  of  metals  added. 

With  amalgam  the  most  vital  point  for  consideration  is  the  manipu- 
lative procedure.  Not  only  is  the  percentage  of  mercury  to  be  reck- 
oned with,  but  also  its  incorporation,  the  compression  of  the  mass, 
trimming  and  finish,  are  all  elements  that  figure  prominently  in  the 
results.  One  reason  that  this  material  has  not  reached  a  higher  plane 
generally  is  a  lack  of  sufficient  study  and  attention  to  minutiae  and 
detail  in  the  technique  of  insertion.  This  deficiency  should  be  more 
widely  acknowledged  and  repaired. 

It  has  been  the  writer's  privilege  to  observe  several  hundred  amal- 
gam operations  made  by  Dr.  F.  H.  Orton,  of  St.  Paul,  during  the  past 
twelve  years.  The  results  have  been  uniform,  and  as  nearly  perfect 
as  are  ever  seen.  His  method  of  procedure  is  incorporated  in  the  fol- 
lowing description  of  filling  a  cavity  with  amalgam: 

The  cavity  is  prepared  as  for  gold,  with  this  difference,  that  the 


248 


FILLING    MATERIALS. 


Fig.     232. — Black's    hand 
pressure  amalgam  instruments 


enamel  bevel  should  be  somewhat  longer.  All  cavities  must  be  simple; 
if  not  so  in  the  first  place,  they  must  be  made  so  by  adjusting  a  matrix 
to  replace  the  missing  wall.  The  matrix  should  be  unyielding  and  fit 
closely  to  the  tooth-surface.     The  amalgam  is  prepared  by  placing 

the  mercury  in  the  palm  of  the  hand,  and 
gradually  adding  the  alloy  until  affinities 
are  practically  satisfied.  The  hand  should 
be  perfectly  clean  and  dry.  The  incorpora- 
tion of  the  ingredients  is  accomplished  by 
rubbing  with  a  glass  pestle.  (See  Fig.  231.) 
Both  judgment  and  skill  are  necessary  to 
obtain  the  proper  mix;  a  certain  crepitus  is 
noticed  when  the  mass  is  about  ready,  and 
some  experience  will  enable  one  to  know 
when  this  point  is  reached.  It  should  be  an  object  to  have  as 
little  surplus  mercury  as  possible  when  the  mixing  is  finished;  there- 
fore it  is  forced  out  in  chamois  skin  or  muslin  with  heavy  pliers  so 
much  so  that  the  mass  should  resemble  a  hard,  flat  cake  which  fractures 
sharply.  In  packing  the  amalgam  the  object  is  density  and  complete 
union  of  all  the  particles.  As  it  is  some- 
what plastic,  the  plugging  points  should 
be  as  large  as  the  cavity  will  permit,  and 
with  serrated  surfaces  (see  Figs.  232,  233, 
and  234).  Hand  pressure  as  ordinarily 
understood  is  not  sufiicient;  hence  the  aid 
of  the  mallet  comes  in,  using  bayonet 
shanks  as  illustrated.  It  will  be  found 
that  it  requires  a  rather  heavy  blow  from 
the  mallet  to  compress  the  amalgam,  and 
that  the  blows  must  be  repeated  until  the 
mercury  appears  under  the  plugger  point. 

is  then  removed  by  the  aid  of  gold  foil,  the  two  metals  having  a 
marked  afl&nity  for  each  other.     A  cylinder  of  gold  foil  is  placed 
upon  the  surface,  covered  with  spunk,  pressed  down  and  removed. 
More  amalgam  is  then  added,  and  the  process  is  repeated  until 
the  cavity  is  overfull.     Importance  should  be  attached  to  the 
removal  of  the  surplus  mercury  whenever  it  appears;  if  allowed  to 
remain,  it  weakens  the  mass.     If  care  is  taken,  the  amalgam  will  be 
sufficiently  crystallized  to  admit  of  trimming  immediately.     For  occlu- 
sal surfaces  large  spoon  excavators  should  be  used,  and  for  proximal, 
trimming  knives  and  coarse  cuttle-fish  strips  and  discs.     Fillings  in 


li 


I 


Fig.  233.  —  Black's 
amalgam  instruments 
with  bayonet  shanks  for 
mallet  use. 

This  surplus  mercury 


TIN. 


249 


Other  positions  present  few  difficulties  in  trimming.  The  same  instru- 
ments with  some  additional  chisels  or  excavators  for  special  inequali- 
ties will  be  found  all-sufficient. 

It  is  best  to  postpone  for  a  day  the  final  polishing.  First  corundum 
stones,  and  then  powders,  are  used,  as  in  the  polishing  of  gold  fillings. 
Since  in  time  these  fillings  undergo  a  slight  change  in  form, 
it  may  be  necessary  to  refinish  afterwards,  as  occasion 
demands. 

The  time  required  to  make  a  good  amalgam  filling  is 
nearly  that  required  for  gold;  therefore  were  it  not  for  the 
fact  that  in  certain  cases  it  excels  all  other  materials, 
there  would  be  no  economy  in  its  use.  Many  large  M  /J 
cavities  may  be  filled  with  amalgam  v/hen  the  malleted 
gold  filling  would  be  entirely  out  of  the  question.  Restor- 
ations of  considerable  magnitude  are  often  made,  whereby 
teeth  are  rendered  useful  for  a  number  of  years. 

Although  amalgam  is  not  proclaimed  as  the  acme  of 
desirability,  it  occupies  a  very  high  place  as  a  tooth 
saver,  and  it  is  well  worth  effort  and  energy  to  increase 
our  knowledge  concerning  it.  There  is  yet  a  wide  field 
open  to  the  investigator  in  alloy  making  and  application. 
With  what  has  already  been  achieved,  however,  the 
student  can  and  should  thoroughly  acquaint  himself,  and 
thus  conserve  time  by  eliminating  the  errors  and  profiting 
by  the  valuable  discoveries  of  the  past. 


TIN. 


Fig.  234.— 
Owre's  right 
and  left  amal- 
gam instru- 
ments for 
use  against 
matrices  at 
junction  o  f 
same  with 
c  a  V  o-surface 
angle. 


For  various  reasons  tin  is  still  used  by  some  dentists, 
and  the  ability  to  insert  a  tin  filling  is  a  test  in  some 
official  examinations.     Hence  this  material  should  be  studied. 

In  color  it  is  white  with  a  tinge  of  yellowish-blue.  When  pure  it 
has  a  bright,  metallic  luster,  and  although  in  normal  air  it  does  not 
easily  tarnish,  it  readily  occludes  gases.  It  is  fifth  in  the  order  of  mal- 
leability, foil  Y¥o¥  of  an  inch  thin  being  obtainable  by  beating.  It 
is  classified  with  the  soft  metals,  and  is  also  of  a  low  grade  of  tenacity, 
being  tenth  in  the  scale  at  2.1  tons  per  square  inch.  Its  specific  gravity 
is  7.3.  It  is  weldable  in  the  cold  state  if  perfectly  pure,  and  purity 
generally  implies  fresh-cut  surfaces.  When  weldability  has  been  in- 
terfered with  by  exposure  to  air,  it  cannot  be  restored  by  annealing. 
As  to  conductivity,  tin  ranks  low:     for  heat,  154;  for  electricity,  114. 

Tin  has  been  used  as  a  filling  material  for  a  century  or  more;  but 


250  FILLING    MATERIALS. 

it  only  partially  fills  the  requirements  of  this  purpose.  It  oxidizes 
readily  in  the  mouth,  is  easily  adapted  to  cavity  walls,  and  undergoes 
no  change  in  form  unless  subjected  to  wear,  and,  when  so,  the  mallea- 
bility and  softness  markedly  manifest  themselves.  Its  color  is  objec- 
tionable. So  far  as  conductivity  is  concerned,  it  is  low  enough  to  be  of 
value.  The  manipulation  is  very  like  much  that  of  gold.  It  receives 
a  fairly  good  pohsh.  Occasional  reference  has  been  made  to  its 
therapeutic  value,  when  used  as  a  filling,  as  a  preventative  of  caries, 
etc.  This  seems  highly  improbable,  excepting  insofar  as  it  replaces 
the  carious  area,  as  does  any  other  filling  material. 

Tin  has  been  recommended  for  cavities  which  are  not  exposed  to 
wear  and  tear,  and  is  practically  limited  to  simple  smooth-surface  cav- 
ities not  exposed  to  view  or  wear.  It  may  have  some  application  to 
cases  of  young  children,  owing  to  its  rather  easy  manipulation. 

It  is  prepared  for  the  dentist  in  several  forms,  but  the  foil  is  chiefly 
used,  between  Nos.  3  and  10.  But,  as  this  soon  loses  the  property  of 
cohesiveness,  the  dentist  had  better  prepare  the  shavings  of  tin  himself, 
when  wanted,  by  casting  an  ingot  upon  a  polishing  mandrel,  attaching 
to  lathe,  and,  with  a  sharp  tool,  cutting  as  fine  shavings  as  desired 
for  the  case  in  hand. 

Its  insertion  is  exactly  according  to  the  method  pursued  with  gold, 
the  only  difference  being  that  the  plugger  points  may  be  more  deeply 
serrated.     The  finishing,  also,  is  the  same  as  in  the  case  of  gold. 

Since  science  has  aided  us  in  establishing  the  status  of  things,  it 
would  seem  as  if  the  future  of  the  tin  filling  were  somewhat  dubious. 
Personal  opinion  need  not  obtrude  itself  here,  for  speculation  belongs 
only  to  the  field  of  theory.  ' 

CEMENT. 

Among  the  applied  arts,  cement,  in  its  various  forms,  has  been 
in  use  for  centuries.  Its  introduction  to  dentistry  did  not  occur  until 
about  fifty  years  ago.  Largely  owing  to  lack  of  science,  it  has  had  a 
degree  of  difficulty  in  establishing  itself  as  a  filling  material,  as  also  had 
amalgam.  For  that  matter,  its  status  quo,  all  told,  is  sti],l  somewhat 
doubtful.  Nevertheless,  it  serves  many  important  and  useful  pur- 
poses— so  much  so  that  we  have  come  to  regard  it  as  indispensable. 

Of  the  three  kinds  of  cement  to  be  considered,  i.  e.,  the  oxychloride 
of  zinc,  the  oxyphosphate  of  zinc,  and  the  oxyphosphate  of  copper, 
the  first  is  at  present  little  used.  The  use  of  zinc  oxychloride  as  "a 
stopping  of  hollow  teeth"  was  first  suggested  because  of  its  plasticity 
when  freshly  mixed,  its  subsequent  hardening,  and  its  apparent  in- 


CEMENT.  251 

dissolubility.  Its  shortcomings  were  soon  discovered,  and  various 
modifications  of  the  powder  and  liquid  were  tried  for  the  purpose  of 
enhancing  its  qualities,  but  to  no  avail. 

The  oxyphosphate  of  zinc,  introduced  some  years  later  than  the 
oxychloride,  gave  promise  of  greater  things.  It  has  largely  taken 
the  place  of  the  oxychloride,  except  for  some  special  purposes  to  be 
noted.  Upon  it  our  main  reliance  was  placed  until  quite  recently 
— in  1891 — when  Dr.  W.  V-B.  Ames,  of  Chicago,  brought  out  the 
oxyphosphate  of  copper. 

Some  general  properties  of  all  cements  should  be  noted:  Plas- 
ticity, facility  of  setting,  granular  structure,  low  strength,  porosity, 
marked  solubility,  and  low  conductivity.  As  to  color,  the  oxychloride 
is  nearest  white,  the  zinc  oxyphosphate  has  various  hues,  while  the 
copper  oxyphosphate  is  the  blackest  of  black.  The  properties  vary 
a  great  deal,  according  to  composition  and  modes  of  mixing,  especially 
those  of  density,  setting,  porosity,  permeabihty,  disintegration,  etc. 

To  a  certain  extent  all  cements  possess  the  essential  qualifications 
for  a  filling.  But  they  are  not  indestructible  in  the  fluids  of  the  mouth, 
especially  under  the  free  margins  of  the  gum.  The  oxychloride  is 
the  worse  in  this  respect.  Their  adhesiveness  to  cavity  walls  is  of 
great  value.  Some  cements  undergo  change  in  form,  particularly 
through  contraction.  None  resist  attrition  well,  although  oxyphosphate 
of  zinc  and  copper  wear  much  better  than  the  zinc  oxychloride.  As 
to  colors,  highly  artistic  results  may  be  obtained  with  some  of  them, 
but  the  black  of  copper  oxyphosphate  limits  the  application  of  it  to 
unexposed  places.  Cements  are  practically  non-conductors  of  heat, 
and  are  often  indicated  for  this  reason.  As  to  ease  of  manipulation, 
they  are  undoubtedly  first  of  all  materials.  They  are  incapable  of 
receiving  or  maintaining  a  very  high  polish;  although  when  first  finished 
the  surface  may  be  fairly  smooth,  with  wear  it  soon  becomes  granular. 
Some  of  them  are,  in  general,  less  irritating  to  tooth  tissue  than  metal- 
lic fillings,  and  this  is  one  of  the  most  important  considerations.  Oxy- 
phosphate of  copper  has  been  found  to  be  extremely  bland  when  used 
near  the  pulp,  or  even  in  contact  with  gum  tissue.  In  regard  to  the 
porous  structure,  this  is  capable  of  some  reduction  through  modifi- 
cation of  constituents. 

Turning  to  indications  for  the  use  of  cement:  At  present  the  oxy- 
chloride is  not  used  to  any  extent  as  a  filling  for  the  entire  cavity, 
because  of  its  speedy  disintegration,  and  the  irritating  character  of  the 
chloride.  Many  authorities  agree  in  indorsing  it  as  a  cavity  lining 
because  of  its  white  color,  its  density,  and  therapeutic  value.     It  should 


252  FILLING    MATERIALS. 

not  be  used  too  close  to  the  pulp,  because  of  the  irritation  likely  to 
result,  but  it  may  be  used  to  advantage  in  pulpless  teeth  for  the  larger 
portions  of  the  canals  and  to  fill  the  pulp  chamber. 

We  are  considering  then,  practically,  only  oxyphosphates  of  zinc 
and  copper.  Fillings  prepared  from  these  materials  are  spoken  of  as 
temporary,  it  being  implied  that  they  will  be  replaced  sooner  or  later 
by  more  nearly  permanent  ones.  While  this  is  correct,  we  must  not 
lose  sight  of  the  fact  that  some  teeth  will  never  be  filled  with  anything 
more  permanent,  i.  e.,  cement  seems  peculiarly  and  preeminently  to 
lend  itself  to  the  preservation  of  certain  teeth.  It  is,  par  excellence, 
the  material  for  use  in  all  cases  where  for  any  reason  no  adequate 
cavity  preparation  can  be  made  for  the  so-called  permanent 
fillings. 

It  is  also  indicated  in  some  other  cases:  those  of  very  old  people, 
and  those  of  younger  people  in  whose  teeth  caries  is  acute.  In  the 
latter  case  it  is  introduced  as  a  temporary  filling  in  the  true  sense  of 
the  term,  in  extending  the  usefulness  of  frail  or  deciduous  teeth. 

In  discussing  the  preparation  of  cements,  we  are  confronted  with 
the  large  and  insurmountable  trade-secret  proposition.  The  mere 
names  indicate  some  of  the  chief  ingredients;  but  of  the  various  methods 
of  production,  the  modifying  agents  used,  etc.,  we  have  very  little 
data.  As  it  comes  to  the  operator's  hand,  a  cement  is  made  up  of  a 
powder  and  a  liquid.  The  powder  of  the  oxychloride  of  zinc  is  com- 
posed chiefly  of  oxide  of  zinc,  calcium  oxide  being  often  added  to 
hasten  setting,  and  other  ingredients  to  obtain  certain  other  proper- 
ties, as  silicate  of  aluminum,  magnesium  oxide,  sodium  borate,  silex, 
powdered  glass,  etc. 

The  oxyphosphate  of  zinc  is  principally  composed  of  glacial  phos- 
phoric acid  and  zinc  oxide,  to  which  are  added,  for  the  purpose  of  in- 
creasing hardness  and  lessening  solubility,  several  foreign  ingredients, 
e.  g.,  sodium  phosphate  gives  the  liquid  a  glassy  consistence  in  hand- 
ling. A  chemical  analysis  of  cements  shows  the  following  impurities:* 
arsenic,  antimony,  lithium  phosphate,  cadmium  sulphide,  carbon, 
fluorhydric  acid,  nitric  acid,  sodium  carbonate,  powdered  glass,  silex 
and  water  glass,  sodium  borate,  magnesium  oxide,  magnesium  nitrate, 
sodium  phosphate,  silicate  of  alumina,  phosphate  of  alumina.  The 
fineness  of  the  powder  varies  not  only  with  different  makes,  but  occa- 
sionally with  different  lots  put  out  by  the  same  maker.  The  finer  it  is, 
the  quicker  it  sets. 

The  oxyphosphate  of  copper  is  composed  of  the  same  liquid  as 

*Dr.  J.  E.  Hinkins,  Dental  Cosmos,  Vol.  xliii,  p.  591. 


GUTTA-PERCHA.  253 

the  foregoing,  and  cupric  oxide,  with  or  without  addition  of  other 
metallic  oxides. 

The  preparation  of  cements  for  filling  cavities  is  not  very  difficult, 
but  some  care  is  necessary.  The  phosphoric  acid  has  a  tendency  to 
crystallize.  To  lessen  this,  Dr.  Ames  recommends  keeping  it  in  a  tele- 
scoping glass  cap  bottle,  instead  of  one  with  the  cork  fitting  within 
the  neck.  The  prime  requisite  in  mixing  is  thorough  spatulation. 
Powder  should  be  added  to  the  liquid  in  only  a  small  mass  at  a  time, 
and  before  use  the  mixture  should  attain  a  putty-like  consistency. 

In  the  case  of  oxyphosphate  of  copper,  a  creamy  mix  seems  to 
give  best  results.  It  should  be  needless  to  say  that  the  glass  slab, 
spatula,  and  other  instruments  used  in  handhng  cements  must  be 
scrupulously  clean  and  well  polished. 

Cements  vary  somewhat  in  their  working  qualities.  Hence,  good 
results  can  be  made  sure  of  only  by  more  or  less  experience. 

The  cavity  preparation  for  cement  fillings  is  simplicity  itself,  since 
the  adhesiveness  of  the  material  may  be  very  largely  depended  upon 
for  securing  the  filling  to  the  cavity  walls.  The  complete  removal  of 
caries  should  in  every  case  be  insisted  upon,  however.  In  inserting 
the  material,  one  must  remember  to  overfill  the  cavity,  and  to  use  as 
nearly  as  possible  even  pressure  from  all  points.  For  this  work  broad, 
flat  burnishers  are  usually  employed.  These  should  first  be  rubbed 
upon  an  oil-pad  to  prevent  the  cement  from  adhering  to  them.  The 
filling  should  then  be  left  thoroughly  to  crystallize  before  trimming, 
which  process  is  accomplished  with  chisels,  trimming  knives,  and  occa- 
sionally burs.  A  fairly  smooth  surface  may  be  had  by  the  aid  of  fine 
sandpaper  discs  or  strips. 

The  cement  operation,  with  proper  care,  may  be  made  a  very  suc- 
cessful one.  That  it  has  fallen  in  estimation  somewhat,  is  due  largely 
to  the  fact  that  the  apparent  ease  of  cavity  preparation  and  of  manip- 
ulation lend  themselves  to  charlatanism.  Used  by  skillful  hands 
in  the  proper  places,  cement  has,  in  spite  of  its  lack  of  durability,  a 
valid  claim  to  a  position  among  filling  materials. 

GUTTA-PERCHA. 

The  name  gutta  percha  is  applied  to  the  inspissated  juice  of  various 
plants  belonging  to  the  natural  order  Sapotacea.  The  term  is  of 
Malayan  origin,  guiia  signifying  gum,  and  percha,  the  species  of  tree 
from  which  the  gum  is  derived.  It  is  native  in  the  Malay  Peninsula, 
and  although  its  use  has  long  been  known  in  the  Orient,  even  back 
into  antiquity,  it  was  not  introduced  into  the  western  world  until  early 


2  54  FILLING    MATERIALS. 

in  the  last  century,  when  its  great  possibilities  in  the  realm  of  manufac- 
ture were  recognized.  It  was  taken  up  by  dentists  about  1850,  and, 
according  to  Dr.  J.  Foster  Flagg,  it  was  then  suggested  as  a  temporary 
stopping  for  frail  teeth,  and  was  recommended  for  its  ease  of  manip- 
ulation, its  non-irritating  and  non-conducting  character,  its  insolubil- 
ity in  the  fluids  of  the  mouth,  and  its  reasonable  resistance  to  attrition. 
He  further  asserts  that  with  it  he  could  make  better  fillings  in  certain 
places  than  with  gold.  Various  modifications  of  it  were  introduced 
better  to  meet  the  dentist's  requirements.  But  the  difhculties  attend- 
ing its  manipulation,  its  non-resistance  to  attrition,  and  the  gradual 
gain  of  cement,  have  lessened  its  use.  Lastly,  the  introduction  of 
copper  oxyphosphate  has  almost  crowded  it  out  as  a  filling  for  the  entire 
cavity. 

The  properties  of  gutta-percha  are  its  decidedly  low  conductivity, 
its  blandness,  or  non-irritating  character,  its  agreeable  color,  and  its 
insolubility.  It  lacks  hardness,  even  when  foreign  substances  are 
introduced  to  increase  this  property.  Its  contraction  on  cooling  is 
also  an  objection,  as  is  also  its  more  or  less  porous  structure.  It  is 
insoluble  in  the  fluids  of  the  mouth;  it  can  be  reasonably  well 
adapted  to  cavity  walls;  it  changes  in  form,  notably  by  contraction;  it 
does  not  resist  attrition;  its  color  is  not  objectionable  and  is  easily 
modified;  it  is  the  best  material  we  have  for  non-conductivity;  it  is  not 
so  easy  of  manipulation  as  cement;  it  takes  no  polish  at  all. 

Gutta-percha  is  indicated  wherever  a  perfect  non-conductor 
is  needed;  but  as  it  cannot  be  used  in  any  place  where  it  will  be  sub- 
jected to  attrition,  it  is  decidedly  limited  in  its  application.  It  is 
especially  applicable  to  the  filling  of  small  pulp  canals  in  pulpless 
teeth. 

Commercial  gutta-percha  is  prepared  by  boiling  and  purifying  in 
a  number  of  ways.  When  nearly  pure,  it  is  of  a  grayish-white  color 
which  can  be  modified  as  desired.  For  dental  uses  the  pink  base 
plate  gutta-percha  seems  to  be  best.  It  is  colored  by  means  of  sulphide 
of  mercury. 

Its  successful  use  involves  considerable  skill.  It  must  be  heated 
until  soft  enough  to  permit  of  its  being  adapted  to  the  cavity  walls. 
In  this  process  it  must  never  come  in  contact  with  the  open  fiame. 
Various  devices  are  employed  for  heating,  such  as  porcelain  trays  to 
be  held  over  the  flame,  or  sand-bath.  If  overheated  it  is  ruined. 
Ordinarily  the  instruments  used  are  fiat  burnishers  which  should  be 
warmed  and  oiled.  The  cavity  should  have  some  retention  form, 
and  it  is  also  well  to  coat  the  cavity  walls  with  oil  of  cajeput  or  eucalyp- 


COMBINATION    FILLINGS.  255 

tus.  Dr.  Black  remarks  that  these  oils  take  strongly  to  cavity  walls, 
and  also  slightly  dissolve  the  surface  of  the  gutta-percha,  hence  their 
value. 

The  material  is  packed  piecemeal  into  the  cavity,  or  en  masse, 
care  being  taken  to  insure  thorough  adaptation.  One  should  guard 
against  obtaining  too  much  surplus,  for  gutta-percha  does  not  lend 
itself  so  well  to  trimming  and  finishing  as  do  other  materials,  although 
surplus  can  always  be  removed  by  the  aid  of  a  warmed  burnisher. 
Or,  when  it  has  sufhciently  hardened,  it  can  be  trimmed  with  thin, 
sharp  trimming  knives,  always  cutting  from  center  to  periphery. 

That  gutta-percha  has  possibilities  is  undoubtedly  true.  It  will 
in  all  probability  be  continued  in  use  for  some  time  to  come.  But, 
if  personal  opinion  were  not  out  of  place,  we  might  close  this  discus- 
sion by  observing  that  the  attitude  of  the  dental  world  seems  to  the 
present  writer  to  be  that  gutta-percha  as  a  filling  material  for  the 
entire  cavity,  all  things  considered,  is  distinctly  altered  since  the  virtues 
of  copper  oxyphosphate  have  been  fully  made  known. 

COMBINATION  FILLINGS. 

The  term  "combination  fillings"  has  been  made  acceptable  by 
usage,  although  it  is  not  in  all  cases  strictly  accurate. 

The  fact  that  no  one  material  possesses  all  the  virtues  desired, 
together  with  other  reasons,  as,  for  instance,  the  greater  ease  with  which 
particular  parts  of  the  same  cavity  lend  themselves  to  particular  ma- 
terials, have  led  to  frequent  indication  of  more  than  one  material  for 
the  filling  of  the  same  cavity.  A  few  of  these  will  be  taken  up  for 
discussion,  although  it  must  be  remembered  that  endless  combinations 
may  be  made,  according  to  the  necessities  of  the  case,  and  the  ingenuity 
of  the  operator. 

Platinum  and  gold  are  used  together,  chiefly  for  resulting  color 
and  density.  Platinum  is  bluish  silver-white  in  color.  Its  specific 
gravity  is  21.46.  The  color  of  the  combination  varies  between  light 
and  dark  gray,  depending  upon  the  quantity  of  platinum  used.  This 
platinum-gold  combination  withstands  attrition  better  than  gold 
alone.  For  esthetic  reasons  it  is  indicated  in  cases  when  patients 
are  of  dark  complexion.  It  is  also  desirable  when  more  density  is 
sought  than  gold  alone  can  supply. 

Platinum-gold  for  filling  is  used  in  the  forms  of  folds  of  both  metals, 
of  platinized  gold  folds,  and  of  platinum  and  gold  foil.  It  is  best  not 
to  use  it  for  the  entire  cavity,  a  surface  of  this  composition  being  quite 
sufiicient.     Generally  speaking  it  is  manipulated  in  the  same  manner 


256  FILLING    MATERIALS. 

as  gold  alone;  but  a  little  more  care  is  called  for  in  annealing  and  con- 
densing. That  is,  it  is  easily  overannealed,  and  a  small  condensing- 
area  plugger  point  should  be  used  and  moved  only  its  own  width  each 
time,  thus  insuring  thorough  condensation.  It  may  be  worth  nothing 
that  this  serviceable  combination  of  platinum  and  gold  has  of  late  been 
replaced  largely  by  the  porcelain  and  gold  inlays — the  porcelain  inlays 
chiefly  in  the  anterior  teeth,  and  the  gold  in  many  cases  where  great 
surface  is  to  be  restored  for  the  purpose  of  resisting  attrition. 

The  properties  of  gold  and  tin  have  already  been  considered. 
Tin  has  been  used  to  fill  part  of  a  cavity,  the  finishing  of  which  is  done 
with  gold.  Tin  was  largely  applied  in  proximal  cavities  to  cover  the 
gingival  wall,  in  the  same  manner  as  non-cohesive  gold;  but  this  opera- 
tion is  practically  discontinued,  owing  to  what  seems  to  have  been  a 
dissolution  of  the  tin 

One  method  of  preparing  tin  in  this  connection  is  to  take  it  in  sheet 
form,  superimpose  it  upon  a  sheet  of  gold,  cut  to  desired  widths,  and 
make  into  cylinders,  as  described  under  "  Gold."  A  few  operators 
use  this  combination  in  occlusal  cavities  in  deciduous  teeth,  and  in 
the  gingival  third  of  bicuspids  and  molars  in  the  adult  teeth  to  a  limited 
extent. 

It  is  handled  in  every  respect  like  non-cohesive  gold.  It  is  undoubt- 
edly true  that  this  gold- tin  filling  may  conserve  certain  teeth;  but  re- 
cent investigation  has  led  to  the  improvement  of  amalgam  and  its 
consequent  preferment  over  the  gold-tin  combination  in  many  cases 
where  the  latter  might  formerly  have  served.  Also,  in  the  gingival 
portion  of  cavities  there  seems  to  be  an  increase  in  the  use  of  non-cohe- 
sive gold  alone;  so  that,  on  the  whole,  the  outlook  for  this  combination 
is  not  the  most  encouraging. 

The  gold  and  amalgam  combination  is,  at  times,  of  great  value, 
amalgam  being  used  either  to  fill  inaccessible  parts  of  cavities,  as 
below  the  gingival  line,  or  merely  to  lessen  the  bulk  of  gold  in  very 
large  cavities.  In  complex  cavities  it  is  often  admissible  to  fill,  for 
instance,  a  disto-occlusal  cavity  with  amalgam,  and  the  mesio-occlusal 
with  gold,  making  a  step  into  the  amalgam. 

Gold  and  Cement. — Besides  using  the  cement  for  its  inherent  vir- 
tues, it  is  also  employed  to  lessen  the  bulk  of  gold  in  large  cavities  and 
in  pulpless  teeth. 

The  amalgam  and  cement  combination  is  used  similarly  to  the  fore- 
going. Cement  is  also  used  in  amalgam  operations  to  strengthen 
weak  walls,  in  which  case  it  practically  becomes  a  cavity  lining. 
Frail  teeth  can  often  be  thus  preserved  for  a  remarkably  long  period. 


COMBINATION    FILLINGS.  257 

Cement  and  Gutta-percha. — Owing  to  the  fact  that  gutta-percha  is 
not  soluble  in  the  fluids  of  the  mouth,  it  can  be  used  in  the  gingival 
portion  of  proximo-occlusal  cavities,  cement  being  employed,  since  it 
is  somewhat  denser,  for  finishing  the  rest  of  the  cavity.  In  general, 
it  is  not  advisable  to  let  metallic  fillings  rest  upon  gutta-percha,  owing 
to  lack  of  firmness  in  the  latter;  but  a  cement  intervening  will  afford 
the  proper  support. 

It  is  difficult,  if  not  impossible,  to  acquire  from  a  text-book  the  art 
of  filling  teeth,  be  the  text  ever  so  explanatory  and  complete  in  detail. 
Theory  must  be  supplemented  by  practice.  To  strike  an  even  balance 
in  this  respect  is  a  task  of  some  proportions.  In  filling  teeth,  we  imi- 
tate the  work  of  others.  Possibly  we  perfect  a  detail  here  and  there, 
make  a  new  discovery,  or  improve  a  method.  The  imitative  aspect 
of  the  profession  predominates,  however.  But  this  should  not  dis- 
courage us.  All  told,  the  world  we  live  in  is  an  imitative  one,  the 
absolutely  new  things  discovered  from  decade  to  decade  being  very 
few  indeed. 

Although  his  technique  may  have  been  revolutionized,  the  art  of 
the  sculptor  has  not  changed  since  Phidias  wrought  upon  the  Parthenon 
or  that  unknown  and  remoter  hand  carved  the  Sphinx's  features  in  the 
Valley  of  the  Nile.  The  bases  of  the  arts  do  not  shift  with  the  years; 
that  which  is  of  permanent  value  rests  upon  solid  foundations  like 
those  of  the  Sphinx  or  the  Pyramids  amid  their  waste  of  unsteady  soil. 
That  which  is  good  abides,  and  our  own  virtues  may  be  measured  ac- 
cording to  the  degree  in  which  we  show  ourselves  appreciative  of  the 
virtues  of  those  who  have  laid  our  professional  foundations. 

We  might  say  that  we  have  now  reached  a  certain  stage  of  perfec- 
tion in  the  preparation  of  cavities  in  teeth,  and  also  in  filling  them  with 
gold  and  other  materials.  Such  advancement  as  has  been  made  should 
be  rigidly  maintained.  We  should  not,  however,  be  content  to  rest  upon 
achievements.  We  must  keep  the  mind  receptive  to  possibilities,  and 
the  hand  pliant  and  supple  to  slowly  evolved  technical  inventions. 

We  have  often  seen  and  heard  emphatic  statements  from  operators 
to  the  effect  that  gold  is  the  ideal  and  only  fiUing  in  all  cases,  and  that 
they  use  nothing  else.  Such  statements  are  misleading  to  beginners 
who  many  times  take  them  too  seriously.  Experience  soon  teaches 
that  one  cannot  successfully  adapt  gold  to  all  cavities.  But  the  ques- 
tion, "what  is  the  best  filling?",  implying  that  one  material  for  all 
cases  is  possible,  will  often  be  heard  from  both  scientific  and  unscien- 
tific people.  Of  course,  the  question  cannot  be  answered  as  it  is  put. 
The  whole  of  the  foregoing  chapter  demonstrates  this.  An  attempt 
17 


258  FILLING    MATERIALS. 

at  least  has  been  made  to  elucidate  the  fact  that  any  one  of  our  materials 
is  the  best  one  for  the  special  uses  to  which  experience  has  taught  us 
its  properties  have  peculiarly  adapted  it. 

But  supposing  that  we  were  actually  limited  to  a  choice  of  one 
kind  of  material.  In  that  case  we  might,  perhaps,  choose  what,  in 
dental  parlance,  is  known  as  the  gold  inlay — cemented  into  the  cavity. 
A  discussion  of  this  appears  in  Chapters  XIV,  and  XVII.  This  sup- 
position, although  quite  imaginary,  tempts  speculation. 

Each  material  should  receive  the  highest  possible  attention  from 
the  operator  as  it  comes  into  his  experience.  The  object  should 
always  be  to  perfect  oneself  in  the  intelligent  application  and  manipu- 
lation of  materials;  and  this  can  best  be  done  by  regarding  each,  as 
it  is  indicated,  as  the  ideal.  This,  indeed,  it  is,  when  once  its  prop- 
erties are  found  to  harmonize  with  the  needs  of  the  case  under  treat- 
ment. 

In  closing,  perhaps  it  is  well  to  reii^erate  that  increase  in  technical 
proficiency  is  stimulated  if  accompanied  by  growth  in  a  general  under- 
standing of  the  eternal  fitness  of  things — an  appreciation  of  propor- 
tions and  harmonies,  not  only  in  our  own  specialized  branch  of  the 
great  world  of  science  and  art,  but  in  all  that  we  can,  by  industrious 
study,  bring  from  that  world  within  the  range  of  our  intellect.  The 
whole  world  of  artistic  endeavor — literature,  music,  design,  painting, 
sculpture — every  division  of  the  industrial  and  liberal  arts — teems 
with  lessons  for  the  worker  in  so  exacting  and  delicate  a  profession  as 
that  of  dentistry.  "It  is  all  triumphant  art,  but  art  in  obedience  to 
laws."  Dentistry  itself,  regarded  in  its  true  light,  must,  in  the  minds 
of  intelligent  operators,  come  to  be  regarded  as  not  the  least  among 
modern  arts  and  sciences. 

For  one  who  acknowledges  allegiance  to  this  broader  supremacy,  the 
practice  of  our  profession  should,  so  far  from  narrowing  a  man's  powers, 
continually  expand  them,  and  afford  more  and  more  intellectual 
satisfaction  as  he  progresses  towards  the  ultimate  ideal  of  perfection. 


CHAPTER  XIII. 
THE  USE   OF  THE  MATRIX  IN  FILLING  TEETH. 

BY  GARRETT  NEWKIRK,  M.  D. 

Matrix — Definition  of;  Standard  Dictionary:  "That  which  con- 
tains and  gives  form  to  anything:  as  a  plaster  matrix  for  a  cast." 
From  mater  (mother).  The  term  is  used  in  connection  with  descrip- 
tive anatomy,  geology,  biology;  also  applied  to  forms  for  stamping 
coins,  medals,  types,  etc.  Pronunciation,  ma'-trix  or  mat'-rix.  PL, 
mat'-ri-ces  or  ma'- trices.  "In  dentistry — a  strip  used  as  a  dam  in 
filling  side  cavities." 

It  will  be  observed  that  the  primary  use  of  the  matrix  is  that  of 
giving  form  to  a  new  structure;  in  nature  to  a  growth,  m  art  or  me- 
chanics to  a  building  or  product.  In  general  the  term  apphes  to  a 
product  which  is  entirely  new,  a  coin  or  medal  or  die.  In  dentistry 
we  have  a  modified  apphcation  of  the  term  in  that  the  matrix  is  used 
for  the  restoration  of  pre-existing  forms  that  have  been  to  a  greater  or 
less  extent  broken  down. 

The  term  "filling,"  as  usually  employed,  does  not  fully  express  our 
meaning.  It  is  commonly  said  by  the  dentist  that  he  has  "filled"  a 
tooth,  as  if  the  tooth  were  only  a  hollow  form,  a  capsule,  a  membran- 
ous sac,  or  a  shell  like  that  of  a  cartridge.  The  incongruity  is  ob- 
vious. Simple  cavities  in  teeth  may  be  "filled,"  and  to  this  class  of 
cases  the  term  should  be  limited.  What  we  are  really  called  upon  to 
do  in  most  cases  is  to  build  up,  to  restore,  the  parts  of  a  structure  that 
have  been  lost.  This  we  do  with  a  substitute  material,  joining  it  as 
best  we  may  to  the  remains  of  the  natural  organ. 

We  may  liken  the  teeth,  if  we  will,  to  a  double  row  of  monuments. 
The  relation  of  these  monuments  is  such  that  they  are  inter-depend- 
ent. The  loss  of  one  is  felt  by  others.  Each  is  dependent  on  its 
fellows  for  its  own  true  position  and  usefulness.  These  monuments 
come  to  us  broken,  with  every  degree  of  injury,  demanding  repair  or 
substitution.  Some  are  like  trees  in  Africa  that  have  been  honey- 
combed by  the  insidious  white  ant.  Some  are  like  houses  half  torn 
away  by  a  cyclone  or  an  earthquake.     They  are  in  part  ruins. 

The  restoration  of  these  monuments  in  proper  form  and  of  material 
to  endure  is  no  simple  problem.     No  two  are  quite  alike,  their  forms 

259 


26o  THE    USE    OF    THE    MATRIX    IN    FILLING    TEETH. 

are  almost  infinitely  various.  There  arc  no  plane  surfaces.  The  study 
is  one  of  curved  lines. 

The  mechanical  matrix  is  a  temporary  wall,  placed  for  the  support 
of  building  material  that  is  more  or  less  soft  and  yielding.  A  familiar 
example  is  that  of  a  board  employed  in  the  making  of  a  concrete  walk, 
which  holds  the  material  in  form  till  it  hardens. 

The  use  of  the  dental  matrix  is  fourfold: 

First,  to  serve  as  a  wall  of  resistance,  so  that  under  pressure  the 
building  material  may  be  thoroughly  condensed  and  joined  to  the 
tooth.  Second,  to  give  the  general  shape  of  restoration,  with  a  suffi- 
cient excess  of  material  for  finish  and  form.  Third,  in  cases  where 
plastic  materials  are  used  that  require  time  for  hardening  and  the 
matrix  is  kept  in  place  till  the  new  body  has  become  fixed  in  its  position. 
Fourth,  to  hold  back  the  interproximal  gum  tissue,  also  the  rubber 
dam,  from  the  cervical  border  of  a  cavity,  so  that  perfect  contact  of 
the  building  material  at  that  place  may  be  assured. 

MATERIALS  AND  FORMS  OF  THE  MATRIX. 

The  ideal  material  is  that  combining  the  greatest  strength  with 
thinness  and  spring  temper.  It  appears  to  be  the  consensus  of  opinion 
that  no  other  substance  possesses  so  many  excellencies  as  very  thin 
steel.  Ribbons  of  rolled  or  sheet  steel,  cut  in  suitable  lengths,  are 
best  adapted  for  general  use. 

For  the  first  really  practical  band  matrices  made  of  thin  steel,  the 
profession  is  indebted  to  Dr.  T.  W.  Brophy,  who  made  up  a  "set" 
with  an  ingenious  method  of  adaptation.  These  were  placed  on  the 
market  about  the  year  1886. 

Since  that  time  many  others  have  been  brought  out,  generally  under 
patent,  though  it  is  a  question  whether  the  original  Brophy  matrix  did 
not  cover  the  essential  features  of  most  of  them. 

Tinned  copper  or  German  silver,  rolled  thin,  are  practicable  ma- 
terials for  band  matrices,  being  easily  adapted  and  soldered  to  fit  spe- 
cial cases;  for  example,  where  the  greater  part  of  a  molar  or  bicuspid 
crown  is  to  be  built  up  with  amalgam,  and  where  it  is  necessary  to  have 
the  whole  of  the  base  encircled.  In  such  instances  it  is  not  possible  to 
obtain  the  best  supporting  matrix  without  making  one  especially  for 
the  case  in  hand. 

A  good,  practical,  special  band  matrix  may  be  made  of  the  softer 
materials  mentioned,  as  follows:  A  ribbon  of  proper  width  is  cut  half 
an  inch  longer  than  the  measured  circumference  of  the  tooth.  It  is 
passed  around  and  pinched  together  closely  with  pliers.     A  piece  of 


MATERIALS    AND    FORMS    OF    THE    MATRIX.  26 1 

binding  wire  is  wound  several  times  round  the  matrix  ends  at  the  line 
of  juncture,  and  twisted  tight.  The  projecting  ends  of  the  matrix 
band  are  now  bent  back  and  down  upon  the  band  proper  and  the  ap- 
pliance is  ready  for  use.  To  do  this  last  part  neatly  it  is  well  to  pass 
the  band  over  the  anvil  point  or  any  suitable  form  so  that  a  small  ham- 
mer may  be  used  for  the  flattening. 

Nearly  always  a  band  matrix  made  for  the  case  in  hand  should  have 
its  basal  circumference  smallest.  If  the  form  of  restoration  has  been 
right  the  body  enclosed  holds  the  matrix  fast,  and  it  must  needs  be 
disjointed  or  cut  for  removal.  A  continuous  band  matrix  to  be  used 
and  removed  entire  must  be  of  necessity  too  large  in  its  rootwise  circum- 
ference or  too  small  at  the  crown.  If  large  enough  to  provide  for  the 
proximal  contact  points  it  will  project  far  into  the  interproximal  space, 
leaving  a  gap  between  the  cervical  edge  of  the  matrix  and  the  tooth. 

Theoretically,  we  are  told  that  this  condition  is  to  be  overcome 
by  use  of  a  wedge  at  the  cervical  margin,  but  this,  particularly  with 
a  steel  matrix,  is  easier  said  than  done.  The  material  resists  stren- 
uously at  both  points,  and  the  resi:  tance  reaches  all  around  the  band. 
Usually  it  is  neither  accomplished  nor  attempted.  The  operator  fills 
the  matrix  as  it  is,  leaving  the  building  material  projecting  and  ragged 
at  the  base,  often  impinging  on  the  soft  tissues.  It  is  difficult  afterward 
to  remove  this  projection  with  chisels,  files  or  corundum  strips  without 
laceration  of  the  gums  and  pain  to  the  patient.  Therefore,  it  is  very 
important  that  the  matrix  in  its  introduction  should  pass  close  to  the 
tooth,  between  the  hard  and  soft  tissues,  never  impinging  on  the  latter. 
It  cannot  be  forced  down  midway  in  the  interproximal  space  and 
afterward  wedged  forward  to  place  without  injury.  It  should  go  to 
its  proper  position  at  the  first. 

Any  sort  of  band  matrix,  continuous  or  jointed,  whatever  may  be 
its  merits  has  one  disadvantage.  It  comes  short  of  the  ideal  in  that 
it  requires  the  use  of  two  interproximal  spaces.  This  involves  often 
difficulty  of  adjustment  with  loss  of  time,  both  in  the  putting  on  and 
taking  off;  and  the  extra,  second  space  is  taken  where  all  available 
room  is  needed  on  the  side  to  be  built  up.  It  is  an  advantage  to  have 
the  sound  side  of  the  tooth  crowded  against  its  next  neighbor  with 
nothing  between  them.  This  was  long  recognized  as  a  consummation 
to  be  wished,  but  it  seemed  necessary  that  in  general  the  matrix  must 
be  continuous  around  the  tooth  to  insure  a  rigid  support. 

It  seems  to  the  writer,  however,  that  by  the  use  of  the  "Ivory" 
matrices  and  their  accompanying  clamps,  encroachment  on  the  second 
space  may  be  avoided  in  the  great  majority  of  cases.     Just  as  the 


262 


THE    USE    OF   THE    MATRIX    IN    FILLING    TEETH. 


"Perry"  separator  gets  resistance  on  the  inclined  planes  of  the  teeth 
instead  of  their  disto- median  axes,  so  the  "Ivory"  matrix  clutch  utilizes 
the  inclined  planes  of  the  sound  portion  of  the  tooth  to  hold  the  matrix 
of  restoration.  The  principle  of  the  instrument  is  simplicity  itself, 
and  the  mechanism  highly  ingenious. 

Of  continuous  hand  matrices — i.  e.,  those  that  go  round  the  tooth 
far  enough  to  occupy  two  interproximal  spaces — there  have  been  many 


Fig.  235. — Crenshaw's  Matrix. 


forms  invented  and  placed  on  the  market;  some  of  them  patented.  Cuts 
are  reproduced  here  of  the  "  Crenshaw,"  quite  popular  in  the  East,  and 
the  "Hiniker,"  in  general  use  on  the  Pacific  Coast. 

There  are  others,  any  one  of  which  may  be  of  value,  when  ruled  by 
skillful  hands. 

A  form  of  appliance  that  has  been  widely  advertised  and  recom- 
mended is  that  which  we  may  style  the  "double"  matrix,  consisting 


THE    "hand"    matrix. 


263 


practically  of  two  segments  backed  together  and  used  for  building  up 
the  disto-occlusal  wall  of  one  tooth  and  the  mesio-occlusal  of  another 
at  the  same  time.  Certainly  the  principle  of  such  an  operation  is  not 
just  right.  Such  restorations  it  seems  to  the  writer  should  be  made 
separately — one  at  a  time;  for  the  two  teeth  are  not  immobile — each 
moves  slightly  with  any  exercise  of  force  upon  it.  The  matrix  should 
be  firmly  fixed  to  the  tooth  that  is  being  operated  upon.     In  the  in- 


FlG.  236. — Hiniker  matrix. 

sertion  of  the  single  "filling"  the  tooth  and  the  material  move  together 
as  one  body,  and  the  latter  is  in  no  wise  disturbed.  With  two  teeth  at 
once,  each  possessing  independent  motion,  this  cannot  hold  true  as 
the  material  is  likely  to  be  in  some  degree  disturbed. 

THE  "HAND"  MATRIX. 

This  instrument  consists  of  a  short,  thin  blade,  continuous  with 
a  shank  and  handle.  It  is  a  valuable  instrument  in  certain  places 
where  the  band  matrix  is  hardly  applicable.  It  is  specially  useful 
for  giving  form  to  fillings  of  cement  or  gutta-percha,  and  not  infre- 
quently for  amalgam  restorations.  Such  a  matrix  may  be  readily  made 
by  the  dentist  himself  out  of  any  discarded  instrument  that  has  a 
sufficient  body  of  steel  for  the  blade — a  spatula  or  wide  chisel  for  ex- 
ample. The  secret  of  success  in  getting  the  desirable  tough  spring 
temper  consists  in  persistent  hammering  with  the  avoidance  of  high 
heat.  It  may  be  added  also  that  any  other  than  the  finest  of  files 
should  not  be  used  in  dressing  down  the  blade  to  the  required  thinness. 

For  use,  with  everything  in  readiness  for  quick  manipulation  of  the 
building  material,  the  matrix  blade  is  placed  in  position  and  held  by 


264  THE    USE    OF    THE    MATRIX    IN    FILLING    TEETH. 

the  left  hand  of  the  operator.  It  is  seldom  that  an  assistant  can  man- 
age it  as  well.  The  handle  is  given  a  strong  twist,  so  that  the  rootward 
edge  is  held  firmly  up  to  the  cervical  margin  of  the  cavity.  The  op- 
posite edge  is  held  with  equal  firmness  against  the  crown  of  the  ap- 
proximating tooth.  If  either  or  both  of  the  teeth  are  at  all  movable  a 
considerable  separation  may  be  obtained  by  this  steady  twist  of  the 
handle.  A  sense  of  firm  resistance,  too,  will  be  experienced  while 
pressing  the  "filling"  material  home.  The  separation  obtained 
should  be  equal  at  least  to  the  thickness  of  the  matrix,  so  that  when 
it  is  withdrawn  there  will  be  sufficient  fullness  of  material  at  the  "con- 
tact" point.  For  restoring  the  disto-occlusal  walls  of  a  short  crowned 
second  molar,  where  it  is  sometimes  impracticable  to  apply  the  rubber 
dam,  and  the  work  should  be  done  quickly;  and  for  incisors  in  making 
large  restorations  with  cement,  the  hand  matrix  is  a  very  useful  instru- 
ment. 

A  FEW  DETAILS  AS  TO  MANIPULATION. 

Success  with  the  matrix  often  depends  very  much  on  previous 
preparation.  Deep-seated  cavities  are  frequently  bordered  by  swollen, 
sometimes  overhanging  gums.  It  is  nearly  always  better,  after  a  free 
opening  and  more  or  less  of  preparation,  to  let  these  carry  a  filling 
of  gutta-percha  for  some  days.  It  is  not  unusual  with  the  writer  to 
have  in  one  mouth  several  of  these  gutta-percha  filled  cavities  waiting 
for  the  matrix  and  restoration. 

Before  placing  the  matrix  for  an  operation,  if  there  is  any  doubt 
of  its  fitness  it  should  be  tried  in  tentatively,  to  ascertain  whether  it 
will  pass  as  it  should,  close  to  the  tooth  wall  and  not  upon  the  gum. 
Sometimes  an  ill-fitting  matrix  may  be  fairly  adapted  by  pinching  in 
the  cervical  edge  with  pliers.  The  Ivory  matrices,  however,  are  so 
shaped  and  may  be  so  inclined  in  their  introduction  that  they  go  to 
the  right  place  easily  in  most  cases. 

INTRODUCTION  AND  MANAGEMENT. 

It  is  commonly  advised  by  experts  that  as  a  rule  the  matrix  should 
not  be  completely  tightened  at  the  beginning,  but  only  after  the  inser- 
tion of  a  third  to  one-half  of  the  filling.  Without  doubt  we  may  say 
that  very  many  operators  do  not  take  sufficient  pains  with  that  same 
first  one-third.  Of  amalgam  altogether  too  much  is  likely  to  be  placed 
in  the  cavity  at  the  start.  Smaller  pieces  should  be  introduced  at  first 
and  thoroughly  condensed  with  smooth  instruments  all  along  the 
cervical  wall  and  its  junction  with  the  matrix.  This  takes  so  much  time 
that  often  with  quick-setting  amalgam  a  second  and  third  "mix"  may 


REMOVAL.  '  265 

be  required  to  complete  the  operation.  Sometimes  with  extra  dry  alloy 
one  may  use  a  mallet  with  good  effect,  in  addition  to  hand  pressure. 

In  the  second  half  or  last  third  of  the  filling,  whatever  the  material 
employed  may  be,  enough  force  should  be  exerted  against  the  matrix 
to  induce  separation  of  the  teeth  by  a  space  not  less  but  more  than 
the  thickness  of  the  band.  If  the  teeth  have  been  prepared  by  gutta- 
percha wedging,  as  above  suggested,  this  necessary  crowding  apart 
is  an  easy  matter.  As  stated  before,  there  ought  to  be  an  excess  of 
the  new  material  to  allow  for  final  shaping,  and  there  ought  to  be  like- 
wise a  separation  of  the  teeth  beyond  the  normal  at  the  completion 
of  the  filling.  This  will  permit  the  final  contact  point  to  come  slightly 
below  and  away  from  the  border  of  the  occlusal  surface,  otherwise 
it  will  be  a  mere  edge  continuous  with  the  occlusal  surface,  and  not 
the  rounded,  finished  knuckle  of  nature's  plan. 

There  would  be  an  improvement  at  this  point,  no  doubt,  if  the 
operator  would  take  the  pains  to  make  in  each  matrix  a  sufficient  con- 
cavity with  contour  pliers,  to  bring  the  filling  nearer  the  ideal  form. 
As  it  is,  with  any  common  form  of  matrix,  the  filling  as  the  band  leaves 
it  shows  only  a  straight  profile  from  the  cervical  to  the  occlusal  border. 
The  contoured  matrix,  however,  used  for  a  plastic  filling  could  not  be 
removed  at  once  without  disturbing  the  form.  It  would  need  to  re- 
main till  the  material  had  set. 

REMOVAL. 

With  amalgam  there  are,  as  we  know,  advantages  to  be  gained  by 
leaving  the  matrix  in  siti*  till  the  material  has  become  hard;  indeed, 
it  is  very  necessary  to  do  so  in  cases  where  reconstruction  has  been 
extensive  and  the  basal  support  relatively  weak.  But,  on  the  other 
hand,  there  is  something  to  be  gained  by  immediate  removal.  This 
is  one  of  the  advantages  of  an  open  matrix  like  the  "Ivory."  When 
the  clutch  is  loosened  it  "lets  go."  It  is  readily  straightened,  being 
flexible,  and  touches  the  tooth  or  filling  only  at  the  point  of  contact. 
With  the  slightly  oiled  surface  a  band  should  always  have  it  is  easily 
removed  by  gentle  manipulation.  Then,  with  a  properly  shaped  blade, 
half  knife,  half  burnisher,  a  trimming  and  close  condensation  of  the 
material  may  be  made  all  along  the  edges.  I  believe  that  perfect  bor- 
ders can  be  made  in  this  manner  with  greater  certainty  than  is  possible 
otherwise. 

EMPLOYMENT  OF  THE  MATRIX  FOR  GOLD  RESTORATIONS. 

We  know  what  the  bevel  of  a  margin  should  be  for  the  reception 
of  gold.     We  know  that  for  the  proper  condensation  of  gold  over  such 


266  THE    USE    OF   THE   MATRIX    IN    FILLING    TEETH. 

a  margin  the  instrument  should  have  free  play;  and  we  know  that  it 
is  well  to  have  visual  as  well  as  mechanical  access  to  the  area  involved. 
There  is  no  denying  that  the  matrix  does  shut  off  vision  along  the  very 
lines  where  seeing  is  desirable.  If  we  permit  a  loose  adjustment  of  the 
matrix  in  order  to  see  the  margins  it  is  of  little  use.  It  is  likely  also  to 
crowd  upon  the  gum  tissue,  to  draw  the  edge  of  the  dam  from  the  tooth 
and  induce  leakage.  If  closely  adjusted,  the  matrix  forms  with  the 
beveled  margin  a  sharp,  acute  angle,  into  which  the  gold  must  be  forced 
accurately  and  condensed,  else  there  is  left  an  imperfect  line  of  union. 
We  cannot  be  as  certain  with  as  without  the  matrix  that  the  gold  is 
being  adapted  accurately  at  every  point.  Undoubtedly  there  are 
operators  who  have  learned  with  much  of  patience  and  experience  to 
obviate  the  risk;  who  can  apply  the  matrix  over  a  deep-seated  cavity 
and  make  a  good  restoration  from  start  to  finish.  But  such  operators 
the  writer  believes  to  be  exceptional.  It  is  a  fact  of  experience  that  we 
are  often  called  on  to  renew  or  repair  fillings  that  have  been  so  inserted 
which  have  failed  at  the  cervical  or  cervico-lingual  or  cervico-labial 
borders;  and  we  find  others  that  are  spongy  or  pitted  or  grooved  in  those 
places.  Let  it  be  understood,  however,  that  after  a  substantial  body 
of  gold  has  been  placed  along  the  wall  and  angles  of  the  cavity,  then 
the  matrix  may  be  of  service  as  a  guide  to  the  general  form  of  building, 
especially  for  the  full  extension  and  thorough  condensation  of  the 
"knuckle"  at  the  contact  point;  and  possibly  the  work  may  be  done 
more  rapidly. 

If  one  is  determined  to  take  the  risk,  whatever  it  may  be,  of  using 
the  matrix  "from  start  to  finish"  for  contour  restorations,  he  must 
familiarize  himself  with  the  properties  and  manipulation  of  non-co- 
hesive gold.  It  is  the  chief  dependence  of  successful  operators  for 
the  basal  third  or  half  of  the  restoration. 

GUTTA-PERCHA  FILLINGS. 

For  the  insertion  of  these  the  matrix  has  a  well-defined  use.  Aside 
from  those  cases  wherein  it  is  necessary  to  crowd  away  the  gum  for  a 
subsequent  operation,  the  margin  of  a  gutta-percha  filling  should  be 
carefully  made  like  any  other.  Patients  often  suffer  discomfort  and 
sometimes  real  injury  from  carelessly  made  gutta-percha  fillings. 
It  is  better  to  make  a  filling  of  good  form  to  begin  with  than  to  crowd 
in  an  ill-defined  mass  to  be  trimmed  up  afterward,  and  for  this  purpose 
the  "hand"  matrix  is  usually  well  adapted. 


CHAPTER  XIV. 
INLAYS. 

BY  C.  N.  JOHNSON,  M.  A.,  L.  D.  S,,  D.  D.  S. 

The  Principle. — To  repair  a  carious  or  abraded  cavity  in  a  tooth 
by  the  inlay  method  the  operator  adapts  a  piece  of  heavy  foil,  either 
platinum  or  gold,  to  the  cavity  so  that  it  fits  perfectly,  thus  reproducing 
the  form  and  outline  of  the  cavity  in  metal;  and  in  the  matrix  so  formed, 
removed  from  the  mouth,  he  builds  a  filling  of  porcelain  or  gold  and 
cements  this  in  the  cavity.  In  the  more  recent  developments  in  gold 
inlay  work  a  wax  model  is  made  in  the  cavity,  and  this  is  reproduced 
in  gold.  The  principle  is  different  from  that  of  the  ordinary  filling, 
the  latter  being  adjusted  piece  by  piece  into  the  cavity  in  the  tooth, 
the  entire  operation  being  performed  in  the  mouth;  while  with  the 
inlay  much  of  the  work  is  done  outside  the  mouth  and  without  the 
necessity  of  the  patient's  presence.  This  is  a  very  great  advantage 
of  inlay  work  and  has  led  in  a  large  degree  to  its  popularity.  The 
relief  from  the  tedium  of  long  and  sometimes  painful  sittings  has 
been  a  source  of  great  satisfaction  not  only  to  the  patient  but  to 
the  operator  as  well.  There  is  less  nervous  tension  and  altogether 
a  greater  measure  of  comfort  in  doing  inlay  work  than  in  such  oper- 
ations as  large  gold  fillings,  and  this  phase  of  the  subject  has  appealed 
very  strongly  to  patients. 

INDICATIONS  FOR  THE  USE  OF  INLAYS. 

That  inlays  have  become  an  important  factor  in  reparative  proc- 
esses in  operative  dentistry  there  can  be  ncJ  question.  There  is  still 
some  difference  of  opinion  as  to  the  precise  range  of  their  applicability, 
but  for  certain  well-defined  cases  their  utility  is  no  longer  in  doubt. 
It  must,  therefore,  be  apparent  that  no  dentist  can  practice  to  the  best 
advantage  for  himself  and  his  patient  without  an  understanding  of  this 
work.  There  are  many  cases  of  aff'ected  teeth  that  can  be  better 
preserved  by  this  than  by  any  other  method.  In  cases  of  extensive 
decay  it  may  frequently  be  made  to  save  a  tooth  which  otherwise 
would  be  condemned  to  crowning,  and  on  general  principles  the 
longer  a  tooth  can  be  saved  without  a  crown  the  better  it  is  for  the 
patient, 

267 


268  INLAYS. 

From  the  nature  of  their  method  of  manufacture  inlays  are  restricted 
in  their  use  to  cavities  which  will  admit  of  the  matrix  or  wax  being 
inserted  and  removed  without  distortion,  or  cavities  which  may  be 
made  of  such  a  form  without  an  unwise  sacrifice  of  sound  tooth  tissue. 

Porcelain  inlays  are  indicated  chiefly  in  cavities  exposed  to  view 
in  talking,  laughing,  or  singing.  It  should  be  the  highest  aim  of  art 
in  dentistry  to  conceal  the  evidence  of  our  operations  from  public 
view,  and  the  conspicuous  display  of  gold  so  frequently  seen  in  the 
anterior  teeth  of  patients  speaks  of  a  lack  of  taste  which  is  something 
of  a  reflection  on  the  profession.  Fortunately  this  display  is  less 
prominent  than  formerly,  and  this  in  large  measure  is  due  to  the 
introduction  of  porcelain  inlay  work.  With  porcelain  an  operation 
may  be  made  which  is  not  conspicuous  at  conversational  distance 
from  the  patient,  and  in  some  instances  the  porcelain  may  be  shaded 
to  match  the  enamel  so  perfectly  as  to  defy  detection  even  on  reason- 
ably close  observation.  This  is  a  great  step  in  advance  so  far  as 
the  art  side  of  our  calling  is  concerned,  and  every  dentist  should  equip 
himself  to  take  advantage  of  it. 

But  this  work  has  its  limitations  which  should  be  recognized  by 
every  conscientious  operator.  The  physical  characteristics  of  porce- 
lain are  in  some  respects  very  much  against  its  extended  use,  particu- 
larly in  positions  where  the  stress  of  mastication  comes  forcibly  upon 
it.  Porcelain  is  brittle  and  will  fracture  easily.  It  is  therefore  contra- 
indicated  in  cases  where  the  filling  must  be  made  with  thin  margins 
or  in  small  bulk.  It  is  true  that  in  the  anterior  part  of  the  mouth 
where  esthetic  considerations  are  very  important  it  is  frequently 
justifiable  to  take  some  chances  of  its  fracture  and  place  it  in  positions 
of  prominent  exposure  even  with  some  risk  of  failure.  Patients  are 
often  willing  to  take  this  risk  for  the  sake  of  the  improved  appearance 
over  any  kind  of  a  metal  filling,  and  where  there  is  a  perfect  under- 
standing between  operator  and  patient  as  to  the  possibilities  of  failure 
porcelain  may  be  given  a  rather  wide  range  of  application  in  the 
anterior  teeth.  Porcelain  inlay  work  has  not  been  sufficiently  long 
in  general  use  to  afford  the  necessary  data  upon  which  to  base  reliable 
judgment  as  to  its  probable  permanence,  and  in  many  of  these  cases 
where  great  risk  was  apparently  taken  the  service  of  the  inlays  has 
been  surprisingly  satisfactory.  It  may  also  be  stated  that  in  many 
other  cases  where  the  same  care  has  been  exercised  in  their  manu- 
facture, and  where  conditions  would  seem  to  favor  their  utility  they 
have  proved  a  grievous  disappointment.  It  is  this  element  of  uncer- 
tainty with  inlays  which  has  made  many  of  our  conservative  practi- 


INDICATIONS    FOR    THE    USE    OF    INLAYS,  269 

tioners  look  with  disfavor  upon  the  work,  and  yet  their  demonstrated 
utility  in  so  many  cases  is  sufficient  to  argue  strongly  in  their  behalf. 

It  is  probably  true  that  much  of  the  failure  has  been  due  to  imper- 
fect methods  of  manipulation  and  to  a  lack  of  knowledge  of  the  under- 
lying principles  of  the  work,  as  well  as  to  faulty  technique  in  carrying 
it  out.  Another  uncertain  factor  has  been  the  cement.  This  material 
has  proved  itself  peculiar  in  its  behavior  under  various  conditions 
and  some  of  its  peculiarities  have  not  been  well  understood.  In 
addition  to  this,  much  of  the  cement  used  for  inlay  work  in  the  past 
has  been  made  for  fillings  and  for  cementing  crowns  without  regard 
to  the  peculiar  requisites  for  inlay  work.  Neither  have  the  correct 
principles  of  cavity  preparation  for  inlays  been  generally  recognized 
or  put  in  practice. 

In  short  the  work  has  had  to  pass  through  the  experimental  stage 
of  a  new  line  of  effort  and  has  suffered  accordingly,  but  these  factors 
of  failure  are  rapidly  being  eliminated  and  we  may  confidently  look 
forward  to  more  assured  success  since  the  principles  are  being  better 
understood  and  the  technique  systematized;  though  with  porcelain 
inlay  work  it  must  not  be  forgotten  that  it  will  always  have  the  one 
serious  limitation  of  friability  of  the  material  itself. 

Gold  inlay  work  has  a  much  wider  range  of  usefulness  so  far  as 
serviceability  is  concerned  than  porcelain  on  account  of  its  great 
strength,  and  it  should  be  used  quite  generally  wherever  inlay  work  is 
indicated  in  places  not  exposed  to  view.  Gold  may  be  made  to 
protect  frail  walls  of  enamel  if  necessary  and  the  material  itself  may 
be  extended  into  thin  margins  without  danger  of  fracture. 

To  specify  the  particular  classes  of  cavities  where  inlay  work  is 
indicated  and  draw  a  distinct  line  of  demarcation  between  the  indi- 
cations for  fillings  and  inlays  is  difficult,  owing  to  the  varying  con- 
ditions which  are  presented  in  different  cases.  The  preference  of  the 
patient  must  sometimes  be  considered,  though  it  is  not  well  to  allow  a 
whimsical  prejudice  to  influence  the  operator  to  do  a  certain  class  of 
work  under  conditions  where  it  is  manifestly  contra-indicated.  It 
may  be  said  in  general  that  porcelain  inlays  are  indicated  in  all  cavities 
exposed  conspicuously  to  view  in  cases  where  esthetic  considerations 
are  very  important,  such  as  cavities  in  the  labial  or  buccal  surfaces  of 
incisors,  cuspids  and  bicuspids,  cavities  in  the  proximal  surface 
of  those  teeth  where  there  is  much  exposure,  and  in  contour  operation 
involving  two  surfaces  where  a  display  of  gold  would  be  objectionable 

In  recent  years  the  use  of  silicate  cements  has  somewhat  displaced 
porcelain,  and  the  tendency  seems  constantly  in  that  direction.     The 


270  INLAYS. 

improvement  in  the  silicates,  and  the  more  satisfactory  appearance  of 
the  margins  of  such  fillings  over  porcelain  inlays  has  led  many  opera- 
tors to  practically  discard  porcelain  in  their  favor.  There  is  no 
question  that  a  more  artistic  filling  may  be  made  with  the  silicates 
than  with  porcelain,  but  so  far  as  wearing  properties  are  concerned 
the  former  cannot  be  compared  with  the  latter.  It  is  hoped  that 
with  the  constant  improvement  being  made  in  the  silicates  we  shall 
eventually  have  a  plastic  material  which  will  be  sufficiently  permanent 
to  render  the  somewhat  difficult  technique  of  making  porcelain  inlays 
less  necessary. 

Gold  inlays  are  indicated  in  large  restorations  in  bicuspids  and 
molars,  in  cavities  far  back  in  the  mouth  where  the  problem  of  insert- 
ing an  ordinary  filling  is  difficult,  and  cavities  in  the  buccal  surfaces 
of  molars  where  the  decay  has  extended  under  the  free  margin  of  the 
gum.  Employed  in  these  cases  gold  inlays  are  very  useful  and  may 
be  given  a  wide  range  of  service,  but  this  will  still  leave  a  large  class 
of  cavities  where  the  ordinary  filling  has  its  legitimate  field  and  where 
no  inlay  can  do  equal  service. 


CHAPTER  XV. 
PREPARATION  OF  CAVITIES  FOR  INLAYS. 

BY  C.  N.  JOHNSON,  M.A.,  L.  D.  S.,  D,  D.  S. 

When  inlays  were  first  introduced  the  general  impression  given 
the  profession  that  the  adhesive  properties  of  cement  could  be  relied 
upon  to  hold  the  inlay  in  place  irrespective  of  much  depth  to  the  cavity 
led  to  the  formation  of  cavities  too  shallow^  and  vi^ith  insufficient  atten- 
tion to  the  principle  of  mechanical  anchorage.  Inlays  should  be 
anchored  upon  the  same  general  mechanical  plan  as  fillings,  the  only 
difference  being  in  the  details.  It  will  of  course  be  recognized  in  the 
beginning  that  cavities  for  inlays  must  be  so  formed  that  the  matrix  or 
wax  may  be  lifted  from  the  cavity  without  distortion,  and  this  idea  being 
prominent  in  the  mind  of  operators  caused  them  in  many  instances 
to  make  the  walls  of  their  cavities  too  flaring,  with  the  orifice  much 
wider  than  the  interior.  This  resulted  in  attenuated  edges  to  the 
inlay  and  frequently  to  a  lack  of  definiteness  of  form,  leaving  the  cavity 
more  or  less  saucer-shaped.  This  is  wrong  in  principle  and  has 
quite  generally  proved  a  failure  in  practice.  Cavities  should  be  made 
with  some  depth  and  with  walls  so  formed  that  the  inlay  will  remain 
seated  without  tilting  or  rocking  under  pressure  even  before  it  has  been 
cemented. 

In  opening  up  cavities  it  is  true  that  there  are  many  cases  where  the 
orifice  must  be  quite  widely  extended  to  admit  of  entering  a  matrix  or 
wax  into  the  cavity  and  removing  it.  This  often  involves  cutting  much 
sound  tooth  tissue,  particularly  in  proximo-occlusal  cavities  in  bicuspids 
and  molars,  where  the  decay  in  the  proximal  surface  may  have  ex- 
tended much  wider  bucco-lingually  in  the  gingival  region  than  it 
has  nearer  the  occlusal  surface.  It  will  be  seen  at  once  that  to  fit 
a  wax  model  to  such  a  cavity  it  must  be  extended  bucco-lingually  very 
freely  at  the  point  where  the  proximal  surface  joins  the  occlusal  to 
bring  it  on  a  line  with  the  cavity  further  rootwise.  The  practitioner 
who  purposes  using  inlays  in  these  cases  must  have  the  will  to  cut 
quite  extensively,  and  there  are  many  instances  where  the  loss  of  sound 
tooth  tissue  is  so  very  great  that  the  discriminating  operator  will 
decide  upon  inserting  a  filling  instead  of  an  inlay.     This  is  one  factor 

271 


272  PREPARATION    OF    CAVITIES    FOR    INLAYS. 

in  the  choice  between  inlays  and  fillings  which  has  not  received  suffi- 
cient consideration.  While  it  is  true  that  in  the  preparation  of  cavities, 
whether  for  inlays  or  fillings,  we  are  frequently  called  upon  to  remove 
sound  tissue  for  better  access  to  the  cavity  and  to  establish  marginal 
outlines  at  points  where  recurrence  of  decay  will  not  take  place,  yet 
it  is  unjustifiabfe  to  sacrifice  large  portions  of  sound  tissue  in  locations 
of  practical  immunity  from  decay  in  order  to  bring  the  cavity  within 
the  requirements  for  inlay  work.  In  many  of  these  cases  a  filling  may 
be  inserted  to  better  advantage  and  with  less  injury  to  the  tooth. 

One  cardinal  principle  in  the  formation  of  cavities  for  porcelain 
inlays  is  that  they  should  be  so  shaped  if  possible  as  to  leave  no  thin 
margins  to  the  porcelain.  A  thin  margin  usually  means  a  fractured 
margin  in  a  short  time.  With  cavities  for  gold  inlays  the  exact  opposite 
is  true.  One  of  the  chief  virtues  of  gold  inlays  is  that  the  enamel 
margins  may  be  freely  beveled  and  the  gold  allowed  to  lap  over  them — 
a  relatively  thin  layer  of  melted  gold  being  sufficiently  strong  for 
ample  protection  to  the  enamel.  It  is  with  this  idea  in  mind  that  the 
following  detail  of  cavity  formation  for  the  different  classes  is  sug- 
gested. 

Cavities  in  the  labial  surfaces  of  incisors  and  cuspids,  and  the 
buccal  surfaces  of  bicuspids  and  molars.  The  first  essential  in  the 
preparation  of  these  cavities  is  to  open  the  cavity  freely  by  breaking 
down  all  enamel  undermined  by  decay.  The  axial  or  pulpal  wall 
should  be  made  perfectly  flat  so  that  the  inlay  will  have  a  definite 
seat  to  rest  upon.  This  is  conveniently  done  with  an  inverted  cone 
bur  stood  with  its  end  looking  toward  this  wall,  and  carried  laterally 
across  the  floor  of  the  cavity.  There  should  be  an  angle  formed 
between  the  axial  wall  and  the  surrounding  walls,  not  a  perfectly 
right  angle  so  as  to  leave  the  surrounding  walls  parallel,  but  very 
nearly  so.  If  these  walls  were  perfectly  parallel  it  would  manifestly 
be  impossible  to  fit  a  matrix  and  remove  it,  but  the  nearer  they  approach 
to  this  the  more  securely  will  the  inlay  be  anchored,  and  the  less  neces- 
sity for  relying  on  the  cement  as  an  adhesive  agent.  Cement  should 
be  used  in  the  capacity  of  a  sealing  material  between  two  joints  and 
not  as  a  glue  to  hold  the  inlay  to  the  cavity.  In  short  the  cavity  should 
be  so  formed  that  there  shall  be  some  frictional  retention  against  the 
surrounding  walls,  the  inlay  in  many  instances  going  to  place  with 
a  snap.  When  cavities  are  formed  along  these  lines  there  will  be 
less  trouble  from  inlays  dropping  out. 

It  might  be  imagined  that  the  fitting  of  a  matrix  to  such  a  cavity 
would  be  very  difficult  but  this  is  found  in  practice  not  to  be  so,  and 


PREPARATION    OF    CAVITIES    FOR    INLAYS.  273 

even  if  it  did  slightly  complicate  this  part  of  the  operation  it  would 
be  justifiable  on  account  of  the  greater  security  of  the  inlay. 

There  should  be  no  beveling  of  the  enamel  margins  for  porcelain 
except  as  the  slight  divergence  of  the  surrounding  walls  at  the  orifice 
of  the  cavity  forms  a  bevel.  In  the  use  of  the  inverted  cone  bur  for 
forming  the  axial  wall  if  the  sharp  angle  of  the  bur  should  undercut 
the  surrounding  walls  they  may  be  trued  up  wath  a  chisel  or  with  a 
fissure  bur  stood  with  its  end  looking  toward  the  axial  wall  and  cut- 
ting with  the  side  of  the  bur.  The  outline  of  a  cavity  formed  as  just 
indicated  is  shown  in  the  two  sections  of  an  incisor,  Fig.  237,  longi- 
tudinal, and  Fig.  238,  cross-section. 

In  bicuspids  the  form  of  the  axial  wall  is  sometimes  different 
from  this  on  account  of  the  difference  in  the  form  of  the  tooth.  If 
the  axial  wall  were  cut  perfectly  flat  in  some  cases  of  extensive  decay  it 
might  result  in  exposure  of  the  pulp  and  so  it  should  be  given  a  convex 


Fig.  237.       '  Fig.  238  Fig.  239.  Fig.  240. 

form  as  indicated  in  the  cross-section  of  a  bicuspid,  Fig.  239.  This 
form  facilitates  the  firm  seating  of  the  inlay  fully  as  well  as  the  flat 
form,  and  in  some  instances  furnishes  a  more  secure  anchorage. 

In  extensive  penetration  of  caries  where  the  cavity  runs  under  a 
strong  wall  of  overhanging  tooth  tissue  and  it  is  deemed  undesirable 
to  cut  this  wall  entirely  away,  it  may  be  permissible  to  excavate  the 
cavity  perfectly  and  fill  the  undercut  with  cement.  After  this  has 
become  hard  the  cavity  may  be  prepared  as  usual.  This  practice 
is  not  often  feasible  on  account  of  the  fact  that  ordinarily  when  decay 
undermines  a  wall  it  does  so  in  such  a  way  as  to  weaken  it  beyond  the 
possibility  of  retaining  it  with  safety. 

Upon  broad  surfaces  such  as  the  buccal  surfaces  of  molars  we 
frequently  find  decay  running  along  over  a  considerable  area  with 
little  penetration  into  the  tooth,  and  in  these  cases  if  the  cavity  is 
formed  on  correct  mechanical  lines  with  flat  seat  and  proper  angles 
it  need  not  be  made  very  deep.  But  an  inlay  for  such  a  cavity  should 
be  of  strong  material  and  it  is  usually  best  in  all  buccal  cavities  of 
molars  to  insert  gold  inlays  in  preference  to  porcelain. 
18 


2  74  PREPARATION    OF    CAVITIES    FOR    INLAYS. 

Simple  cavities  in  the  proximal  surfaces  of  incisors  and  cuspids. 
These  cavities  must  be  opened  sufficiently  to  the  labial  or  lingual  to 
admit  of  fitting  the  matrix,  and  it  is  therefore  necessary  to  cut  away 
one  of  these  walls  quite  freely;  though  the  ample  separation  of  the 
teeth  in  advance  of  the  operation  will  in  some  measure  dispense  with 
this  necessity.  The  same  provision  for  seating  the  inlay  firmly  in 
place  should  be  made  in  these  cavities  as  in  others  and  the  axial  wall 
should  be  made  as  flat  as  possible.  If  the  labial  wall  has  been  cut 
away  and  the  lingual  wall  remains  standing  with  sufficient  integrity 
to  admit  of  it  being  left,  there  should  be  an  angle  formed  between  it 
and  the  axial  wall,  and  even  where  the  lingual  wall  must'  be  removed 
it  will  be  found  possible  to  make  a  point  angle  in  the  gingivo-linguo- 
axial  region.  The  gingival  wall  should  be  made  at  nearly  right  angles 
with  the  axial  wall  and  almost  parallel  with  the  incisal  wall,  which 
should  also  join  the  axial  wall  at  an  angle,  so  that  the  inlay  will 
lock  between  the  incisal  and  gingival  walls  as  if  in  a  box.  Fig.  240 
illustrates  the  labial  surface  of  an  incisor  with  the  marginal  outline 
of  the  cavity  indicated,  and  the  dotted  lines  showing  the  interior  form 
of  the  walls. 

In  cases  where  there  has  been  much  breaking  down  of  the  lingual 
wall  with  a  strong  labial  wall  standing,  the  cavity  should  be  opened 
mostly  to  the  lingual  and  the  inlay  inserted  from  this  direction.  In 
these  cavities  an  angle  should  be  made  in  the  gingivo-labio-axial 
region  so  as  to  form  a  flat  seat  of  resistance  at  this  point,  which  will 
receive  most  of  the  stress  brought  to  bear  upon  such  an  inlay. 

Cavities  in  the  proximal  surfaces  of  the  anterior  teeth  involving 
the  incisal  angle.  These  cavities  present  a  more  difficult  problem 
for  porcelain  to  meet  than  any  of  those  where  porcelain  inlays  are 
indicated,  and  yet  their  exposed  positions  often  call  for  this  kind  of 
restoration.  It  is  therefore  necessary  to  study  very  carefully  the  forms 
that  shall  be  given  these  cavities  for  the  most  secure  anchorage  and 
the  greatest  strength  to  the  porcelain.  The  operator  must  individual- 
ize his  cavities  and  take  advantage  of  every  possible  opportunity 
presented  by  the  peculiarities  of  the  case  to  gain  depth  to  the  cavity 
and  bulk  to  the  inlay. 

It  will  usually  be  found  that  to  gain  security  of  anchorage  some 
form  of  step  must  be  made  in  the  incisal  region,  and  yet  there  are 
certain  cases  which  do  not  lend  themselves  readily  to  this  method 
of  treatment.  Ordinarily  the  step  is  made  by  cutting  across  the  incisal 
edge  at  right  angles  to  the  proximal  portion  of  the  cavity  making 
approximately  an  L  shape  to  the  inlay,  but  sometimes  it  is  not  ex- 


PREPARATION    OF    CAVITIES    FOR    INLAYS. 


275 


pedient  to  cut  away  the  angle  of  the  enamel  in  this  manner.  This  is 
particularly  true  of  those  cases  where  the  decay  has  involved  the 
lingual  surface  far  in  advance  of  the  labial  in  upper  incisors  leaving 
little  tissue  in  which  to  form  a  step.  It  is  also  true  in  some  instances 
where  there  has  been  a  simple  proximal  cavity  of  shallow  depth  in 
either  an  upper  or  lower  tooth  and  the  incisal  angle  has  fractured  off 
following  a  check  in  the  enamel  leaving  a  clean  sound  surface  of 
tissue  along  the  axial  wall  with  the  enamel  in  perfect  condition  in  the 
incisal  region.  These  are  cases  which  do  not  call  for  much  incisal 
exposure  to  stress  and  it  would  seem  too  radical  a  procedure  to  cut 
away  the  incisal  enamel,  besides  increasing  the  exposure.  If  the 
teeth  in  these  cases  are  well  separated  a  cavity  may  be  prepared  by 
cutting  a  shoulder  in  the  axial  wall  looking  toward  the  incisal  and 
about  one  and  one-half  millimeters  from  the  incisal  edge,  as  indicated 
in  Fig.  241.     This  should  be  supplemented  by  a  rather  deep  and  strong 


Fig.  241. 


Fig.  242. 


Fig.  243. 


anchorage  in  the  gingival  region,  and  if  the  teeth  are  sufficiently 
separated  the  inlay  may  be  slipped  into  place  laterally.  This  form 
of  anchorage  is  of  course  not  the  strongest  from  a  mechanical  point 
of  view  where  great  stress  is  exerted  on  the  inlay,  but  in  a  somewhat 
close  observation  of  many  cases  in  practice  it  has  proved  sufificiently 
satisfactory  to  recommend  its  use  in  the  class  of  cavities  indicated. 
Where  the  step  anchorage  is  employed  it  is  usually  best  to  shorten 
both  labial  and  lingual  plates  of  enamel  at  least  half  way  across  the 
incisal  edge  (Fig.  242,  labial  view) ,  though  this  is  not  invariable.  Some- 
times the  labial  enamel  may  be  left  standing  in  upper  incisors  provided 
sufficient  bulk  can  be  given  the  porcelain  in  the  step.  In  either  case 
the  lingual  plate  should  be  cut  away  more  than  the  labial,  and  this  is 
particularly  true  near  the  termination  of  the  step.  At  this  point  the 
lingual  aspect  of  the  step  should  be  made  to  dip  rootwise  quite  per- 
ceptibly to  provide  an  interlock  to  the  inlay  (Fig.  243,  lingual  view). 
Care  should  be  taken  that  there  are  no  thin  edges  left  to  the  inlay 
in  any  of  its  outline  and  this  is  accomplished  by  cutting  the  enamel 
with  little  or  no  bevel.     It  is  also  possible  in  some  instances  to  add 


276 


PREPARATION    OF    CAVITIES    FOR    INLAYS. 


to  the  bulk  of  the  porcelain  in  upper  teelh,  and  thus  increase  its 
strength  in  the  region  of  the  step,  by  building  it  fuller  lingually  than 
the  tooth  originally  was.  The  relation  of  the  lower  incisors  will 
often  admit  of  this  and  in  some  instances  it  is  advisable  to  slightly 
shorten  the  lower  tooth  to  give  the  needed  space. 

In  the  gingival  region  provision  should  be  made  for  a  broad  seat- 
ing of  the  inlay.  The  gingival  wall  should  be  flat  and  as  wide  mesio- 
distally  and  long  labio-lingually  as  the  available  tooth  tissue  will 
permit.  No  undercutting  is  of  course  permissible  but  the  labial 
and  lingual  walls  may  be  made  to  extend  from  the  gingival  wall  in  a 
very  nearly  parallel  direction.  This  will  give  a  box-like  form  to  the 
cavity  in  this  region  and  result  in  security  to  the  inlay  when  cemented. 

Cavities  for  the  restoration  0}  incisal  tips.  It  is  sometimes  found 
practical  where  the  incisal  portion  of  an  anterior  tooth  has  been 
marred  by  faulty  development,  so  as  to  be  dwarfed  and  unsightly,  to 
restore  the  end  with  porcelain.     It  is  also  possible  in  some  instances 


Fig.  244. 


Fig.  245.  Fig.  246. 


Fig.  247. 


Fig.  248. 


to  do  this  where  the  incisal  portion  of  an  incisor  has  been  broken  off 
by  a  blow,  though  the  cavity  preparation  for  the  two  is  entirely  differ- 
ent. In  the  first  instance  there  is  usually  a  thin  projection  of  tooth 
tissue  standing  on  the  end  of  the  tooth  as  if  the  enamel  had  been 
stripped  from  it,  and  this  may  be  utilized  as  a  tenon  over  which  the 
inlay  may  be  mortised  (Fig.  244,  longitudinal  section  of  an  incisor  mesio- 
distally,  Fig.  245,  longitudinal  section  labio-lingually).  The  shoulder 
where  the  perfect  enamel  begins  and  against  which  the  inlay  is  fitted 
should  be  cut  at  right  angles  to  the  tenon,  and  the  latter  so  trimmed 
that  the  matrix  may  be  fitted  over  it  and  removed  without  dragging. 

In  the  case  of  a  fractured  tooth  leaving  the  end  flat  the  problem 
of  anchorage  is  greatly  complicated.  Retention  must  be  gained  by 
drilling  into  the  fractured  surface  and  the  danger  of  approaching  the 
pulp  is  always  a  factor  in  the  case.  If  the  fracture  has  not  occurred 
far  rootwise  a  groove  may  be  made  running  mesio-distally  across  the 
tooth  (Fig.  246),  shallow  in  the  center  to  avoid  the  pulp  and  deeper  at 
each  extremity  where   it  passes   mesially   and   distally  of    the    pulp 


PREPARATION    OF    CAVITIES    FOR    INLAYS.  277 

(Fig.  247).  If  the  fracture  has  extended  so  near  the  pulp  as  to  reach  a 
thick  part  of  the  tooth  so  that  the  labio-lingual  width  of  the  fractured 
surface  will  permit  it,  two  grooves  may  be  made,  one  to  the  labial 
and  one  to  the  lingual  of  the  pulp,  and  these  should  join  the  labio- 
lingual  grooves  at  either  side  (Fig.  248).  All  grooves  for  this  purpose 
should  be  made  flat  at  the  base  and  as  broad  and  deep  as  the  tissue 
will  permit. 

Cavities  involving  the  proximal  and  occlusal  surfaces  of  bicuspids 
and  molars.  These  complex  cavities  are  usually  better  managed  by 
the  use  of  gold  inlays  than  porcelain  and  the  detail  of  cavity  formation 
herein  suggested  is  in  accordance  with  this  idea.  The  most  serviceable 
of  all  inlay  work  is  in  connection  with  the  large  restorations  frequently 
necessary  in  these  cases,  and  the  operator  should  study  carefully  the 
possibilities  of  inlays  in  those  positions  in  the  mouth  where  the  diffi- 
culty of  inserting  large  fillings  of  foil  has  frequently  proved  a  serious 
physical  and  nervous  tax  on  patient  and  operator. 

As  has  already  been  intimated  the  preparation  of  these  cavities 
involves  a  wide  extension  bucco-lingually  of  the  proximal  portion  of 
the  cavity  as  it  reaches  the  occlusal,  and  wherever  a  step  can  be  made 
in  the  occlusal  surface  at  right  angles  to  the  proximal  the  chief  reliance 
for  anchorage  should  be  in  this  step.  This  is  particularly  true  of 
bicuspids  where  the  bulk  of  tissue  for  anchorage  in  the  proximal 
region  is  not  so  great  as  in  molars.  The  step  should  be  given  a  dove- 
tailed or  interlocking  form  so  as  to  avoid  any  possible  tipping  of  the 
inlay  and  this  may  usually  be  accomplished  in  one  of  two  ways,  depend- 
ent upon  the  form  of  the  tooth.  Where  the  cusps  are  prominent 
and  the  depressions  between  them  deep  it  will  usually  be  found  that 
there  is  an  appreciable  concavity  at  the  termination  of  the  step  most 
remote  from  the  proximal  cavity,  and  in  this  instance  the  step  at  this 
point  may  conveniently  be  made  much  wider  bucco-lingually  than  it 
■  is  midway  between  the  cusps.  The  effect  is  to  dovetail  the  step  portion 
of  the  inlay  against  any  possibility  of  tipping  (Fig.  249).  Where  the 
occlusal  surface  is  more  nearly  flat  with  little  prominence  of  the  cusps 
and  almost  no  depression  between  them,  the  interlock  may  be  secured 
by  deepening  the  termination  of  the  step  rootwise  as  shown  in  Fig.  250, 
a  mesio-distal,  longitudinal  section  of  an  upper  bicuspid. 

The  same  provision  for  a  flat  gingival  wall  in  the  proximal  portion 
should  be  made  as  in  incisors,  and  the  buccal  and  lingual  walls  should 
extend  from  the  gingival  in  nearly  a  box-like  form.  If  the  cavity  is 
prepared  in  this  way  and  the  inlay  properly  fitted  it  will  snap  into 
place  whh  a  frictional  retention  against  the  walls  which  adds  greatly 


278  PREPARATION    OF    CAVITIES    FOR    INLAYS. 

to  the  sense  of  security.  Such  an  inlay  will  not  rock  or  tip  on  pressure 
even  before  it  has  been  cemented. 

In  case  the  enamel  on  the  occlusal  surface  leading  from  the  cavity 
is  perfect  and  it  is  deemed  not  advisable  to  cut  into  it  to  form  a  step, 
retention  against  tipping  may  be  secured  by  making  the  cavity  slightly 
wider  bucco-lingually  at  the  axial  wall  than  it  is  at  the  dento-enamel 
junction  (Fig.  251,  cross-section  of  a  lower  molar).  This  forms  a  dove- 
tail and  in  cases  where  there  is  sufficient  bulk  of  tooth  tissue  to  work 
on  it  may  be  done  without  weakening  the  walls.  It  is  of  course 
apparent  that  the  only  direction  in  which  a  model  or  inlay  can  be 
removed  from  such  a  cavity  is  toward  the  occlusal  surface. 

In  other  cases  where  the  dentin  is  so  involved  in  the  occlusal  region 
as  to  leave  the  axial  wall  greatly  concave  and  no  foundation  for  a  step, 
an  interlock  may  be  gained  by  shortening  one  of  the  cusps  and  build- 
ing the  inlay  over  it  (Fig.  252,  lingual  surface  of  a  bicuspid).  It  will 
be  found  in  these  cases  that  the  dentin  is  quite  extensively  dissolved 


Fig.  249.  Fig.  250.  Fig.  251.  Fig.  252. 

from  under  the  enamel  as  it  arches  over  the  cusp  and  the  wall  is  made 
more  secure  by  cutting  down  the  cusp  and  protecting  it  with  gold. 
This  may  be  done  with  both  cusps  if  necessary  where  there  has  been 
much  undermining  of  the  enamel,  and  even  this  extensive  restoration 
may  frequently  be  necessary  without  the  pulp  being  involved.  These 
are  the  cases  which  heretofore  have  been  quite  generally  consigned 
to  crowning,  but  an  inlay  restoration  such  as  just  indicated  where" 
even  the  entire  occlusal  surface  is  reproduced  in  gold  is  in  every 
respect  preferable  to  a  crown.  And  this  is  not  only  true  of  these  cases 
but  of  others  still  more  extensive  where  the  mesial,  occlusal,  and  distal 
surfaces  are  involved  in  the  same  tooth,  requiring  a  restoration  of  all 
three  with  the  gold  overlapping  the  buccal  and  lingual  walls.  (Fig.  253, 
lower  molar,  buccal  surface.) 

The  general  form  of  the  cavity  in  such  cases  must  of  course  be 
governed  by  the  conditions  presented.  Weak  or  overhanging  enamel 
should  be  ground  away  quite  freely  for  the  double  purpose  of  securing 
a  firm  foundation  and  for  thoroughly  opening  up  the  cavity.     The 


PREPARATION    OF    CAVITIES    FOR    INLAYS.  279 

principle  of  the  flat  seat  for  the  inlay  to  rest  upon  should  be  maintained 
as  largely  as  possible,  because  of  the  necessity  for  security  against 
dislodgment  under  the  severe  stress  of  mastication  to  which  such 
restorations  are  subjected.  The  enamel  margins  should  be  beveled 
away  quite  freely  with  the  utmost  confidence  that  the  gold  will  form  an 
adequate  protection  to  them.  _.^        ,.-^, 

In  case  the  pulp  is  dead  advantage  may  be  taken  of    /   ^^'^^^--^  \ 
the  pulp  chamber  for  anchorage  after  the  canals  have 
been  filled,  but  in  the  event  of  this  additional  anchor- 
age not  being  required  the  chamber  may  be  filled  with  „ 
cement  and  this  leveled  to  form  a  flat  seat  for  the  inlay.      '      ^/^     '°^' 

Cavities  in  the  occlusal  surfaces  of  bicuspids  and  ^^°'  *53- 
molars.  It  is  a  very  rare  condition  which  calls  for  an  inlay  in  the 
occlusal  surface  of  a  bicuspid  unless  it  involves  some  other  surface. 
A  simple  occlusal  cavity  can  be  more  judiciously  managed  with  a 
filling  than  an  inlay,  and  it  is  only  in  molars  with  cavities  of  appre- 
ciable extent  where  it  is  judicious  to  make  occlusal 
inlays.  The  preparation  of  these  cavities  is  not  com- 
plicated. The  floor  or  pulpal  wall  should  be  made  flat 
so  as  to  be  at  right  angles  to  the  stress  of  mastication, 
and  the  surrounding  walls  should  be  nearly  parallel  to 
make  a  mortised  effect  to  the  inlay  (Fig.  254,  section 
of  a  lower  molar). 
In  cases  where  there  has  been  an  extensive  involvement  of  the 
tissue  undermining  the  occlusal  enamel  leaving  it  frail,  it  may  be 
ground  down  slightly  past  the  marginal  ridge  and  the  entire  occlusal 
surfiace  reproduced  in  gold  (Fig.  255). 

The  technique  of  cavity  preparation  for  inlays  is 
quite  simple  and  the  operation  altogether  more  accept- 
able to  the  patient  than  for  fillings.  There  is  no 
necessity  for  applying  the  rubber  dam  and  this  to  many 
is  a  great  relief.  The  cutting  is  mostly  done  with 
chisels,  excavators,  and  such  rotary  appliances  as 
stones,  wheels  and  disks.  The  only  necessity  for  the 
use  of  burs  in  large  cavities  is  in  sharpening  up  some  of  the  line 
angles,  and  to  flatten  the  walls  left  rounding  by  the  stones.  The 
fact  that  the  grinding  may  be  done  under  moisture  reduces  the 
pain  to  the  minimum,  and  this  is  a  great  recommendation  for  this 
class  of  work. 


CHAPTER  XVI. 
THE  PORCELAIN  INLAY. 

BY  W.  A.  CAPON,  D.D.S. 

The  eventual  success  of  porcelain  as  a  filling  for  teeth  depends 
upon  thorough  consideration  of  two  primary  principles,  viz.,  founda- 
tion and  adaptation.  The  first  term  applies  to  cavity  preparation, 
the  second  to  matrix  formation,  and  they  are  closely  allied  in  im- 
portance. The  consideration  of  the  former  by  a  preceding  chapter 
allows  the  matrix  to  become  my  first  topic. 

METHODS 

There  are  two  methods  of  making  a  matrix  called  the  "direct"  and 
"indirect"  and  either  can  be  used  according  to  the  desire  and  training 
of  the  operator.  The  indirect  method  consists  of  taking  an  impression 
of  the  cavity  with  modeling  compound  or  a  hard  wax  and  making  a 
model  of  some  hard  material  such  as  amalgam,  cement  or  low-fusing 
metal. 

There  are  many  adherents  of  this  mode  of  making  an  inlay  who  claim 
equal  results  with  the  older  and  more  popular  method  of  working  di- 
rectly on  the  natural  tooth.  It  is  a  debatable  point  which  is  best  settled 
by  thorough  trial  by  the  student.  The  advantage  claimed  is  that  in- 
la,yr  are  made  by  assistants  and  a  series  of  operations  carried  at  the  same 
time  without  delay.  In  the  writer's  estimation  there  are  disadvantages 
that  more  than  offset  what  is  claimed,  viz: 

A  greater  cutting  of  tooth  substance  to  allow  an  impression  material 
to  accurately  portray  the  cavity  edges. 

The  difficulty  of  reproducing  with  any  material  a  cavity  edge  as  per- 
fect as  the  natural  tooth  enamel.  The  amount  of  technique  required 
before  a  matrix  can  be  made,  and  finally  the  passing  to  a  subordinate 
the  astistic  and  most  important  part  of  the  operation.  However,  that 
may  be  a  motive  for  many  who  enthusiastically  claim  the  indirect 
method  as  being  preferable. 

The  writer's  many  years'  experience  has  proven  the  direct  method  of 
taking  the  matrix  to  be  simpler  and  more  expeditious  and  therefore 
presents  that  procedure  in  detail  as  follows: 

281 


282 


THE    PORCELAIN    INLAY. 


The  metals  used  for  matrices  in  porcelain  inlay  work  are 
made  of  either  platinum  or  gold  foil  and  their  respective 
value   for  this  purpose  is  usually  an  argumentative  point 
whenever  the  subject  of  high  or  low  fusing  porcelain  is  dis- 
cussed.    Adherents  of  high  fusing  porcelain  have  no  choice 
except  platinum  while  the  advocates  of  lower  heat  material 
can  use  either  gold  or  platinum.     Platinum  has  for  its  recom- 
mendation adaptability  and  stability  of  form,  together  with 
its  great  resistance  to  high  heat,  thus  dispensing  with  the 
necessity  for  an  investing  material  to  keep  its  form.     The  vir- 
tue of  gold  is  its  ductihty  and  easy  adaptability  to  floor  and 
walls  of  cavity,  but  this  very  softness  in  the  majority  of  cases 
renders  an  investment  necessary,  thus  precluding  any  trial 
fitting  or  reburnishing  which  is  of  so  much  assistance  espe- 
cially to  the  beginner.     It  being  my  intention  to  describe 
the   use  of   high  fusing  porcelain  particularly,  I  have  no 
alternative  of  a  choice  of  metals  for  a  matrix  even  if  so  de- 
sired, and  will  consider  the  subject  from  this  point  of  view. 
The   difficulties  connected  with  making  a  matrix  are 
^      somewhat  regulated  by  the  position  of  the  cavity  and  the 
amount    of  working  space  in  its  immediate  vicinity,  therefore 
it  may  simplify  the  subjects  to  divide  them  into  three  grades  as      , 
follows:  V. 

T.  Labial  and  buccal  cavities. 

2.  Proximal  cavities  in  anterior  teeth  with  lingual  surface  not  in- 
volved.    Gingival  cavities  curving  well  to  the  proximal. 

3.  Proximal   cavities  in  incisors  involving  lingual  surface,  prox- 


METHODS. 


283 


Fig.  257. 


imo-incisal  restorations,  distal  surface  of  cuspids,  mesial  surface  of 
first  and  second  bicuspid  and  first  molar. 

Sufficient  space  between  teeth  is  imperative  with  this  class  of 
operations  because  porcelain  is 
unyielding  and  cannot  be  forced 
to  position  without  risk  of  chip- 
ping  edges.     The  matrix  must 
come   from   the   cavity  without 
change  of  form  and  frequently 
there  is  plenty  of  space  for  the 
inlay  when  finished,  but  owing 
to  necessary  excess  of  matrix  ma- 
terial it  locks  itself  when  there  is  apparently  sufficient  space. 
The  impression    of  the  cavity  or  matrix  is  made  with  gold  foil 
No.  40  or  pure  platinum  gauge  i/iooo  in.  or  .001  in.  thick- 
ness— thoroughly  annealed.  ■  In  these  days  of  inlay  requisites 
this  material  is  kept  ready  for  use  by  all  dental  dealers,  but  it 
should   not  be  handled  much  before  using  and  it  should  be 
pure.     If  greater  softness  is  required  give  it  a  high  heat  in  the   ||| 
furnace  muffie.     I  emphasize  the  word  pure  because  iridium   |||| 
and  platinum  are  naturally  alloyed  and  as  iridium  is  the  most    ||| 
difficult  metal  of  the  platinum  group  to  eliminate,  this  fact  may    ||| 
account  for  the  variance  in  softness  in  different  purchases.     The 
proper  thickness  of  the  metal  has  been  a  point  of  considerable 
discussion,  but   it  is  now  generally  conceded  that  i/iooo  is 
the  correct  thickness  for  most  operations.     It  may  sometimes  be    |l|i 
slightly  heavier,  but  never  thinner.     Many  argue  that  if  i/iooo 
is  good  1/2000  must  be  better  because  of  the  minimum  amount 
of  metal  at  the  edges,  forgetting  or  not  knowing  that  burnishing 
reduces  thickness  to  a  lighter  gauge. 

Labial  cavities  in  central  incisors  are  in  the  first  grade,  there- 
fore a  detailed  description  will  be  more  easily  understood. 

The  foil  is  cut  sufficiently  large  to  allow  holding  against  ad- 
joining teeth,  and  somewhat  diamond  shaped,  the  extreme  ends 
being  held  firmly  by  the  first  and  second  fingers  of  the  left  hand, 
leaving  the  right  hand  free  to  use  the  instruments  for  burnishing. 

My  preference  is  for  few  and  simple  instruments  such  as    HMI 
two  or  three  sizes  of  rubber  tips  and  some  amalgam  burnishers. 

Special  instruments  such  as  those  designed  by  Dr.  W.  T.  Reeves, 
and  Dr.  C.  N.  Thompson  have  extensive  use  and  fulfill  the  require- 
ments desired.      (Figs.  256  and  257.)     Dr.  Jenkins  presents  new  bur- 


284  THE    PORCELAIN    INLAY 

nishers  made  of  glass.  It  is  claimed  that  the  metal  is  forced  to  position 
with  less  danger  of  tearing  because  of  the  absolute  smoothness  of 
contact  surface. 

Whenever  possible  it  is  well  to  give  the  outline  of  the  cavity  by  the 
rubber  points  or  spunk  held  by  ball  tipped  pliers  pressed  firmly  over 
the  cavity,  stretching  the  metal  with  safety,  then  rotating  a  ball 
pointed  instrument  with  gentle  pressure,  commencing  with  a  large 
size,  following  with  smaller  ones  until  the  metal  is  fairly  well  adjusted; 
then  use  small  pieces  of  spunk,  chamois  skin  or  camphor,  packing 
tightly.  It  is  now  safe  to  use  the  other  hand  and  with  it  hold  the 
matrix  in  place  with  a  blunt  instrument  pressing  the  packing,  then 
burnish  edges  thoroughly,  but  not  roughly  for  fear  of  tearing.  A 
break  on  the  cavity  edge  means  a  new  mold  while  one  at  the  bottom 
of  the  matrix  is  of  no  moment.  Remove  spunk  or  whatever  has  been 
used  as  an  assistant  and  carefully  release  the  matrix  which  is  now 
ready  for  the  porcelain.  If  inadvertently  there  is  an  undercut  in 
the  cavity  sufficient  to  lock  the  matrix,  gently  force  it  out,  then  re- 
place and  reburnish  the  edges,  not  touching  the  interior,  thereby 
making  a  change  of  the  cavity  unnecessary. 

The  making  of  a  matrix  for  a  proximal  cavity  requires  more  skill 
and  practice.  The  foil  should  be  carried  well  above  the  gingival 
margin  of  the  cavity  and  if  the  gum  is  even  with  it  the  edge  of  the 
metal  should  be  turned  to  look  tow^ard  the  proximating  tooth  and 
lie  over  the  gum,  giving  a  sure  working  surplus.  Rubber  points  are 
not  much  used  in  these  places,  therefore  take  the  flat  end  of  a  bur- 
nisher and  press  across  the  cavity  edges  gently,  forcing  the  foil  to  posi- 
tion assisted  by  small  squares  of  spunk.  The  burnishing  and  general 
procedure  is  the  same  as  for  a  simpler  cavity  except  that  usually  surplus 
foil  is  in  the  way  if  both  labial  and  lingual  surfaces  are  burnished  flat  to 
the  tooth,  therefore  if  drawing  from  the  labial  side,  have  the  lingual 
surface  approximately  burnished,  take  out  and  cut  surplus  off,  then 
replace  and  get  outline  more  perfectly  and  thus  save  a  probable 
twisting  of  the  matrix  caused  by  an  excess  of  material.  If  the  cavity 
has  greater  presentation  toward  lingual  surface  the  same  rule  is 
applied.  Many  practitioners  suggest  that  much  assistance  can  be 
gained  by  holding  matrix  in  place  with  rubber  dam,  gold  beater's 
skin,  or  china  silk,  and  burnishing  the  matrix  through  these  materials. 

Some  years  ago  Dr.  Allen,  of  Kansas  City,  added  gum-cam- 
phor to  our  equipment  as  an  assistant  in  making  a  matrix  and  it 
is  most  excellent  when  used  properly,  but  many  operators  make 
the  mistake  of  using  it  everywhere,  forcing  it  in  the  cavity  when  the 


METHODS.  285 

matrix  is  unprepared,  and  the  result  is  an  aperture  from  edge  to  edge 
therefore  it  is  well  to  have  the  cavity  walls  fairly  outlined  before  using 
it.  It  is  of  most  value  in  labial  cavities  or  where  there  is  plenty  of  space 
to  permit  of  easy  withdrawal.  After  the  matrix  is  made  it  is  recom- 
mended that  it  be  thoroughly  cleansed  by  placing  it  in  alcohol  which  will 
cleanse  it  of  saliva  or  blood  if  camphor  packed.  The  action  of  alcohol 
will  dissolve  the  mass  so  it  will  drop  out.  Passing  it  through  an  alcohol 
flame  will  burn  it  out  leaving  no  residue  which  is  one  of  the  recommen- 
dations for  using  this  material  for  packing;  however,  if  gold  is  being  used 
it  is  safer  to  use  alcohol  alone.  After  the  matrix  is  cleansed  clasp  the 
surplus  portion  firmly  with  a  pair  of  straight  fine  pointed  tweezers  and 
fill  the  mold  with  the  shade  of  porcelain  chosen,  which  is  mixed  with 
clean  water  or  alcohol  or  a  mixture  of  both  and  applied  with  a  fine 
pointed  sable  pencil  brush  and  the  little  lump  of  stifif  porcelain  is 
gently  patted  or  jarred  to  place.  The  edges  of  the  cavity  form 
are  traced  clean  with  point  of  brush  and  the  embryo  inlay  is  laid  face 
down  on  absorbent  paper  or  a  clean  napkin  which  abstracts  the  surplus 
moisture.  Dusting  dry  porcelain  over  the  moist  surface  is  also  recom- 
mended. I  prefer  applying  the  first  piece  so  dry  that  it  is  difficult 
to  pick  up  with  the  brush.  It  is  at  this  point  that  the  advantage  of 
a  sable  brush  is  noticed  because  it  holds  a  point  without  drooping 
while  camel's  hair  droops  and  has  no  stability. 

If  the  matrix  should  have  a  pierced  or  broken  bottom  which  is 
almost  unavoidable  in  a  deep  cavity,  fill  it  as  if  it  were  intact  and 
unless  the  aperture  is  extremely  large  it  is  surprising  how  much  tap- 
ping or  forcing  is  required  to  make  the  porcelain  pass  through ;  however 
under  all  circumstances  it  is  a  safe  rule  to  turn  the  matrix  bottom 
side  up  and  examine  it  closely  and  trace  it  with  a  clean  brush,  other- 
wise a  very  small  particle  of  porcelain  left  unnoticed  and  becoming 
fused  will  make  the  work  to  this  point  useless. 

If  a  break  is  made  on  the  cavity  edge  of  the  matrix,  condemn 
it  and  make  another,  as  it  is  impossible  to  have  a  perfect  margin  unless 
the  matrix  is  intact  on  that  margin. 

When  excess  of  moisture  has  been  removed,  place  it  on  a  metal 
or  fire  clay  tray  at  the  mouth  of  the  furnace,  gradually  pushing  it  to 
the  interior,  using  care  that  too  quick  evaporation  does  not  loosen 
porcelain  from  walls  of  the  matrix.  If  this  occurs  a  refilling  of  the 
mold  is  the  only  alternative.  Close  the  door  of  furnace  and  the 
process  of  fusing  has  commenced.  The  shrinkage  of  porcelain  plays 
a  prominent  part  in  all  such  operations  and  unfortunately  it  keeps 
the   most   experienced   "guessing,"   therefore  those   unfamiliar  with 


286  THE    PORCELAIN    INLAY. 

the  work  are  handicapped  at  the  beginning  by  a  difficulty  that  mut- 
be  reckoned  with  always.  In  fact  a  student's  first  lesson  is  the  shows 
ing  of  an  artificial  tooth  before  fusing  and  after,  and  it  never  fails  to 
create  surprise  and  comment  and  is  a  simple  object  lesson  that  im- 
presses. Shrinkage  of  porcelain  is-  always  a  fifth  of  its  bulk,  some- 
times quite  one-fourth.  In  small  matrices  it  cannot  make  much 
change,  but  in  proportion  to  the  size  and  quantity  do  the  diffi- 
culties increase.  It  may  draw  from  the  walls  of  the  matrix  and  form 
crevices  at  those  parts,  or  it  may  shrink  and  draw  the  form  with  it, 
and  to  avoid  this  my  favorite  way  is  to  mix  small  particles  of  broken 
porcelain  with  the  paste.  Another  way  is  to  cut  grooves  or  concaves 
at  its  greatest  bulk  which  divides  the  material  and  avoids  the  crevicing 
to  some  extent.  The  main  desire  is  to  have  a  shrinkage  that  will 
change  the  form  of  the  matrix  the  least,  and  some  porcelains  have  a 
value  in  this  respect.  An  invested  matrix  is  more  secure,  but  it  has 
drawbacks  that  in  my  estimation  are  often  detrimental.  A  matrix 
for  investment  must  be  intact  at  every  point  which  is  possible  with 
gold,  but  not  always  so  with  platinum.  Once  invested  it  must  be 
completed  in  that  form  thus  debarring  opportunities  for  trial  or  re- 
burnish,  added  to  which  are  the  increased  difficulties  of  getting  proper 
form  or  contour  while  invested. 

FUSING. 

This  is  the  coherence  into  a  solid  mass  of  the  various  substances 
which  constitute  porcelain  and  it  is  this  cohesiveness  which  causes 
shrinkage,  and  because  of  this  shrinkage  repeated  firing  is  imperative 
to  obtain  the  necessary  bulk  of  iolidified  material.  It  may  be  twice, 
three  times  or  more  according  to  the  extensiveness  of  the  operation, 
therefore  a  knowledge  of  fusing  is  an  important  part  of  making  an 
inlay,  and  one  that  necessitates  considerable  experience.  Of  course 
results  are  obtained  without  experience  or  much  practice,  but  these 
results  are  not  always  properly  fused  porcelain.  To  illustrate  this 
point  let  me  state  that  a  certain  dealer  and  manufacturer  wishing  to 
impress  upon  the  profession  the  advantages  of  a  pyrometer  attachment 
molded  small  pellets  of  porcelain  of  equal  size  and  of  one  color  and 
mailed  them  to  "porcelain  workers"  in  various  parts  of  the  country, 
asking  them  to  fuse  and  return.  I  was  so  favored  with  this  request, 
but  did  not  know  the  results  for  some  months  afterwards  when  by 
chance  I  saw  the  "returns"  mounted  on  a  card  for  exhibition  pur- 
poses and  the  various  shades  and  qualities  produced  by  that  one  little 
pellet  was  a  revelation.     They  were  all  supposed  to  be  correctly  fired 


FUSING.  287 

and  no  doubt  each  participant  in  this  trial  thought  his  specimen  a 
correct  one.  This  shows  in  a  simple  manner  why  there  is  so  much 
demand  for  information  regarding  shading,  which  demand  can  be 
lessened  by  greater  knowledge  of  fusing.  How  can  this  knowledge 
be  obtained  in  the  most  practical  manner?  By  studying  the  various 
degrees  of  heat  with  the  eye  which  may  be  aided  by  a  watch  or  a 
pyrometer,  but  with  either  of  these  or  any  other  guide  the  correct 
fusing  or  baking  of  porcelain  reduces  the  problem  to  one  of  per- 
sonal equation. 

A  pellet  of  gold  is  recommended  by  many  to  assist  in  determining 
the  fusing  points.  The  gold  is  placed  in  the  muffle  near  the  inlay 
and  its  melting  denotes  the  fact  that  a  certain  temperature  is  reached, 
and  so  much  time  by  the  watch  is  allowed  between  the  melting  of  the 
gold  until  the  fusing  of  the  porcelain.  The  time  to  allow  is  learned 
by  repeated  firings,  but  various  sizes  of  porcelain  being  baked  at  the 
same  time  must  be  guessed  at. 

The  use  of  a  pyrometer  in  connection  with  a  furnace  is  accepted 
by  many  as  being  the  most  scientific  solution  of  our  fusing  troubles, 
and  there  is  no  doubt  that  it  is  of  much  assistance  to  the  majority, 
but  it  is  a  machine  and  therefore  it  has  no  judgment  and  fusing 
porcelain  requires  that  necessity.  Concentration  of  a  thousand  heat 
units  for  twenty  minutes  will  produce  certain  results  and  the  same 
condition  will  be  obtained  by  increasing  the  volume  and  reducing  the 
time,  and  as  we  are  fusing  irregular  quantities,  either  the  heat  or 
fusing  point  must  be  varied  because  these  fusing  points  now  used  as 
a  standard  were  obtained  by  baking  porcelain  pellets  of  uniform  size 
at  a  regular  heat  for  a  certain  time  with  the  rheostat  on  a  positive 
point.  These  facts,  therefore,  must  place  the  pyrometer  in  the  position 
it  should  occupy  and  that  it  is  a  guide  which  will  indicate  the  furnace 
heat  and  not  properly  tell  when  the  fusing  has  taken  place.  The  man 
who  uses  his  eye  as  a  guide  can  fuse  any  material  under  all  circum- 
stances and  feel  that  he  has  control  of  the  situation,  providing  he  uses 
an  article  which  fuses  at  2300°  or  less.  Over  that  point  it  is  a  greater 
strain  on  the  eyes  and  the  value  of  a  pyrometer  is  correspondingly 
increased,  but  the  proportion  of  operators  using  such  excessive  heat 
for  inlays  is  very  small. 

The  operator  after  some  practice  will  observe  that  various  degrees 
of  heat  have  a  shade  indicative  of  the  point  he  desires.  The  first 
will  be  a  deep  orange  color  which  will  fuse  a  low  porcelain  body  ranging 
from  1500°  F.  to  1800°  F.  If  an  electric  furnace  is  being  used,  ad- 
vancing the  rheostat  to  the  next  point  will  increase  the  brightness  of 


288  THE    PORCELAIN    INLAY. 

the  muflle  to  a  yellow,  giving  a  fusing  temperature  ranging  to  2100°, 
and  another  step  higher  a  bright  yellow  appearance,  and  a  heat 
sufficient  to  fuse  most  of  the  "high  fusing"  bodies  or  those  ranging 
in  the  neighborhood  of  2300°.  Beyond  this  point  there  is  a  glare 
that  may  be  injurious  to  the  eyes  unless  protected  by  smoked  glasses. 

Dr.  Hart  J.  Goslee,  in  a  recent  article  on  this  subject  makes  a 
valuable  suggestion  that  I  take  the  liberty  of  quoting.  "A  degree  of 
familiarity  with  the  physical  change  which  takes  place  during  vitrifi- 
cation and  which  will  enable  one  to  thus  detect  the  proper  fusion, 
may  be  easily  required  by  the  continued  fusing  of  small  cubes  of 
properly  mixed  'body'  placed  upon  the  labial  surface  of  a  central 
incisor  facing  until  he  can  distinguish  between  the  granular  surface 
of  the  '  body '  and  the  glazed  surface  of  the  facing  and  observe  when 
the  surface  of  the  former  becomes  the  same  as  that  of  the  latter." 

The  "first  fusing"  is  carrying  the  inlay  through  these  various 
stages  of  heat  until  it  arrives  at  what  is  usually  termed  a  "biscuit 
bake."  This  is  a  reduction  of  the  different  ingredients  to  a  solid 
vitrified  mass  without  a  gloss.  Drawing  it  from  the  furnace  in  this 
condition  and  exposing  it  to  the  air  does  it  no  injury,  in  fact  small 
work  even  when  finished  does  not  require  particular  care  in  this 
respect,  but  large  sections  and  crowns  should  be  immediately  placed 
in  a  cooling  muffle  until  cool  enough  to  handle. 

After  the  first  bake  the  surplus  platinum  is  trimmed  and  the  inlay 
adjusted  in  the  cavity.  The  removal  of  excess  matrix  material  insures 
easier  access  to  its  position  and  allows  a  better  observance  of  general 
contour.  The  fiat  blade  of  a  burnisher  is  pressed  along  the  edges 
until  the  matrix  sets  firmly  in  position  and  that  part  of  the  matrix 
which  may  have  been  changed  by  the  shrinkage  is  forced  back  to  the 
cavity  walls.  The  inlay  is  again  removed  and  body  added,  first 
cleaning  off  the  surface  with  a  brush,  being  careful  to  have  any  crevice 
thoroughly  filled  with  porcelain,  thereby  preventing  little  air  holes 
which  sometimes  defy  considerable  tapping.  Reburnishing  the  inlay 
will  soil  the  surface  to  some  extent  and  it  may  also  come  in  contact  with 
saliva  or  blood,  therefore  dip  it  in  alcohol,  and  place  at  mouth  of  fur- 
nace until  the  impurities  are  destroyed  by  heat,  thus  insuring  a  positively 
clean  surface  and  unalloyed  porcelain.  The  inlay  is  again  given 
the  same  considerations  as  at  first  baking,  but  watched  with  greater 
care  when  the  heat  is  nearing  the  fusing  point,  because  insufficiency 
of  heat  will  not  produce  the  true  shade  or  finished  surface,  while 
too  much  heat  will  make  it  lighter  in  proportion  to  the  excessive  heat 
beyond  the  exact  point,  and  reduce  the  quality  of  the  material. 


FUSING.  289 

Better  results  will  be  obtained  by  withdrawing  the  inlay  before 
it  is  thoroughly  fused  and  note  the  condition  particularly  in  regard 
to  amount  of  material,  for  if  another  layer  of  porcelain  is  required 
to  give  it  the  proper  contour  or  to  have  the  inlay  level  with  the  margins 
of  the  matrix,  it  is  better  to  make  this  addition  at  this  time,  and  in  so 
doing  the  whole  mass  will  be  more  homogeneous  with  a  truer  shade 
if  the  final  heat  is  correctly  gauged. 

If  the  inlay  is  satisfactory  to  the  operator  the  next  step  is  to  strip 
the  matrix,  which  is  done  with  fine  straight  pointed  tweezers,  catching 
the  outer  edge  and  turning  backwards  toward  the  middle  which  will 
avoid  chipping  the  edges.  Very  frequently  small  pieces  of  the  metal 
adhere  very  persistently  to  sections  of  the  porcelain.  These  may  not 
be  of  disadvantage  in  large  inlays,  but  in  small  ones  the  shade  might 
be  affected,  therefore  it  is  recommended  that  every  portion  be  removed, 
and  an  old  bur  will  do  this  easily.  My  usual  procedure  after  stripping 
the  matrix  is  to  place  the  inlay  in  the  cavity,  always  wet,  which  brings 
out  the  shade  and  adds  life  to  it,  and  it  is  at  this  point  the  new  porcelain 
worker  has  his  first  desire  for  a  transparent  cement.  It  is  now  that 
the  patient  is  invited  to  view  it  for  he  is  usually  as  interested  as  the 
dentist,  and  it  is  also  good  policy  to  explain  the  probable  change  that 
will  take  place  by  the  drying  of  the  tooth  and  the  cementation.  This 
change  is  often  temporary  though  sometimes  permanent,  much  to 
our  disappointment,  but  experience  may  help  to  reduce  it  to  the 
minimum. 

The  inlay  must  now  be  prepared  for  retention.  There  are  three 
important  factors  toward  permanency,  first,  shape,  which  is  given 
by  due  consideration  of  cavity  preparation,  second,  the  undercutting 
or  serration  of  the  porcelain,  and  third,  the  quality  of  cement.  Many 
failures  can  be  attributed  to  concentration  on  the  latter,  ignoring  the 
importance  of  the  first  two  requisites.  Careful  attention  should  be 
given  to  the  inlay  itself,  large  or  small,  thereby  saving  time,  discomfort 
and  reputation.  My  preference  is  undercutting  or  grooving  when 
possible,  but  that  is  not  always  practicable,  so  it  may  be  necessary  to 
etch  the  cavity  side  of  the  inlay  with  hydrofluoric  acid  which  has  a 
powerful  chemical  affinity  for  all  vitrified  surfaces,  destroying  the 
gloss  and  allowing  a  better  union  with  the  cement.  Almost  the  same 
results  are  obtained  by  using  small  carborundum  or  corundum 
stones,  and  many  follow  this  method  exclusively,  while  others  use  both 
roughening  and  grooving. 

The  disks  employed  are  diamond,  hard  rubber  and  corundum  or 
carborundum.  The  diamond  disks  are  expensive  and  unless  used 
19 


290  THE    PORCELAIN    INLAY. 

carefully  very  soon  lose  their  efficiency.  The  cheaper  disks  cut 
quickly  and  with  moderate  care  are  durable.  An  objection  to  car- 
borundum is  its  brittleness,  and  the  fine  black  dust  that  lodges  in  the 
porcelain  and  is  not  always  easy  to  eradicate.  The  groove  should 
be  made  on  at  least  two  sides  and  more  if  possible.  In  using  acid 
care  must  be  taken  to  keep  the  finished  surface  intact  and  this  is  done 
by  making  a  block  of  beeswax  about  one  inch  square,  soften  a  surface 
over  a  flame  and  sink  the  inlay  face  down  using  a  warm  spatula  to 
cover  edges.  Drop  a  little  acid  on  the  exposed  surface  and  leave  it 
for  five  to  eight  minutes,  wash  off  with  water  and  put  the  inlay  in 
alcohol  which  will  loosen  a  fine  scale  which  is  scraped  off  with  an 
excavator.  If  this  surface  is  not  removed  the  cement  will  not  get 
a  true  attachment.  No  matter  how  the  inlay  is  prepared  it  should 
be  thoroughly  cleaned  with  alcohol.  The  mouth  is  now  put  in  readi- 
ness for  the  final  adjustment  of  the  inlay.  Thorough  dryness  is  an 
important  essential,  and  for  this  purpose  probably  the  rubber  dam  is 
the  most  efficacious,  although  if  one  is  accustomed  to  the  proper  use  of 
napkins,  the  unpleasantness  of  the  dam  can  be  avoided  in  the  majority 
of  cases.  The  cement  is  mixed  to  a  creamy  consistency  and  applied 
to  the  cavity  with  a  spatula  and  the  inlay  inserted  immediately,  forcing 
it  to  position  by  gentle  pressure,  holding  it  there  until  crystallization 
has  commenced.  If  the  inlay  is  of  a  simple  character  further  direc- 
tions are  unnecessary,  but  if  complex  and  extending  to  the  incisal  or 
occlusal  surface  material  assistance  is  obtained  by  a  soft  wooden 
wedge  such  as  a  tooth  pick,  or  waxed  floss  silk  wound  about  the  tooth. 
A  tape  floss  silk  or  cotton  strip  is  advantageous  because  the  broader  sur- 
face equalizes  the  pressure  and  as  it  is  drawn  over  the  joints  it  removes 
excess  cement  and  exposes  the  union,  showing  at  a  glance  if  the  porce- 
lain has  its  correct  position.  When  it  is  not  convenient  to  do  this  use 
small  squares  of  spunk,  which  is  soft  and  firm,  for  the  removal  of  excess 
cement  while  it  is  soft  has  a  distinct  advantage. 

After  the  cement  has  set  and  before  removal  of  dam  or  napkin 
cover  the  operation  with  some  moisture  preventative  such  as  sandarac 
or  rubber  varnish,  chlora-percha  or  paraffin  wax.  The  last  men- 
tioned is  preferable  because  it  is  not  disfiguring  and  gives  a  blending 
effect  to  the  porcelain  and  tooth  and  will  remain  a  sufficient  time 
for  the  purpose  desired.  The  inlay  may  be  finished  in  an  hour  or  at 
some  future  sitting  for  there  is  always  some  finishing  with  the  most 
perfect  work.  It  may  be  only  a  slight  disking  or  it  may  be  that  edges 
need  a  stone.  If  so  use  a  small  narrow  edge  of  fine  grit,  grinding  no 
more  off  the  glossed  surface  than  positively  necessary,  although  at 


PORCELAIN    SECTION    ATTACHMENT.  29I 

times  the  occlusion  is  such  that  the  surface  must  be  defaced.  After 
grinding,  the  surface  should  be  polished,  smoothness  being  the  main 
object. 

PORCELAIN  SECTION  ATTACHMENT. 

When  it  is  possible  to  use  an  all-porcelain  anchorage  in  restoring 
a  section  of  a  tooth,  that  method  is  preferable,  because  the  whole 
mass  of  material  is  of  one  substance,  thereby  rendering  greater  resis- 
tance to  leverage;  but  occasionally  we  must  resort  to  other  means  of 
retention,  and  the  use  of  platinum  wire  pins,  loops,  or  staples  is  rec- 
ommended. 

Pins  from  old  porcelain  teeth  can  be  used  without  any  other  prepara- 
tion, but  they  are  too  thick  and  rarely  indicated  in  preference  to  the 
loop  or  staple,  the  latter  being  adapted  to  almost  every  purpose  and 
being  also  easier  to  manipulate.  Directions  for  their  use  are  few 
and  easily  followed.  The  tooth  is  prepared  as  directed  on  previous 
pages,  and  a  platinum  matrix  made  of  the  edges  and  cavity,  the  thick- 
ness the  same  as  in  other  inlay  work  excepting  for  the  cross-section 


Fig.  258.  Fig.  259.  Fig.  260. 

of  a  tooth,  when. it  can  be  slightly  heavier.  The  wire  being  the  an- 
chorage, it  is  unnecessary  to  cover  the  floor  of  the  cavity  with  platinum, 
therefore  breaking  the  matrix  is  expected.  This  being  done,  take 
iridio-platinum  wire  gauge  24  and  bend  in  staple  form  to  fit. 

Figs.  258  and  259  give  the  idea  of  wire  formation  for  a  majority  of 
cases,  while  that  shown  in  Fig.  260  is  probably  more  desirable  where 
there  is  extreme  sensitiveness,  it  being  easier  to  place  retention  holes 
for  wire  ends  than  to  cut  across  the  tooth  to  accommodate  the  loop. 
The  staple  with  points  in  the  porcelain  is  stronger,  however,  than  that 
with  the  points  in  the  tooth.  The  attachment  to  the  tooth  may  be 
equal  in  strength,  but  the  tip  or  corner  or  any  section  of  the  porcelain 
having  the  least  foreign  material  must  be  the  stronger,  hence  the 
argument  in  favor  of  an  all-porcelain  attachment  when  that  is  possible. 
The  weak  points  of  the  porcelain  shown  in  Fig.  261  are  opposite  to  the 
ends  of  the  wire,  while  the  weak  point  of  that  shown  in  Fig.  262  is  as 
far  as  the  loop  extends,  although  this  weakness  will  be  less  in  pro- 
portion to  thickness  of  the  porcelain. 

While  the  matrix  is  in  position,  the  wire  is  inserted  and  held  there 


292  THE    PORCELAIN    INLAY. 

with  paste  porcelain  made  of  water  and  gum  tragacanth  or  mixing 
fluid.  Absorb  moisture  with  bibulous  paper  or  spunk  and  then  gently 
withdraw  the  combination  from  the  tooth,  and  after  carefully  drying 
at  the  mouth  of  the  furnace  fuse  it  the  same  as  other  work. 

These  few  simple  directions  will  save  the  time  and  trouble  nec- 
essary for  soldering  the  staple  and  matrix  together,  and  will  also  insure 
a  purity  of  porcelain  not  otherwise  possible. 

Fig.  263  shows  the  loops  or  pins  attached  in  the  porcelain  and  ready 


E3^ 

Fig  261  Fig.  262  Fig.  263. 

for  trial,  reburnishing  the  edges  and  finishing  as  represented  by  Figs. 
264  to  267. 

Fig.  268  is  a  part  section  of  a  bicuspid  showing  a  way  of  restoring 
that  is  most  satisfactory.  I  have  made  many  such  cases,  and  have 
yet  to  learn  of  the  first  failure.  A  whole  crown  is  no  doubt  quite  as 
easy  to  make,  but  at  times  a  demand  for  the  least  loss  of  tooth  makes 
such  a  repair  desirable. 

The  building  of  tips  and  corners  can  be  more  quickly  accom- 
plished by  using  pieces  of  broken  porcelain  tooth  in  the  foundation, 
thus  allowing  a  high  heat  without  change  in  the  prominent  contour. 

Some  years  ago  a  firm  in  London  introduced  small  wedges  of 
porcelain   called   "Mellersh   Cores,"   their  name   being   taken   from 


Fig.  266.  Fig.  267.  Fig.  268 


that  of  the  inventor.  They  are  in  various  shades  and  will  take  a  high 
heat  without  change  of  form  or  color,  and  can  therefore  be  used  to 
advantage  in  contour  work. 

CEMENT. 

It  is  generally  conceded  by  porcelain  operators  that  while  a  material 
of  this  kind  is  almost  an  ideal  filling,  it  falls  short  of  the  ideal  because 
we  are  forced  to  use  as  an  attachment  a  substance  detrimental  to  the 
aim  which  we  have  in  view,  namely,  the  absolutely  invisible  restoration 
of  tooth  form.     Though  approximating  the  ideal  we  can  never  fully 


CEMENT.  293 

reach  it  while  we  have  to  depend  upon  an  opaque  substance  as  a  means 
of  retention.  Still  the  many  good  qualities  of  cement  will  insure  its  use 
for  many  years  to  come,  for  even  if  an  ideal  cement  should  be  dis- 
covered it  will  take  time  to  establish  a  confidence  equal  to  what  we 
now  have  in  the  material  at  present  in  use.  The  question  may  arise 
as  to  what  is  an  ideal  cement.  In  many  cases  what  we  are  now  using 
is  ideal,  that  is  from  a  tooth  saving  viewpoint,  but  its  failure  is  that 
it  does  not  save  itself.  Cement  saves  the  tooth  and  porcelain  protects 
the  cement,  thus  making  a  combination  which  but  for  esthetic  reasons 
would  be  almost  perfect.  Translucency  and  perfect  color  matter 
little  in  some  instances,  but  in  others  they  are  highly  important  and  the 
profession  should  hail  the  advent  of  a  material  having  all  the  necessary 
qualities  as  the  fruition  of  a  long  desire. 

Porcelain  inlays  can  be  made  perfect  in  shade  and  shape  and  the 
texture  may  approximate  tooth  substance  in  a  highly  satisfactory 
manner,  but  immediately  upon  attaching  it  permanently  the  shade  is 
changed  through  the  difference  between  the  three  substances,  all  of 
different  density,  coming  in  close  contact,  namely,  porcelain,  cement, 
and  tooth.  The  cement  being  the  chief  point  of  difficulty,  it  is  im- 
portant that  the  objectionable  features  should  be  reduced  to  the 
minimum. 

It  is  a  poor  cement  that  is  not  at  least  a  preventative.  Many 
resemble  each  other  in  manipulative  qualities  with  the  difference 
of  slow,  medium  and  quick  setting  tendencies.  Some  are  coarse  and 
others  are  fine  and  a  few  have  a  combination  of  many  good  qualities, 
but  with  that  tendency  to  "pack"  under  pressure  which  causes  annoy- 
ance to  porcelain  workers.  A  cement  closely  ground  of  clear  color 
and  medium  to  slow  setting,  having  the  maximum  adhesiveness  with 
the  least  amount  of  powder  is  what  is  recommended  for  a  successful 
operation.  In  addition  to  this,  it  should  have  the  greatest  amount  of 
resistance  to  moisture  during  what  is  usually  called  the  "setting" 
period. 

Shading  a  cement  to  match  the  tooth,  or  to  lighten  or  darken  either  the 
porcelain  or  tooth  or  both  is  quite  troublesome,  and,  at  times,  disappoint- 
ing. It  is  of  considerable  assistance  to  mix  pellets  of  cement  of  various 
shades  and  mount  them  on  a  card.  This  allows  of  comparison  and 
saves  much  time  and  guesswork.  Yellows  are  the  most  required,  and  this 
is  fortunate  because  pure  calcined  oxide  of  zinc  is  yellow,  ranging  in 
degree  of  shade  from  a  canary  color  to  cream  white,  and  its  chemical 
combination  with  phosphoric  acid  is  more  complete  than  when  other- 
wise changed.     The  variations  in  shade  depend  upon  the  product 


294  THE    PORCELAIN    INLAY. 

and  it  is  conceded  that  the  best  quality  of  zinc  oxide  comes  from 
France.  This  is  of  the  lightest  shade,  but  it  is  not  safe  to  assume  that 
the  light  shades  are  all  of  this  origin,  because  manufacturers  sometimes 
produce  these  variations  by  coloring  matter  which  has  a  deteriorating 
tendency.  It  may  be  infinitesimal  in  blues  and  grays,  but  white  is 
made  so  by  oxides  of  aluminum  or  zinc  which  reduce  the  chemical 
union  of  the  powder  and  acid  in  a  marked  degree.  All  phosphate 
of  zinc  cements  are  similar  in  manufacture  and  much  the  same  results 
are  obtained,  although  some  are  better  adapted  than  others  to  use  in 
connection  with  inlays. 

Some  inlay  troubles  are  caused  by  injudicious  selection  of  cements, 
that  is  using  a  quick  setting  cement  instead  of  a  slow  one,  or  vice 
versa.  Another  factor  is  improper  mixing  in  the  way  of  insufficient 
spatulating  which  gives  poor  results  through  non- incorporation  of  the 
two  ingredients.  Cement  mixed  too  thin  will  not  have  the  body  of 
material  required  for  resistance,  with  the  added  danger  of  displace- 
ment during  the  longer  period  which  it  takes  for  setting.  Cement 
mixed  too  thick  prevents  proper  seating  of  the  porcelain  and  a  close 
union,  with  probability  of  fractured  edges  through  endeavors  to  force 
it  to  place.  Quick  setting  cements  should  be  avoided  in  complicated 
conditions.  Slow  setting  cement  has  less  value  on  corners  and  tips, 
for  usually  such  places  have  free  access  and  a  quicker  setting  cement 
will  reduce  the  possibility  of  displacement,  which  is  increased  through 
prominence. 

In  the  past  four  years  much  attention  has  been  given  to  the  new 
silicate  cements  which  are  on  the  market  under  various  names  with 
many  impossible  recommendations,  therefore  a  word  on  this  point 
may  be  of  some  interest  particularly  in  connection  with  porcelain  inlays. 
These  cements  are  nearly  all  produced  in  Germany  and  it  has  been 
my  fortune  to  be  familiar  with  this  material  almost  from  its  origin,  and 
in  that  time  have  formed  conclusions  through  actual  observations 
that  may  be  useful.  These  silicate  cements  have  not  that  perfection 
claimed  by  the  manufacturers  and  agents,  but  they  have  reached  a 
stage  wherein  it  is  safe  to  prophesy  an  ultimate  success,  how  soon, 
it  is  not  possible  to  say.  That  they  meet  all  requirements  at  present 
or  that  they  can  take  the  place  of  porcelain  is  not  worth  argument, 
but  as  an  attachment  they  come  nearer  to  the  ideal  in  appearance  than 
anything  yet  produced.  Their  strength  and  adhesiveness  to  tooth 
structure  cannot  be  compared  with  the  ordinary  phosphate  of  zinc 
cement. 

In  mixing  a  silicate  cement  one  is  impressed  with  its  tenacity  to 


SHADING.  295 

smooth  surfaces,  leading  to  the  belief  that  it  must  be  particularly  appli- 
cable to  porcelain  restorations,  but  in  many  practical  tests  it  is  found 
that  after  a  few  months  this  adhesiveness  has  decreased  and  the  filling 
is  easily  dislodged.  This  being  the  case  its  use  as  a  medium  for  inlay 
attachment  is  somewhat  hazardous.  It  has  a  value  because  of  shade 
and  its  resistance  to  "washing  out,"  but  this  is  counterbalanced 
by  crevicing  and  fracturing  and  changing  appearance  in  many  mouths. 
And  yet  there  are  instances  where  this  material  wears  well  and  after  three 
years  has  almost  the  appearance  of  porcelain,  but  these  cases  are  rare. 

The  writer  has  been  using  a  new  cement  for  a  year  called  "  Tenacit" 
made  exclusively  for  attachment  purposes,  which  is  apparently  the  long 
desired  medium  for  cementing  the  porcelain  inlay  to  tooth  substance. 

It  is  adhesive,  translucent  and  a  resistant  to  the  oral  fluids,  pro- 
ducing a  restoration  so  much  desired  and  hitherto  impossible  because 
of  the  opacity  of  the  dividing  line. 

This  material  is  now  made  in  Germany  and  will  soon  be  on  the 
American  market  and  it  will  no  doubt  increase  the  value  of  porcelain 
restorations. 

SHADING. 

The  color  problem  in  connection  with  inlay  work  is  one  of  much 
inquiry  and  discussion.  It  is  a  phase  of  the  work  most  perplexing 
and  the  rules  given  by  some  authorities  are  both  diversified  and 
difficult,  requiring  close  attention  even  by  the  most  experienced  and 
often  proving  discouraging  to  the  beginner.  The  size  and  position 
of  an  inlay  will  govern  shade  to  such  an  extent  that  consideration  of 
this  fact  is  one  of  the  first  rules.  The  application  of  the  shade  guide 
to  the  tooth  may  lead  to  an  incorrect  conclusion,  because  quantity 
of  material  adds  depth  to  the  shade  and  most  of  the  guides  are  pointed. 
Frequently  the  point  is  placed  against  the  tooth  without  allowing  the 
eye  to  take  in  the  whole  size  and  general  effect.  Thus  when  the  inlay 
is  finished  it  is  found  to  have  a  lighter  appearance  which  is  an  error 
not  readily  rectified.  Overfusing  is  probably  the  cause  of  more 
poorly  shaded  inlays  than  wrong  choosing  of  shade,  therefore  the 
choice  of  something  slightly  darker  is  recommended  particularly 
if  the  operator  has  limited  experience.  A  rule  which  can  be  applied 
more  frequently  to  a  simple  labial  inlay  is  to  choose  a  shade  darker 
and  reverse  the  order  when  applied  to  small  proximal  cases.  Some- 
thing darker  between  the  teeth  will  surely  cause  a  shadow  which  can 
be  avoided  by  lighter  shades.  The  cement  which  is  the  background 
is  an  opaque  substance  and  is  therefore  a  strong  factor  and  one  that 


296  THE    PORCELAIN    INLAV. 

must  not  be  overlooked,  but  even  with  this  consideration  in  mind  the 
most  beautifully  shaded  work  is  sometimes  disappointing.  In  many 
cases,  however,  this  is  corrected  to  some  extent  by  time. 

In  larger  inlays  and  sections  of  porcelain  the  cement  interference 
is  reduced  by  being  overcome  with  volume  of  material  and  stronger 
basal  shade  body  which  is  toned  to  the  desired  shade  by  lighter  tints. 

Various  degrees  of  yellow  are  used  as  foundation  shades  in  the 
majority  of  cases  with  the  possible  exception  of  pulpless  teeth.  These 
teeth  having  decreased  translucency  the  opacity  of  a  solid  mass  is 
not  so  noticeable  and  the  question  devolves  to  one  of  matching  alone. 
And  yet  the  shading  of  such  a  tooth  requires  considerable  artistic 
skill  because  the  operator  must  do  the  blending  to  suit  the  various 
shade  conditions  present  and  which  are  not  to  be  found  on  any  one 
shade  guide. 

Take,  for  instance,  a  large  incisal  contour  embracing  one-fourth 
of  the  tooth  with  pulp  alive,  and  the  shades  may  vary  from  a  deep 
yellow  near  the  gum  to  a  light  yellowish-blue  at  the  incisal.  This 
would  be  matched  up  with  three  shades,  which  are  all  listed  and  ready 
for  the  mixing;  but  if  pulpless  the  neck  portion  might  be  a  brown 
with  a  greenish-blue  center  and  a  lighter  hue  at  the  edge,  thus  showing 
that  considerable  mixing  must  be  done  which  means  guesswork  in 
many  cases.  The  artistic  porcelain  manipulator  is  handicapped  when 
compared  with  a  painter  who  has  his  palette  and  colors  and  desires 
certain  difficult  combinations  to  portray  what  he  sees  or  is  in  his 
mind's  eye.  He  mixes  and  sees  immediate  results,  whereas  with 
porcelain  the  shades  are  powders  with  no  color  guidance  until  the  mass 
is  reduced  to  a  vitreous  substance,  and  then  not  correctly  so  unless 
the  artistic  sense  is  carried  to  a  completion.  A  great  quantity  of 
matter  has  been  written  and  published  in  regard  to  the  proper  way  to 
shade  porcelain  and  many  excellent  rules  are  formulated,  which  if  they 
could  be  carried  to  a  successful  issue  at  all  times  would  reduce  this 
problem  to  perfection,  but  rules  and  directions  are  of  little  value 
without  artistic  skill  to  carry  them  out.  This  cannot  be  bought 
although  it  may  be  acquired  to  some  extent,  and  yet  it  must  be  inate 
in  the  same  ratio  that  mechanics  are  part  and  parcel  of  the  successful 
dentist.  Rules  may  assist  but  they  cannot  always  be  practical.  It  is 
claimed  that  the  most  successful  mode  of  shading  is  to  build  the  inlay 
by  layers  of  different  enamel  shades  which  "break  up  the  absorption 
and  refraction  of  light  rays,"  thereby  giving  an  opalescence  to  the 
inlay  not  to  be  obtained  otherwise.  This  is  excellent  practice  and 
cannot  be  criticised  when  circumstances  favor  this  procedure,  but  there 


PORCELAIN    BODIES.  297 

are  times  when  the  blending  of  shades  will  give  equal  if  not  better 
results  and  the  simplicity  of  blending  is  much  easier  grasped  by  the 
inexperienced.  Outside  of  this  is  the  fact  that  with  one  exception 
all  inlay  materials  are  made  for  blending  and  the  thousands  of  beauti- 
fully matched  inlays  made  with  these  materials  must  prove  the  fact 
that  merit  is  not  limited  to  the  layer  method  alone. 

Dr.  W.  T.  Reeves  originated  this  method  and  to  him  we  owe 
much  valuable  literature  on  this  subject,  therefore  it  will  be  of  interest 
to  reprint  what  is  claimed  by  him  can  be  accomplished  by  observing 
these  three  rules. 

*' First.  A  neutral  translucent-looking  inlay.  Put  colors  on  strong 
enough,  that  when  covered  with  what  might  be  called  an  enamel 
layer  will  allow  the  colors  to  reflect  through,  the  enamel  layer  modify- 
ing and  harmonizing  the  colors.  This  will  give  the  translucent  effect 
so  desirable. 

"  Second.  If  built  of  three  or  more  layers  of  different  bodies  it  will 
break  up  the  absorption  and  refraction  of  light  rays,  so  that  from 
whatever  angle  or  point  of  view  looked  at  it,  it  will  appear  practically 
the  same.  An  inlay  built  all  of  one  body  or  mixture  will  absorb  light 
only  from  one  direction,  and  viewed  from  one  point  will  look  all  right, 
but  from  the  opposite  point  of  view  will  show  as  differently  as  black 
and  white.  An  inlay  in  layers  will  come  very  near  imitating  nature's 
method  of  building  up  a  tooth  and  by  breaking  up  the  direct  absorp- 
tion and  refraction  of  light  rays,  will  come  very  nearly  looking  the 
same  from  all  points  of  view. 

"  Third.  You  overcome  that  great  bugbear  of  most  inlay  workers, 
the  cement  showing  through  after  the  inlay  is  set.  An  inlay  built 
up  in  layers  will  almost  overcome  the  reflection  of  the  cement  through 
from  underneath.  You  will  often  hear  operators  say  they  had  a 
splendid  color  before  the  inlay  was  set,  but  after  it  was  set  the  cement 
killed  it  entirely.  That  was  because  the  inlay  was  baked  all  of  one 
body  and  the  cement  could  reflect  through  from  underneath  as  easily 
as  the  light  was  absorbed  only  in  one  direction  from  above.  The 
three  points  I  claim  for  this  method  are  translucency,  avoidance 
of  shadow,  and  prevention  of  cement  reflection  from  underneath." 

PORCELAIN  BODIES. 

Until  recent  years  the  advancement  of  porcelain  operations  was 
much  retarded  because  of  few  and  unsuitable  materials,  but  now  the 
variety  is  almost  bewildering.  In  fact  it  is  a  question  if  the  market 
is  not  overdone  in  this  respect. 


298  THE    PORCELAIN    INLAY. 

There  can  be  no  objection  to  every  porcelain  operator  having  a 
varied  stock  of  porcelain,  provided  his  experience  has  been  sufficient 
to  enable  a  skillful  discernment  of  the  various  qualities  of  each,  and 
thereby  produce  gratifying  results  by  eliminating  those  of  lesser 
merit  until  he  has  secured  what  in  his  hands  will  give  the  best  basis 
for  general  application,  but  the  beginner  is  likely  to  be  confused  by 
so  many  different  makes. 

The  value  of  a  product  in  the  eyes  of  many  is  the  assortment  of 
shades.  This  of  course  is  natural  if  the  operator  has  had  little  ex- 
perience, but  as  he  becomes  more  skillful  he  finds  that  at  least  half 
the  number  is  sufficient  because  he  has  learned  that  a  little  manipula- 
tion of  a  certain  few  will  give  the  same  results  in  the  majority  of  cases. 
This  statement  will  be  better  appreciated  by  those  who  have  had  to 
contend  with  the  earlier  condition  of  affairs,  when  only  a  few  stronger 
shades  were  available,  and  they  will  also  agree  that  an  ideal  shade 
guide  could  be  limited  to  a  dozen  and  then  readily  cover  all  require- 
ments. The  porcelain  inlay  worker  of  eighteen  or  twenty  years  ago, 
had  much  to  contend  with  and  many  discouragements  to  overcome, 
and  much  of  the  antipathy  to  this  new  branch  of  dentistry  was  no 
doubt  caused  by  the  crude  appearance  of  many  so-called  finished 
operations,  some  of  which  were  far  from  esthetic  whilst  those  having 
that  recommendation  were  cases  fortunate  enough  to  be  within  the 
range  of  two  or  three  varieties  of  continuous  gum  bodies  such  as 
Allen's,  Tee's  and  Close's.  These  gave  a  few  shades  of  yellows 
which  were  regulated  to  a  great  extent  by  heat,  therefore  a  tooth  with 
gray  or  blue  tints  to  be  matched  up  with  yellow  meant  a  discrepancy 
of  shade  which  justified  much  criticism.  Subsequent  events  have 
proven  that  these  efforts  had  merits  because  they  resulted  in  different 
manufacturers  putting  various  porcelain  bodies  on  the  market,  with 
a  larger  number  of  shades  and  varying  degrees  of  fusing  point. 

Porcelain  work  was  increasing  rapidly  in  the  latter  part  of  the 
nineties  and  in  1898  received  a  gratifying  impetus  by  the  introduction 
of  Dr.  Jenkins'  low  fusing  enamels  with  an  outfit  particularly  designed 
for  using  this  material  with  a  gold  matrix,  for  up  to  this  time  platinum 
was  used  exclusively  for  that  purpose.  The  advent  of  these  goods 
and  the  process  of  using  them  was  the  origin  of  the  controversy  still 
existing  in  regard  to  the  superior  virtues  of  low  fusing  porcelain  over 
the  older  and  longer  tried  high  fusing.  This  question  has  been  debated 
in  public  scores  of  times  and  it  is  still  unsettled,  although  the  differ- 
ences of  opinions  are  not  so  positive,  for  adherents  of  both  factions 
are  forced  to  admit  that  each  have  certain  advantages,  which  when 


FURNACES.  299 

properly  recognized  lead  to  the  ultimate  gain  of  the  work.  The 
introduction  of  Brewsters'  material  was  an  advanced  step  for  the  cause 
of  high  fusing  porcelain  and  he  was  the  first  and  only  one  to  give  us 
enamels  with  basal  shades,  thereby  increasing  the  possibilities  of 
translucency  which  was  lacking  in  many  products.  The  writer  under- 
stands that  Brewster's  goods  are  no  longer  on  the  market. 

During  the  past  five  years  the  S.  S.  White  Dental  Co.  have  done 
much  toward  the  advancement  of  porcelain,  having  introduced  a 
variety  of  shades  at  various  fusing  points.  The  Consolidated  Dental 
Co.  have  also  a  splendid  assortment  with  a  fusing  point  sufficient  to 
satisfy  the  most  enthusiastic  advocate  of  high  temperature.  Johnson 
and  Lund's  goods  are  of  the  best  quality  and  the  fusing  point  is  also 
high.  It  is  generally  conceded  that  a  fusing  point  of  2200°  or  2300° 
is  sufficiently  high  and  quite  suited  to  inlay  purposes  and  the  increased 
strain  on  the  electric  muffle  and  the  extra  time  required  for  such  heat 
counterbalanced  the  small  advantage  of  an  extreme  heat  if  such  exists. 
The  following  goods  having  been  thoroughly  tested  can  be  considered 
of  a  standard  quality  and  the  assortment  is  varied  enough  to  suit  any 
demand. 

Whiteley's  19  shades  fusing  about 2300° 

S.  S.  White  Dental  Co.,  26  shades  fusing  about 2300° 

Jenkins  Dental  Co.,  18  shades  (gold  matrix) 155°° 

Consolidated  Dental  Co.,  23  shade 2600° 

Johnson  and  Lund,  25  shades 2550° 

Ash  and  Son,  7  shades 1900** 

FURNACES. 

Porcelain  as  applied  to  dentistry  at  the  present  time  has  assumed 
such  importance  that  it  is  difficult  to  conceive  of  the  fact  that  only 
twenty  years  has  elapsed  since  the  invention  of  the  first  furnace  which 
reduced  the  time  of  fusing  small  pieces  of  porcelain  to  a  matter  of  a 
few. minutes,  and  to  this  fact  we  owe  the  real  birth  of  that  branch  of 
dentistry  which  is  generally  conceded  to  be  a  distinct  advancement. 
There  is  no  doubt  that  tooth  carvers  and  continuous  gum  workers  of 
many  years  back  have  had  visions  of  what  the  present  generation 
enjoys  by  the  adaptation  of  this  esthetic  work,  and  they  have  given 
much  thought  toward  the  solution  of  the  fusing  problem,  for  that  was 
the  obstacle  first  to  be  overcome,  having  recognized  the  futility  of  much 
advancement  while  harnessed  to  the  cumbersome  and  slow  coke  furnace. 

The  quality  of  workmanship  produced  in  this  manner  is  beyond  our 
criticism  which  proves  that  improvements  in  that  direction  were  not 
required,  but  toward  reduction  of  time  and  convenience  so  that  small 
work  could  be  possible  and  with  little  preparation. 


300 


THE    PORCELAIN    INLAY. 


To  Dr.  C.  H.  Land,  of  Detroit,  belongs  the  honor  of  being  the 
inventor  of  the  first  small  furnace  distinctly  different  from  any  other 
and  especially  adapted  for  this  work,  in  which  he  takes  such  an  im- 
portant position  in  its  history.  Much  praise  must  be  accorded  him 
for  his  persistent  efforts  and  inventive  genius. 

This  furnace  was  called  a  "Compound  Gas  or  Gasoline  Furnace" 


Fig.  269. 


and  was  first  described  to  the  dental  public  in  Items  0}  Interest,  Oct., 
1886,  under  the  heading  "Are  Hydro-carbon  or  Gas  Furnaces  a 
Success?"     (Fig.  269.) 

These  furnaces  were  lined  with  fire  clay  with  a  muffle  of  the  same 
material.  The  air  blast  was  supplied  by  a  foot  bellows  and  took 
about  thirty  minutes'  continuous  pumping  to  secure  the  necessary 
heat.     The  results  were  not  always  satisfactory,  as  frequently  the  gas 


FURNACES. 


301 


was  forced  through  the  muffle  causing  "gassing"  which  was  a  diffi- 
culty to  be  contended  with  in  using  any  gas  furnace. 

Four  years  later  the  same  inventor  produced  a  smaller  furnace  of 
the  same  kind  which  was  called  "The  Midget  Blast  Furnace"  and 
was  a  decided  advance  because  the  muffle  was  much  smaller  and 
made  of  platinum,  thus  aflowing  quicker  heating  and  reducing  the 
"gassing,"  tendency  (see  Fig.  270).  These  little  furnaces  could  be 
heated  sufficiently  to  fuse  the  highest  grade  material  in  seven  to  ten 
minutes  and  have  been  a  decided 
favorite  over  all  others  of  the  same 
kind,  and  there  are  many  still  in 
use  at  the  present  time.  In  fact, 
the  writer  did  not  discard  his 
until  eight  years  ago,  because  its 
efficiency  was  in  marked  contrast 
to  the  troubles  of  the  more  modern 
electric.  These  troubles  have  been 
reduced  to  some  extent,  but  entire 
elimination  must  not  be  expected. 

In  the  early  nineties  several 
gas  furnaces  were  marketed,  the 
most  notable  ones  being  Parker- 
Stoddart,  Fletcher,  and  Downie. 

The  application  of  electricity 
to  dental  appliances  became  gen- 
eral in  the  early  nineties  and  when 
Dr.  L.  E.  Custer  invented  the  first 
practical  electric  furnace  in  1894 
the  improvement  was  considered 
to  be  a  marked  advancement,  be- 
cause heretofore  the  fusing  of  por- 
celain by  means  of  gas  meant  labor 


Fig.  270. 


to  produce  the  blast  which  with  its  attendant  noise  was  most  undesir- 
able. Electricity  eliminated  the  possibility  of  "gassing"  the  porcelain, 
a  trouble  which  cannot  be  understood  unless  experienced  and  one 
which  added  much  to  the  discouragement  of  the  early  porcelain 
workers.  This  new  furnace  being  absolutely  noiseless  and  clean  was 
an  addition  to  the  operating  room  and  thereby  a  convenience  much 
appreciated.  Its  form  was  adapted  more  to  the  use  of  continuous  gum 
work  and  is  shown  in  Fig.  271. 

It  is  practically  unchanged  at  the  present  time,  the  only  improve- 


302 


THE    PORCELAIN    INLAY. 


ment  being  in  the  heat  regulation  and  easier  repair  necessitated  by 
wires  "burning  out."  In  fact  the  trend  of  improvement  in  all  dental 
furnaces  from  this  date  forward  has  been  mainly  toward  the  reduction 
of  this  trouble. 

Two  years  after  this  first  electric  furnace,  or  in  1896,  the  Detroit 
Dental  Mfg.  Co.  marketed  the  "Downie"  which  differed  from  the 
former  mainly  in  general  form  of  the  furnace  and  the  mode  of  wiring 
the  muffle. 


Fig.  271. 

The  next  furnace  brought  to  our  attention  was  a  very  small  one 
invented  by  Dr.  Mitchell,  of  London,  and  intended  for  low  fusing  bodies 
as  it  was  practically  useless  for  anything  higher  than  Ash  and  Son  low 
fusing  porcelain.  In  1899  and  1900  there  were  three  more,  viz., 
Hammond,  Peck  and  Gerhardt,  then  the  Pelton  in  1902  and  Price's 
in  1903. 

The  most  recent  addition  to  a  numerous  list  is  Roach's  Auto- 
matic and  Caulkins'  "Revelation"  in  1905.  The  Hammond  had  a 
valuable  distinction  from  all  others  from  the  fact  that  in  case  of  wires 
burning  a  new  muffle  could  be  substituted  immediately.     This  im- 


FURNACES. 


303 


provement  was  a  decided  advantage  and  other  manufacturers  soon 
made  the  same  arrangement.  The  Hammond  is  now  substituted  by  a 
newer  design  made  by  the  S.  S.  White  Dental  Mfg.  Co.  The  Price  was 
introduced  to  the  profession  with  a  pyrometer  attached,  and  this  im- 
provement has  resulted  in  all  the  leading  furnace  manufacturers  at  the 
present  time  having  a  pyrometer  attachment  in  some  form  or  other. 
There  is  very  little  difference  in  the  merit  of  these  various  furnaces, 
therefore  the  intending  purchaser  cannot  be  far  astray  in  a  choice  of  any 
one  mentioned,  although  it  is  important  to  consider  the  amount  of  heat 
developed  on  the  first  step  of  the  rheostat  if  the  dentist  is  using  low  fus- 
ing material,  as  several  furnaces  develop  a  heat  at  that  point  great 
enough  to  destroy  that  material  unless  watched  very  intently. 

For  many  years  porcelain  oper- 
ations were  confined  to  those  for- 
tunate in  having  electricity  or  gas 
conveniences,  relegating  the  practi- 
tioner without  these  advantages  to 
the  rear  of  the  vanguard  of  dental 
progress.  This  may  not  have  been 
a  hardship  to  the  majority,  because 
in  small  places  the  demand  for  por- 
celain work  is  always  limited,  but 
there  are  many  dentists  ambitious 
to  do  all  kinds  of  work,  therefore 
the  introduction  of  the  gasoline 
dental  furnace  by  the  Turner  Brass 
Works,  of  Chicago,  in  1900,  was  a 
decided  step  toward  the  advance- 
ment and  equalization  of  the  pro- 
fession at  large.  The  furnace  is 
simple  of  construction  and  capable 

of  producing  a  heat  sufficient  to  fuse  any  porcelain  and  will  do   it 
quickly  and  safely. 

This  apparatus  with  the  accompanying  soldering  appliances 
enables  the  rural  dentist  to  be  an  up-to-date  practitioner  and  the 
numerous  sales  of  this  furnace  is  a  testimony  that  this  fact  is  appre- 
ciated. 

There  is  also  another  gasoline  furnace  called  the  Brophy,  which 
is  similar  in  construction  and  has  equal  merit  with  the  original.  In 
conclusion  it  is  apropos  to  state  the  fact  that  improvements  in  appli- 
ances for  the  purpose  of  fusing  small  quantities  of  porcelain  quicker 


Fig.  272.  — Lewellan  furnace. 


304  THE    PORCELAIN    INLAY. 

was  applied  on  a  larger  scale  to  the  manufacturing  of  teeth  with  the 
result  that  the  old  fashioned  coke  ovens  are  now  obsolete,  having  been 
replaced  with  the  more  modern  oil  burners,  which  are  quicker,  cleaner 
and  save  much  labor. 

They  are  an  improvement  and  an  enlargement  of  one  made  for 
continuous  gum  by  Dr.  C.  H.  Land,  in  1892.  The  simplicity  of  its 
form  and  amount  of  high  heat  produced  was  one  of  wonderment  to 
the  profession  at  that  time. 

The  fuel  is  the  regular  refined  petroleum  or  "coal  oil"  syphoned 
to  a  burner  at  the  base  of  the  furnace,  which  is  so  constructed  that  a 
natural  draught  is  all  sufficient  to  produce  the  highest  heat  required 
to  fuse  any  porcelain  body.  They  are  absolutely  without  noise  or 
odor  and  very  economical  and  highly  satisfactory  in  smaller  sizes  for 
continuous  gum  work,  but  they  can  only  be  used  where  there  is  a 
chimney  which  is  necessary  for  the  draught.     (Fig.  272.) 

To  Mr,  Lewellan,  of  Philadelphia,  must  be  credited  the  improve- 
ments of  this  furnace  which  has  revolutionized  the  mode  of  fusing 
large  quantities  of  porcelain. 


CHAPTER  XVII. 
CONSTRUCTION  OF  GOLD  INLAYS. 

JOHN  EGBERT  NYMAN,  D.  D.  S. 

Recently  the  construction  of  gold  inlays  has  been  entirely  revolution- 
ized. A  method  has  been  devised  by  Dr.  W.  H.  Taggart,  of  Chicago, 
which  supplants  all  other  methods.  Applicable  alike  to  simple 
and  to  complicated  cavities  in  any  situation,  obtaining  readily  any 
desired  proximal  contour  and  occlusion,  and  with  uniform  certainty 
of  absolutely  accurate  results,  it  may  well  be  styled  "the  best"  method 
of  gold  inlay  processes. 

It  embodies  all  the  factors  that  are  requisite  of  any  method  that 
maybe  termed  "ideal,"  such  as  accuracy  and  permanency  of  results, 
comfort  of  patient  and  operator,  ease  of  manipulation,  economy  of 
time. 

It  is  essentially  a  method  of  accurate  casting  of  gold  inlays,  some- 
thing heretofore  impossible,  but  now  easily  accomplished  by  means 
of  a  marvelously  ingenious  device  for  the  application  of  gas  pressure  to 
molten  gold.  One  of  the  essential  problems  in  this  process  of  casting 
inlays,  which  had  to  be  solved  was  the  obtaining  of  a  mold  which 
should  have  no  joints  or  crevices  about  it;  this  necessitated  a  model 
of  the  inlay  desired,  that  could  be  dissipated  completely  without 
residue,  by  some  means  which  would  not  in  any  way  injure  the  mold. 

Dr.  Taggart  finally  succeeded  in  producing  a  wax  of  which  a 
model  inlay  could  be  made  in  the  cavity  of  the  tooth,  carving  it  to 
the  desired  contour,  proximal  and  occlusal.  It  was  essential  that  the 
wax  become  plastic  at  a  temperature  that  could  be  tolerated  by  the 
tooth,  that  it  would  not  shrink  or  warp  in  cooling,  that  when  cool  it 
would  be  so  hard  that  it  could  be  removed  without  distortion,  but 
would  not  be  so  brittle  as  to  crumble  under  the  carving  instrument, 
that  it  could  be  vaporized  by  heat.  All  these  essentials  were  finally 
obtained. 

Then  there  was  the  problem  of  the  mold.  Of  what  should  it  be 
composed  and  how  constructed?  It  was  essential  that  the  mold 
material  withstand  a  temperature  of  at  least  2100°  F.  or  1170°  C 
(slightly  above  the  melting  point  of  pure  gold)  without  shrinking, 
cracking  or  softening;  that  it  should  be  finer  in  texture  than  any  invest- 

NOTE. — Figs.  274,  275,  276,  278,  279  and  280  have  been  supplied  through  the 
courtesy  of  "Items  of  Interest"  and  are  copyrighted  by  Dr.  H.  J.  Goslee. 

20  305 


306  CONSTRUCTION    OF    GOLD    INLAYS. 

ment  material  with  which  we  were  then  familiar;  that  it  must  present 
an  absolutely  smooth  surface  in  the  mold  cavity;  that  it  should  set 
sufficiently  hard  to  permit  of  manipulation  without  crumbling.  This 
was  finally  obtained  by  a  combination  of  silex  magnesia  and  plaster. 

These  two  factors  having  been  obtained,  there  still  remained  to  be 
devised  some  method  of  forcing  the  molten  gold  into  the  mold  so  that  it 
would  fill  the  mold  to  the  uttermost  corner,  a  rather  difficult  problem 
considering  the  strong  tendency  of  gold  to  "spheroid",  as  it  is  tech- 
nically termed,  or  "ball  up"  when  in  a  molten  or  fluid  condition. 

The  genius  of  Dr.  Taggart,  which  had  solved  two  of  the  problems, 
proved  fully  equal  to  the  third,  and  at  last  after  months  and  months  of 
experimenting  with  nothing  to  aid  him  but  his  own  inventive  ability, 
his  masterly  knowledge  of  physics  and  mechanics,  and  his  faith  that  he 
would  at  last  succeed,  he  did  succeed  in  constructing  a  machine  that 
would  accomplish  all  that  was  to  be  accomplished  and  so  complete  was 
his  success,  that  it  was  absolutely  startling  to  the  profession,  creating  a 
sensation  such  as  had  never  before  been  known. 

It  is  no  exaggeration  to  state  that  in  the  history  of  the  profession 
nothing  to  equal  this  process  in  value  has  ever  been  given  it. 

The  method  is  as  follows :  The  cavity  having  been  prepared,  a  mass 
of  the  special  wax  (which  is  dark  green  in  color  in  order  that  the  slightest 
overlap  on  the  surface  of  the  tooth  may  be  readily  noticed)  sufficiently 
large  to  more  than  fill  the  cavity  is  softened  by  immersion  for  about 
five  minutes  in  water  of  a  temperature  of  from  13 5°- 140°  F. 
or  77°  C.  This  softening  must  be  done  carefully  and  the  wax  must 
not  be  manipulated  until  it  is  softened  through  and  through.  If 
insufficient  heat  is  used  the  wax  will  crack  when  it  is  forced  into  the 
cavity.  If  too  much  heat  is  used  the  surface  of  it  will  become  pasty 
and  will  crumble  when  an  attempt  is  made  to  carve  it.  To  soften  it  in 
or  over  a  flame  must  never  be  attempted  as  the  surface  will  flow  and 
then  become  pasty  while  the  interior  mass  remains  too  hard  to  be 
manipulated.  Until  one  becomes  familiar  with  this  softening  process, 
it  will  be  best  to  use  a  thermometer  to  determine  when  the  proper  heat 
(140°  F.)  has  been  obtained.  A  very  simple  and  efficient  method  of 
softening  the  wax  is  as  follows:  Obtain  a  thin  cork  of  large  diameter 
which  will  fit  into  an  ordinary  drinking  glass  and  yet  project  slightly 
above  the  edge  of  it.  Thrust  three  or  four  large  pins  through  this  at  a 
distance  of  about  half  an  inch  from  the  center.  Pieces  of  wax  are  forced 
slightly  onto  the  points  of  the  pins — the  glass  is  filled  with  water  of  about 
140°  F. — the  cork  is  pressed  lightly  into  the  glass  and  the  pieces  of  wax 
will  then  be  so  immersed  in  the  water  that  the  temperature  is  uniform 


CONSTRUCTION    OF    GOLD    INLAYS. 


307 


on  all  sides  and  in  a  few  minutes  the  wax  will  be  softened  evenly  through- 
out. While  the  wax  is  softening,  let  the  patient  hold  water  as  hot  as  can 
be  tolerated  in  the  mouth  in  the  vicinity  of  the  cavity  so  that  the  tooth 
will  not  chill  the  wax  too  quickly  when  it  is  inserted  in  the  cavity. 

The  mass  of  wax  first  softened  should  be  shaped  up  by  the  fingers 
so  that  it  will  approximately  fit  the  cavity,  then  the  partially  shaped 
mass  is  softened  again  and  pressed  into  the  cavity;  this  will  insure  its 
being  forced  into  every  corner  of  the  cavity  without  cracking. 

The  wax  is  inserted  into  the  cavity  (which  must  be  moist),  pressing 
it  in  with  the  finger  tips  rather  than  with  an  instrument. 

The  patient  is  at  once  instructed  to  bite  into  it  and  to  chew  upon 
it.  It  is  then  hardened  by  chilling  it  with  a  stream  of  cold  water  or 
having  the  patient  fill  his  mouth  with  cold  water  for  a  few  minutes, 


Fig.  273. — Instruments  for  trimming  and  carving  wax  fillings  for  gold  inlays. 
I.  For  occlusal  surfaces.  2,  3,  4.  5,  6.  For  proximal  surfaces  and  trimming 
along  buccal  and  lingual  margins.  7,  8.  For  proximal  surfaces,  cutting  through 
at  contact  point  and  trimming  along  gingival  margins. 

then  with  suitable  instruments  first  carve  the  occlusal  surface 
to  proper  contour,  carving  flush  to  the  marginal  edges,  leaving 
no  overlap  on  the  surface,  the  mass  which  is  wedged  into  the 
proximal  surface  holding  the  filling  in  place  during  this  oper- 
ation. 

The  occlusal  surface  having  been  carved,  with  suitable  in- 
struments proceed  to  carve  the  proximal  surface,  holding  the 
wax  in  place   by  light  pressure  with  an  instrument  on  the 
occlusal  surface.     Do  not  attempt  to  carve  thick  slices  off  the 
wax,  but  simply  shave  it  off  with  a  movement  parallel  to  the 
margin  until  at  last  it  is  carved  flush  to  the  margin  with  no 
overlap  remaining.     The  buccal  and  lingual  sections  should 
be  carved  before  proceeding  to  carve  the  gingival  section,      i 
finally  passing  a  very  thin  instrument  through  the  contact 
point  and  slicing  off  the  portion  which  may  have  squeezed  under  the 
contour  of  the  adjacent  tooth.     (Instruments  suitable  for  this  carving 
are  shown  in  the  accompanying  illustration.)     Fig.  273. 


3o8  CONSTRUCTION    OF    GOLD    INLAYS. 

This  method  is  known  as  the  direct  method.  Many  competent  op- 
erators obtain  splendid  results  by  what  is  known  as  the  indirect  method 
which  consists  of  taking  an  impression  with  modelling  compound 
such  as  that  manufactured  by  the  Detroit  Dental  Mfg.  Co.  or  the  Loch- 
head  Impression  Material,  manufactured  by  Lochhead  of  New  York. 

A  matrix  of  thin  copper  or  German  silver  or  a  cavity  impression  cup 
must  be  used  in  obtaining  the  impression.  The  impression  cups  de- 
vised by  Dr.  F.  E.  Roach  trimmed  and  shaped  according  to  the  cavity 
in  the  case  are  very  useful.  This  taking  of  the  impression  can  be  done 
in  a  remarkably  accurate  manner  provided  the  operator  will  train  him- 
self in  the  technique  of  it,  and  an  accurate  impression  is  absolutely 
essential  to  the  success  of  this  method.  After  the  impression  has  been 
secured,  a  bite  is  taken  in  wax  or  the  softer  modelling  compounds.  The 
impression  is  imbedded  in  plaster,  a  model  is  made,  with  a  pyramidal 
base,  of  "technique  cement"  or  amalgam  (the  writer  preferring  the 
former).  This  model  when  removed  from  the  cavity  impression  is 
trimmed  if  necessary  until  it  can  be  placed  in  the  proper  position  in  the 
bite,  the  pyramidal  base  is  oiled,  and  articulated  models  are  run  in 
plaster. 

The  wax  model  is  made  in  the  model  cavity  and  the  occlusal  surface 
trimmed  to  proper  shape.  Then  the  cement  model  is  removed  from 
the  articulated  plaster  model  and  the  wax  model  carved  to  proper  prox- 
imal contour.  The  gold  inlay  is  then  constructed  after  the  manner  of 
the  direct  method.  After  the  inlay  has  been  cast  it  is  replaced  in  the 
cement  or  amalgam  model  and  polished. 

This  method  obviates  the  difficult  carving  about  the  gingival  margins 
of  a  wax  model  in  the  mouth  in  certain  classes  of  cavities,  which  carving 
is  often  an  exacting  and  anxious  process,  involving  considerable  discom- 
fort to  the  patient.  It  also  obviates  much  of  the  finishing  and  polishing 
that  must  be  done  in  the  natural  tooth  if  the  direct  method  be  used. 
Furthermore,  should  a  casting  happen  to  be  faulty  another  inlay  may  be 
constructed  without  necessitating  another  appointment  for  the  patient 
to  secure  a  second  wax  model.  This  method  also  saves  the  operator 
as  well  as  patient  considerable  time  at  the  chair  and  if  the  operator  has 
a  laboratory  assistant  it  relieves  him  of  many  details. 

This  method  cannot  be  employed  as  successfully  as  the  direct  method 
in  cavities  involving  both  mesial  and  distal  proximal  surfaces  as  well  as 
the  occlusal  surface  in  teeth  of  marked  contour. 

The  writer  employs  the  indirect  method  in  many  cases  and,  technical 
and  theoretical  criticism  to  the  contrary  notwithstanding,  has  seen  re- 
sults in  the  practices  of  Drs.  Tracy,  Gillett  and  Rhein  of  New  York  and 


CONSTRUCTION    OF    GOLD    INLAYS.  309 

Dr.  Knowles  of  Chicago  by  the  indirect  method  which  could  not  be 
adversely  criticized. 

Should  the  cavity  extend  rootwise  considerably  under  the  gum  mar- 
gin it  may  be  necessary  to  adjust  a  matrix  to  secure  an  accurate  mar- 
gin at  the  gingival  section,  this  should  also  be  done  in  complex  cavities 
including  a  large  buccal  or  lingual  section  of  the  tooth  as  well  as  the 
proximal.  In  such  cases  it  is  well  to  note  the  character  of  the  bite 
before  adjusting  the  matrix,  then  carve  the  occlusal  surface  from 
memory,  so  to  speak,  afterwards  remove  the  matrix,  carve  the  buccal 
and  lingual  proximal  sections,  then  while  thoroughly  chilled  have  the 
patient  close  the  teeth  very  carefully,  if  the  occlusion  be  too  high,  note 
the  point  and  carve  it  away. 

In  cavities  which  include  mesial,  distal  and  occlusal  surfaces  it  will 
be  advisable  to  fit  a  band  matrix  which  will  encircle  the  tooth.  This 
may  be  constructed  of  thin  platinum  or  silver,  and  such  a  matrix 
when  properly  adjusted  will  not  interfere  in  the  least  with  the  bite. 

The  writer  has  encountered  some  cavities,  however,  to  which  a 
band  matrix  could  not  be  adjusted  and  without  which  an  accurate  wax 
filling  for  the  cavity  could  not  be  constructed.  One  of  this  character 
which  he  was  called  upon  to  fill  recently  was  a  lower  left  second  molar, 
the  cavity  extending  from  the  mesio-buccal  angle  around  to  the  disto- 
lingual  angle  and  the  gingival  margin  of  which  lay  about  2  mm. 
below  the  gum.  The  pericemental  attachment  was  practically  at  the 
cavity  margin  and  this  would  have  precluded  the  adjustment  of  a 
band  matrix  even  if  the  other  difficulties  to  its  adjustment  could  have 
been  surmounted. 

The  case  was  operated  on  as  follows : 

An  impression  of  the  cavity  was  taken  with  base-plate  gutta-percha, 
it  being  possible  with  this  material  in  a  semi-plastic  condition  to  force  it 
slightly  over  the  cavity  margin  lying  beneath  the  gum.  From  this  im- 
pression a  cement  model  was  constructed,  mounted  in  the  die  cup  of  one 
of  the  swaging  machines  and  a  i/iooo  platinum  matrix  was  swaged  and 
carefully  trimmed  to  the  gingival  margin,  then  a  hole  about  3  mm.  in 
diameter  was  cut  in  the  center  of  the  matrix  and  it  was  re-swaged. 

This  matrix  was  then  adjusted  in  the  cavity  and  trimmed  just 
flush  with  the  gingival  margins,  without  overlap  at  any  point,  then 
a  mass  of  inlay  wax  was  softened  and  pressed  into  the  matrix  while 
in  the  cavity  and  the  patient  was  allowed  to  bite  on  it.  This  was 
removed  from  the  matrix  and  the  matrix  from  the  cavity,  both  matrix 
and  wax  were  carefully  dried,  the  wax  was  then  placed  in  position 
in  the  matrix  and  the  crevice  that  was  found  along  the  gingival  margin 


3IO  CONSTRUCTION    OF    GOLD    INLAYS. 

between  the  wax  and  the  matrix  was  filled  by  carefully  flowing  melted 
wax  into  it  by  means  of  a  small  spatula;  the  wax  filling  now  being 
adherent  to  the  matrix  it  was  replaced  in  the  cavity,  it  was  noted  where 
additional  contour  was  needed  and  wax  was  flowed  on  at  that  point, 
when  the  proper  contour  was  at  last  obtained.  Matrix  and  wax 
filling  were  removed  thoroughly  chilled,  then  with  a  large  spoon  ex- 
cavator, a  concavity  was  cut  in  the  wax  through  the  hole  in  the  center 
of  the  matrix;  this  was  to  provide  for  additional  mechanical  retention 
of  the  inlay  and  may  be  resorted  to  in  any  inlay  where  the  retentive 
shape  of  the  cavity  seems  to  be  inadequate,  and  the  securing  of  ad- 
ditional retention  would  jeopardize  the  stability  of  the  remainder  of 
the  crown  of  the  tooth. 

Recently  Dr.  F,  E.  Roach  of  Chicago  has  devised  an  instrument 
for  hollowing  out  the  wax  models  without  danger  of  distorting  them. 
It  is  a  very  useful  instrument  and  can  be  procured  from  any  dealer. 

Before  attempting  to  hollow  out  the  model  or  to  trim  off  any  over- 
lap which  may  be  found  at  a  point  that  was  not  quite  accessible  to  the 
carving  instruments  the  operator  is  advised  to  mount  the  model  on  the 
sprue-former  as  described  below,  then  the  model  may  be  held  in  a 
manner  that  cannot  damage  the  fine  marginal  edges. 

The  function  of  the  platinum  matrix  in  the  case  just  referred  to, 
was  simply  to  give  a  definite  edge  to  which  the  wax  filling  could  be 
trimmed  to  secure  an  accurate  adaptation  to  this  obscure  margin  so  that 
there  would  be  neither  protrusion  or  recession  at  the  cavity  margin, 
either  of  which  would  probably  have  caused  chronic  gingivitis. 
Subsequently,  the  gold  was  cast  into  this  platinum  matrix  which  became 
part  of  the  permanent  inlay. 

If,  upon  removal  of  the  wax  model  from  the  cavity,  it  is  noted  tfiat 
the  margin  is  faulty  or  indefinite  at  any  point,  this  fault  may  be  cor- 
rected by  chilHng  the  model  thoroughly,  drying  it,  pressing  a  small 
strip  of  parafi&n  upon  the  faulty  margin,  replacing  the  model  in  the 
cavity  and  slowly  pressing  it  to  place;  the  heat  of  the  mouth  while  not 
affecting  to  any  appreciable  degree  the  hard  wax  model  will  thoroughly 
soften  the  paraffin  so  that  simply  the  gap  in  the  margin  will  be  filled 
by  it;  then  chill  thoroughly;  upon  removal  a  definite  margin  will  be 
found  where  it  was  faulty  before. 

In  case  of  pulpless  teeth  additional  retention  may  be  secured 
by  inserting  an  iridio-platinum  post  (about  i8-gauge)  in  the  root 
canal.  This  should  be  inserted  after  the  wax  filling  has  been  carved. 
Heat  the  post  (see  that  it  is  dry  and  slightly  roughened)  and  pass  it 
through  the  wax  filling  into  the  root  canal;  it  should  be  hot  enough 


CONSTRUCTION    OF    GOLD    INLAYS. 


311 


to  melt  the  wax  as  it  comes  in  contact  with  it  so  that  it  will  pass  through 
the  filling  without  force  enough  to  crowd  it  from  the  cavity.  When 
chilled  the  wax  will  be  adherent  to  the  post  and  can  be  removed  from 
the  cavity  by  simply  grasping  the  projecting^end  of  the  post  and  re- 
moving it  and  the  filling  together. 

If  matrices  or  posts  are  used  they  should  always  be  of  platinum 
and  iridio-platinum  respectively,  as  gold  matrices  and  posts  oxidize 


Fig.  275. 

slightly  when  the  mold  is  heated  up  and  the  cast  gold  does  not  adhere 
perfectly  to  them. 

The  wax  filling  having  been  completed  and  removed,  it  is 
washed  in  cold  solution  of  soap  and  water  by  means  of  a  camel's 
hair    or   sable  brush   to   remove  any   film  of   saliva   that   may   be 


Fig.  276. 

adhering  wnich  would  cause  a  faulty  mold,  thoroughly  chilled  in 
ice  water,  then  a  little  brass  rod  about  10  mm.  long  and  2  mm. 
in  diameter,  technically  known  as  a  sprue-former,  is  heated  by  dry 
heat,  and  pressed  into  the  wax  at  either  the  occlusal  or  the  proximal 
surface  (Fig.  274),  preferably  the  latter.  Recently  Dr.  H.  N.  Orr  of 
Chicago  has  devised  a  very  useful  and  ingenious  little  instrument  for 
attaching  the  sprue-former  to  the  wax  model  while  it  is  in  place  in  the 
cavity  of  the  tooth  (see  Fig.  277). 


312  CONSTRUCTION    OF    GOLD    INLAYS. 

It  consists  of  a  split  tube  A  which  holds  asprue  former  with  a  slight 
spring  clutch.  This  is  soldered  to  a  nozzle  C  which  has  its  opening  at 
side  B  instead  of  at  end,  this  opening  extends  through  the  split  tube, 
at  the  butt  end  of  the  nozzle  is  attached  a  rubber  bulb  D  similar  to  the 
bulb  of  the  ordinary  medicine  dropper  and  which  projects  through  an 
opening  in  the  side  of  the  hollow  handle  E.  These  parts  slip  together 
and  are  held  by  friction  clutch  alone. 

The  bulb  D  is  first  filled  with  ice-water — then  a  sprue  former  is 
slipped  into  the  split  tube,  the  wax  model  in  the  tooth  cavity  is  chilled 
and  lifted  from  the  cavity  with  an  explorer;  that  one  may  be  assured 
that  it  will  draw  easily,  then  replaced  in  the  cavity,  and  chilled  again. 
The  sprue  former  is  heated  slightly  at  the  tip  so  that  it  will  imbed  itself 
in  the  wax  model  without  pressing  it  out  of  shape,  the  instant  it  is 
imbedded  slight  pressure  with  the  thumb  on  the  bulb  through  the  side 


Fig.  277. 

of  the  sprue  holder  (which  should  be  held  as  one  would  hold  a  pencil), 
throws  sufiicient  ice  water  on  the  sprue  former  to  chill  it  and  harden 
the  wax  where  it  was  softened  in  imbedding  it,  and  the  wax  model  may 
be  lifted  from  the  cavity. 

It  will  require  a  Uttle  practice  to  accomplish  this  as  it  should  be  done, 
but  once  this  little  skill  has  been  obtained  it  affords  a  splendid  method 
both  of  removing  the  wax  model  and  attaching  the  sprue  former  without 
danger  of  marring  delicate  margins  or  bending  extended  arms  of  the 
wax  model. 


Fig.  278 

After  removal  of  the  wax  model  by  this  method  the  sprue-former  is 
easily  removed  from  the  holder  by  grasping  it  with  a  pair  of  pliers  just 
below  the  split  tube  and  pulling  it  out. 

These  instruments  have  not  as  yet  been  placed  on  the  market  but 
one  can  have  one  made  by  almost  any  instrument-maker.  This  brass 
rod  is  now  inserted  into  the  hole  in  the  center  of  the  base  plate  of  the 
molding  flask  which  consists  of  a  metal  ring,  and  a  base  plate  (Fig.  275). 
Then  the  investment  or  mold  material  is  mixed  to  about  the  consistency 
of  thick  cream.     In  mixing  this  simply  sift  the  compound  into  the  water, 


CONSTRUCTION    OF    GOLD    INLAYS. 


31: 


Fig.  279. 


avoid  stirring  it  so  that  there  will  be  no  bubbles,  complete  the  mixing 
by  revolving  the  rubber  cup  (Fig.  276). 

Dr.  Taggart  has  devised  two  measuring  cups,  one  for  the  water  and 
the  other  for  the  compound  which  gives  just  the  proper  proportions 
(Fig.  278).  The  compound  sets  slowly  so  that  there  is  ample  time 
for  careful,  deliberate  application  of  it  to  the  wax  model.  It  should 
be  applied  with  either  a  small  sable  brush  or  small  pointed  spatula; 
a  little  is  laid  on  at  a  time  and  carefully 
worked  into  all  the  corners  and  angles, 
especially  along  the  lines  of  the  margins, 
then  after  all  the  surfaces  have  carefully 
been  covered,  more  compound  is  added 
until  the  model  is  covered  at  all  points 
with  an  investment  about  2  mm.  thick. 

The  wax  model  should  never  be  chilled 
just  before  this  first  application  of  the 
investment,  instead  it  should  be  dipped  in  tepid  water  to  bring 
it  more  nearly  to  the  temperature  of  the  mouth.  Chilling  the 
model  undoubtedly  causes  it  to  shrink  and  warp  slightly  but  it 
will  return  to  normal  size  and  shape  upon  being  brought  to  what 
may  be  called  a  tepid  temperature — tepid  water  should  also  be 
used  in  mixing  the  investment. 

Then  the  case  appears  simply  as  a  brass 
rod  with  a  mass  of  investment  material  on 
the  end  of  it  (Fig.  279).  The  ring  is  about 
an  inch  in  length,  varying  in  diameter, 
according  to  the  size  of  the  casting  to 
be  made  (for  by  this  process  a  casting  as 
extensive  as  that  of  a  fourteen  tooth  bridge 
may  be  made),  with  a  small  hole  in  one 
side  near  the  base  to  permit  the  surplus 
mold  material  to  escape. 

The  base  plate  is  so  constructed,  that 
while  it  fits  into  the  ring  for  a  couple  of 
millimeters  there  is  also  a  flange  section 
with  a  milled  edge  which  extends  beyond 
the  side  of  the  flask.  In  the  center  of  base  plate,  is  a  dome  and  in 
the  center  of  that  there  is  a  hole  into  which  the  sprue-former  is  in- 
serted. Having  set  the  sprue-former  in  position,  put  the  ring  in 
place  on  the  base  plate  (Fig.  280)  and  fill  it  with  the  mold  material 
or  investment,  slowly  rotating  the  flask  as  you  do  so. 


Fig.  280. 


314 


CONSTRUCTION    OF    GOLD    INLAYS. 


Build  up  an  excess  above  the  top  of  the  flask,  then  press  a  piece 
of  glass  plate  down  upon  it  which  will  force  the  excess  through  the 
little  hole  in  the  side  of  the  flask.  The  glass  plate  is  removed  by 
sliding  it  across  instead  of  lifting  it. 

Recently  Dr.  Taggart  has  devised  a  new  investment  which  may  be 
mixed  so  thin  that  the  model  may  be  placed  in  the  flask  and  the 
investment  simply  poured  in  upon  it,  a  marked  advantage  as  it  sim- 
plifies the  investing.  It  is  not  as  yet  upon  the  market,  however, 
but  will  be  soon. 

When  the  investment  has  set,  the  flask  is  heated  slightly,  then 
grasping  the  milled  edge  of  the  base  plate  it  is  gently  turned.  This 
breaks  the  adhesion  of  the  mold  material  to  it  without  disturbing  the 
surface  and  the  base  plate  and  sprue-former  are  withdrawn  from  the 
mold.  Do  not  invert  the  flask  in  doing  this,  for  if  this  be  done  and 
some  of  the  investment  material  should  flake  off  it  would  drop  into  the 
sprue  hole  and  result  in  a  flaw  in  the  casting.  The  base  plate  should 
be  kept  clean  and  polished  at  all  times,  rubbing  off  the  surface  after 
cleaning  with  a  little  vaseline. 

The  base  plate  and  sprue-former  having  been  removed,  there  will 
be  found  a  cup-shaped  depression  in  the  center  (Fig.  281),  with  a  hole 

leading  to  the  mold.  The  flask  is  placed  over 
the  Bunsen  burner  in  an  oven  which  has  been 
devised  by  A.  C.  Clark  &  Co.,  and  the  case 
heated  slowly,  carrying  the  heat  to  a  point 
where  the  wax  is  ignited.  The  case  is  kept 
at  this  heat  until  not  only  has  the  wax  been 
burned  out,  but  the  residual  gases  therefrom 
have  also  been  combusted.  It  is  highly  im- 
portant that  the  mold  be  kept  intact,  to  obtain 
a  flawless  casting.  To  insure  this,  heat  the 
flask  slowly  and  do  not  subject  it  to  any 
greater  heat  than  is  necessary  to  consume  the  wax  and  its  gases. 

Take  precautions  to  avoid  chipping  the  investment  about  the  con- 
cavity and  the  sprue  hole,  for  if  these  chips  should  fall  into  the  mold 
and  it  frequently  is  impossible  to  remove  them  if  they  do,  they  cause  a 
faulty  casting  and  if  the  fault  be  along  any  of  the  margins,  your  inlay  is 
ruined  beyond  repair. 

The  burning  out  of  the  wax  and  its  gases  being  completed,  the 
flask  is  allowed  to  cool,  then  placed  in  the  flask  holder  of  the  casting 
machine. 

It  may  be  well  to  briefly  describe  the  casting  machine.     It  consists 


Fig.  281. 


CONSTRUCTION  OF  GOLD  INLAYS. 


315 


of  a  device  which  holds  a  100  gallon  cylinder  of  nitrous  oxide,  has  a 
pressure  valve  which  may  be  set  for  the  pressure  desired,  a  dial  pressure 
indicator,  which  registers  the  pressure  under  which  the  gas  is  released, 
a  blow  pipe,  a  compressing  lever,  a  lever  lock,  a  mold  flask  holder, 
and  a  signal  whistle  which  sounds  until  the  escape  valve  of  the  gas 


Fig.  282. — I.  Cylinder  of  nitrous  oxide  gas.  2.  Dial  pressure  indicator.  3  Pressure 
valve.  4.  Signal  whistle.  5.  Automatic  lever  locking  device.  7.  Metal  flask  cover. 
8.  Nitrous  oxide  blowr  pipe.  9.  Mold  flask.  10.  Mold  flask  holder.  12.  Nipple  for 
illuminating  gas  connection.  14,  18.  Flask  holders,  large  and  small,  15,  ig.  Base 
plates  for  flasks  large  and  small  with  sprue-formers  in  place.  16,  17.  Large  and  small 
flasks.     .21.  Control  valve  for  nitrous  oxide  to  blow  pipe.      * 


cylinder  has  been  closed  after  the  casting  has  been  made,  a  very 
valuable  little  device  by  the  way  which  prevents  the  inadvertent  loss 
of  a  cylinder  of  gas  (Fig.  282). 

The  flask  having  been  placed  in  the  flask  holder,  a  button  of  gold 
is  placed  in  the  cup-shaped  depression  of  the  mold  and  the  flame  of  the 
nitrous  oxide  blow  pipe  is  directed  against  it.  The  use  of  the  nitrous 
oxide  blow  pipe  concentrates  a  small  intense  flame  directly  upon  the 


3l6  CONSTRUCTION    OF    GOLD    INLAYS. 

gold,  melting  it  thoroughly  without  affecting  the  surrounding  mold 
as  the  ordinary  gas  blow  pipe  flame  would. 

The  button  of  gold  having  been  melted  until  it  fairly  boils,  the 
compressing  lever  is  brought  down,  thrusting  aside  and  shutting  off  the 
blow  pipe,  forcing  a  metal  cover,  with  asbestos  rim  packing  to  make  it 
pressure  tight,  upon  the  flask  ring  and  releasing  upon  the  molten  gold  a 
gas  pressure  of  about  twelve  pounds  from  the  gas  cylinder,  forcing  it 
into  the  mold  in  the  center  of  the  flask,  the  residual  air  being  driven 
into  the  minute  pores  of  the  mold  investment  ahead  of  the  gold. 

The  various  operations  are  done  automatically  by  the  downward 
sweep  of  the  compressing  lever.  The  whole  operation  is  practically 
instantaneous,  the  molten  gold  has  no  opportunity  to  cool  and  solidify 
until  it  is  forced  into  the  mold ;  the  gas  pressure  is  confined  absolutely 
to  the  mass  of  gold  and  is  sustained  while  it  is  cooling,  and  therein 
lies  the  main  factor  of  success  of  this  method. 

The  flask  is  cooled,  the  investment  broken  out  and  a  gold  casting, 
the  duplicate  of  the  wax  filling  with  a  metal  sprue  attached  is  found. 

The  metal  sprue  is  cut  off  with  a  fine  saw  or  pair  of  nippers,  the 
gold  inlay  is  immersed  in  hydrofluoric  acid  for  a  short  time  to  remove 
the  particles  of  investment  material  that  will  be  found  fused  to  it, 
then  washed,  boiled  in  sulphuric  acid  and  washed  again.  Frequently 
the  outer  surface  will  need  little  or  no  polishing  save  at  the  point 
where  the  sprue  was  attached,  so  perfectly  may  castings  be  made 
by  this  process  if  the  wax  filling  be  carefully  finished  and  all  the 
various  steps  carefully  carried  out. 

Before  attempting  to  try  the  inlay  in  the  cavity,  examine  the  cavity 
surface  of  the  inlay  carefully  for  little  gold  beads  which  may  be  readily 
removed  with  a  fine  sharp  excavator. 

After  trying  in  the  inlay,  if  it  should  be  found  that  the  proximal 
contour  is  insufficient,  this  may  be  added  to  by  simply  flowing  on  a 
little  22-K  solder  at  that  point.  It  has  been  found  by  experience  that 
it  is  best  not  to  reheat  the  flask  before  placing  it  in  the  machine;  it 
must  be  perfectly  dry,  however,  otherwise  there  will  be  a  regurgitation 
of  steam  that  will  either  blow  the  gold  out  of  the  depression  when  it  is 
molten  or  prevent  the  complete  casting,  according  to  the  amount  of 
steam  developed  and  confined. 

Inlays  should  be  cast  the  same  day  that  the  investment  is  made, 
the  results  are  not  so  perfect  when  molds  are  allowed  to  remain  over 
night  before  casting. 

When  small  inlays  are  to  be  constructed,  as  is  often  the  case,  in 
cavities  in  bicuspids  or  the  anterior  teeth,  an  ordinary  pin  may  be  used 


CONSTRUCTION  OF  GOLD  INLAYS.  317 

instead  of  the  regular  sprue-former,  this  pin  is  heated  and  the  point 
of  the  pin  is  placed  in  the  model  while  it  is  in  the  cavity  of  the  tooth, 
then,  after  removing,  a  mass  of  wax  is  placed  in  the  hole  in  the  base- 
plate of  the  flask  and  the  head  of  the  pin  set  into  it. 

Scrap  gold  should  not  be  used  for  casting  inlays.  After  many 
experiments  the  writer  advises  that  the  usual  inlay  be  cast  of  an  alloy 
of  3  parts  24k  gold  and  one  part  22k  solder. 

If  the  inlay  is  very  extensive  and  is  to  be  subjected  to  heavy  stress  of 
mastication,  cast  it  of  an  alloy  of  pure  gold  with  five  per  cent  of  platinum, 
using  a  block  of  magnesia  as  a  melting  block  instead  of  one  of  charcoal. 

After  setting,  but  before  the  cement  has  hardened,  burnish  all 
margins  that  cannot  be  reached  with  a  disk,  then  pohsh  the  margins 
accessible  to  a  disk,  running  the  disk  across  the  margins  at  right  angles 
and  from  the  inlay  towards  the  tooth;  this  spins  out  and  burnishes 
down  a  fine  margin  of  gold  so  thoroughly  that  after  this  polishing  is 
completed  no  cement  is  visible  even  under  a  magnifying  glass. 

As  to  cements  for  setting,  the  writer  advises  the  hydraulic  cements. 

The  effectiveness  of  this  casting  device  may  be  appreciated  when 
you  are  informed  that  by  it  clasps  may  be  perfectly  cast  of  clasp  gold. 

With  this  casting  machine  has  been  cast  gold  crowns  upon  platinum 
bases;  bridge  sections  even  up  to  those  embracing  the  entire  arch;  clasps; 
retaining  splints;  partial  plates;  and  even  full  plates  may  be  cast. 

There  is  no  question  but  what  Dr.  Taggart's  invention  of  appliance 
and  process  marks  a  new  epoch  in  both  operative  and  prosthetic  den- 
tistry; its  value  is  such  that  the  profession  and  the  public  are  under 
obligation  to  him. 

Since  his  demonstration  of  appliance  and  process  other  appliances 
for  casting  have  been  devised  and  presented.  One  very  ingenious  ma- 
chine was  originated  by  Dr.  Jamieson,  of  Indianapolis.  It  casts  by 
centrifugal  force,  the  flask  having  a  swivel  handle  is  hung  from  a  hook 
at  the  end  of  a  horizontal  rod  about  a  foot  long  attached  to  an  up- 
right rod  which  is  revolved  by  the  release  of  a  spring  at  the  rate  of 
about  3000  revolutions  a  minute. 

Another  device  originated  by  R.  C.  Brophy,  of  Chicago,  casts  by 
suction,  a  partial  vacuum  being  created.  Still  another  device,  the  orig- 
inator of  which  the  writer  cannot  ascertain,  casts  by  means  of  steam 
pressure.  A  pad  of  moistened  asbestos  is  jammed  down  upon  the  flask, 
the  heat  of  the  molten  gold  developing  steam  of  sufficient  pressure  to 
force  the  gold  into  the  mold. 

All  these  methods,  however,  are  based  upon  that  of  Dr.  Taggart's, 
in  that  they  employ  a  wax  filling  as  a  model  and  a  flask  for.  the  mold 


3l8  CONSTRUCTION  OF  GOLD  INLAYS. 

identical  with  his,  and  it  may  be  remarked  that  these  were  the  most 
important  factors  of  his  invention,  the  solution  of  the  casting  device 
being  the  least  difficult  of  the  problems. 

The  writer  has  tried  all  methods  and  devices  for  casting  and  after 
many  experiences  states  unequivocally  that  Dr.  Taggart's  appliance 
has  a  wider  scope  and  produces  more  uniform  and  more  perfect  le- 
sults  than  does  any  other.  He  holds  no  brief  for  the  gentleman  and  is 
under  no  greater  obligation  to  him  than  is  any  and  every  member  of 
the  profession.     The  statement  is  made  simply  because  it  is  a  fact. 

This  process  supplants  all  others  because  better  results  can  be 
obtained  with  less  labor  for  the  operator  and  less  loss  of  time  for  both 
operator  and  patient. 

Just  a  word  of  serious  warning  in  closing  this  chapter  to  those 
about  to  employ  this  method.  Do  not  imagine  that  it  discounts  care 
and  skill.  One  may  think  it  is  no  trick  at  all  to  construct  a  wax  filling 
for  a  cavity,  but  let  me  assure  you,  and  experience  will  emphasize  it, 
that  it  requires  all  the  skill  and  patience  you  possess  most  of  the  time  to 
properly  construct  this  wax  filling  and  you  will  probably  be  discouraged 
with  the  process  and  your  endeavors,  until  you  have  mastered  the 
manipulative  technique;  for  faulty  wax  fillings  will  invariably  result  in 
faulty  inlays. 

Skill,  care  and  cleanliness  must  be  observed  in  all  steps  of  this 
process.  Once  the  manipulative  technique  peculiar  to  this  process  has 
been  mastered,  one  will  discover  that  instead  of  discounting,  it  puts  a 
premium  on  individual  skill  and  carefulness.  For  by  this  process 
more  uniform  and  better  results  with  less  labor  may  be  obtained  than 
have  heretofore  been  possible  with  any  process  at  our  command. 


CHAPTER   XVIII. 

THE  TREATMENT  OF  EXPOSED  OR  NEARLY 
EXPOSED  PULPS. 

BY    J.    P,    BUCKLEY,    PH.G.,  D.  D.  S. 
GENERAL  CONSIDERATIONS. 

In  the  practice  of  dentistry  there  are  problems  continually  arising 
wherein  it  is  difficult  for  the  conscientious  operator  to  decide  upon  a 
method  of  procedure  which  will  conserve  the  best  interests  of  the  patient. 
There  is  no  condition  confronting  us  with  greater  difficulty  than  in 
those  cases  where  the  decay  has  extended  to  such  a  depth  that  its  thor- 
ough removal  will  expose  or  nearly  expose  the  pulp.  The  problem  to 
be  solved  here  in  all  such  cases  is  to  decide  whether  it  will  be  best  to 
try  to  save  the  pulp  or  to  anesthetize  or  devitalize  this  organ,  remove  it 
and  subsequently  fill  the  canals. 

There  are  several  important  factors  to  be  considered,  and  upon 
which  will  largely  depend  the  success  or  failure  following  an  attempt 
to  save  the  pulp  after  it  has  actually  been  exposed.  In  an  accidental 
exposure  in  the  preparation  of  a  cavity,  the  chances  for  saving  the  pulp, 
provided  the  injury  has  not  been  too  great,  are  far  more  favorable  than 
if  the  pulp  had  been  exposed  by  the  necessary  removal  of  carious  dentin. 
Our  success  will  also  depend  in  no  small  degree  upon  the  condition  of 
the  pulp  as  well  as  upon  the  general  condition  of  the  mouth  of  the  pa- 
tient in  which  the  exposure  occurs.  If  there  is  congestion  or  any  evi- 
dence of  degeneration  of  the  structural  components  of  the  pulpal  organ 
itself,  it  would  be  futile  to  attempt  to  cap  it,  as  would  be  also  any  attempt 
to  permanently  save  a  pulp  in  the  mouth  of  a  patient  who  was  suffering 
from  some  systemic  derangement  interfering  with  the  general  circula- 
tion, thus  lessening  vital  resistance;  for  in  such  cases  the  pulp  would 
fail  to  receive  from  the  blood  supply  the  necessary  elements  for  the 
restoration  of  its  functional  activity.  The  general  condition  of  the 
mouth  itself  and  the  care  it  receives  daily  from  the  patient,  is  an  essen- 
tial factor  to  be  taken  into  consideration  before  proceeding  to  cap  a 
pulp.  Dr.  S.  A.  Hopkins,  of  Boston,  in  a  carefully  conducted  series 
of  experiments  to  ascertain  the  difference  in  virulency  of  certain  path- 
ogenic bacteria  in  different  mouths,  and  in  the  same  mouth  under 

319 


320    TREATMENT  OF  EXPOSED  OR  NEARLY  EXPOSED  PULP. 

diflferent  conditions,  proved  that  not  only  did  the  germs  proliferate 
more  rapidly  in  neglected  and  uncared-for  mouths,  but  their  pathogenic 
properties  are  greatly  increased. 

There  is  one  class  of  cases  of  pulp  exposure  which  frequently  pre- 
sents in  a  busy  practice  and  in  which  it  is  our  plain  duty  to  make  the 
attempt  to  restore  the  organ  to  its  normal  function,  even  though  the 
conditions  for  doing  so  are  not  altogether  favorable.  I  mean  here 
those  cases  in  the  mouths  of  young  patients  where  the  pulp  is  exposed 
from  decay  and  the  roots  of  the  tooth  have  not  been  fully  developed. 
Every  effort  should  be  made  to  cap  such  a  pulp  and  thereby  save  it, 
if  for  only  a  year  or  two,  for  clinical  experience  has  demonstrated  that 
to  remove  the  pulp  and  properly  close  the  large  openings  in  the  end 
of  the  roots  is,  at  best,  a  difficult  procedure;  that  a  tooth  in  this  condi- 
tion, thus  treated,  is  usually  a  source  of  annoyance  and  its  usefulness 
generally  of  short  duration. 

In  another  class  of  cases  the  author  also  believes  that  we  are  justi- 
fied in  capping  the  pulp.  For  instance,  in  those  cases  of  exposure 
where  for  certain  reasons  it  is  desirable  to  save  the  tooth,  and  on  which 
it  would  be  difficult  to  adjust  the  rubber  dam,  aseptically  remove  the 
pulp  and  thoroughly  fill  the  canals.  I  wish  to  state  here,  however,  that 
I  do  not  mean  to  infer  that  a  pulp  should  be  capped  in  an  anterior  tooth, 
because  of  the  liability  of  the  tooth  structure  discoloring  after  the  pulp 
has  been  removed.  This  phase  of  the  subject  will  be  referred  to  in 
detail  in  a  subsequent  chapter  on  pulp  removal  under  the  preservation 
of  the  color  of  the  tooth. 

From  the  foregoing,  then,  it  should  readily  be  understood  that  no 
set  of  rules  can  be  given,  the  application  of  which  will  surely  lead  to 
success.  Every  case  must  be  studied  and  treated  according  to  the 
operator's  best  judgment  after  having  taken  into  consideration  all 
these  various  factors. 

CAPPING  THE  PULP. 

There  are  several  methods  of  capping  the  pulp,  each  differing  in 
minor  details,  such  as  the  use  of  various  cements,  gutta-percha,  con- 
cave metallic  discs,  etc.,  etc.  In  the  remainder  of  this  chapter  attention 
will  be  directed  to  the  general  precautions  to  be  taken  in  following  the 
different  methods  of  capping;  after  which  one  method  will  be  described 
in  detail  which  has  proved  successful  in  the  author's  practice.  By 
this  I  do  not  mean  to  convey  the  idea  that  all  pulps  which  I  have  at- 
tempted to  save  have  been  rehabilitated  to  their  functional  activity — 
many  have  not;  however,  a  sufficient  number  of  those  thus  treated  have 


CAPPING    THE    PULP.  32 1 

remained  quiet,  and  proved  years  later  to  be  vital,  to  justify  making 
the  attempt  where  the  case  demands. 

Precautions. — The  precautions  to  be  observed  in  following  any 
method  are: 

(i)  By  the  use  of  an  anodyne,  the  hyperemic  pulp,  if  in  this  con- 
dition, must  he  restored  to  normal  before  the  final  capping. 

(2)  The  dentin  overlying  the  pulp  must  he  thoroughly  sterilized. 
It  should  be  noted  here  that  the  usual  perfunctory  method  of  sterilizing 
the  dentin  by  simply  applying  a  germicidal  solution  to  the  cavity  for 
a  few  moments  does  not  sterilize  to  the  degree  necessary  for  successful 
results.  The  lack  of  thorough  sterilization  has,  without  doubt,  been 
the  chief  cause  of  failure.  The  accuracy  of  this  statement  will  be  seen 
when  we  remember  that  our  greatest  success  has  followed  the  capping 
of  pulps  which  have  been  accidentally  exposed  with  a  bur  or  instru- 
ment in  preparing  a  cavity,  although,  in  most  cases,  greater  mechanical 
injury  had  been  caused  than  when  the  exposure  was  due  to  caries  or 
the  removal  of  carious  dentin. 

(3)  Pressure  in  applying  the  material  for  capping,  or  the  cement 
which  covers  the  capping,  must  he  avoided. 

Technique. — After  breaking  down  all  overhanging  edges  of  enamel 
and  removing  as  much  of  the  debris  and  softened  dentin  as  can  be  done 
without  pain  or  injury  to  the  pulp,  the  cavity  should  be  flooded  with  a 
mild,  non-irritating,  antiseptic  solution,  previously  heated  to  the  tem- 
perature of  the  body.  For  this  purpose  the  author  suggests  the  use  of 
peppermint  water  to  which  95  per  cent  phenol  has  been  added  in  the 
following  proportion: 

I^     Phenolis,  f.3  j 

Aquae  menthae  piperitae,  f  §  vj — M. 

Sig. — Use  wherever  a  mild,  non-irritating  antiseptic 
solution  is  indicated. 

This  solution  can  be  further  diluted,  if  necessary,  and  used  with  a 
water  syringe,  before  applying  the  rubber  dam,  thus  adding  comfort  and 
cleanliness  to  the  operation.  The  excess  can  now  be  absorbed  from 
the  cavity  with  cotton  and  the  dam  adjusted.  By  using  some  obtund- 
ing  remedy  ami  a  sharp  spoon  excavator,  or  oftentimes  a  large  round 
bur  in  the  engine,  the  carious  dentin  can  be  removed.  If,  however, 
the  thorough  removal  of  all  the  softened  dentin  would  make  a  large 
exposure,  it  is  best  to  leave  the  layer  overlying  the  pulp  and  depend 
upon  the  sterilizing  agent,  rather  than  to  jeopardize  the  life  of  this 
organ  by  the  injury  thus  produced.  The  delicate  pulp  tissue  will  not 
tolerate  much  abuse  and  remain  quiet,  therefore  if  it  is  injured  to  any 


32  2    TREATMENT  OF  EXPOSED  OR  NEARLY  EXPOSED  PULP 

great  extent  it  had  better  be  removed  at  once.  The  dentin  can  now  be 
sterilized  by  sealing  in  the  cavity,  for  a  week  or  two,  the  following 
remedy  which  is  not  only  germicidal  in  action,  but  possesses  marked 
anodyne  properties  as  well: 

I^ — Menthol,  gr.  xx 

Thymol,  gr.  xl 

Phenolis,  (U.  S.  P.)  f.3  iij— M. 

Heat  the  phenol  and  then  carefully  add  the 

menthol  and  thymol. 
Sig. — Use  as  directed 

This  remedy  is  known  as  the  author's  phenol  compound. 

It  is  best  to  seal  with  a  veneer  of  quick-setting  cement,  previously 
filling  most  of  the  cavity  with  cotton,  thereby  avoiding  pressure  and 
facilitating  the  subsequent  removal  of  the  dressing.  By  this  means 
the  dentin  can  be  thoroughly  sterilized,  and  the  pulp,  if  at  all  hyperemic, 
as  it  is  likely  to  be,  will  return  to  its  normal  condition. 

Thymol  has  a  peculiar  but  favorable  action  on  animal  tissue, 
and  for  this  reason  it  is  incorporated  in  the  prescription.  At  the 
next  sitting,  the  case  giving  a  favorable  history  for  the  interval, 
the  dam  should  always  be  applied,  the  teeth  included  sterilized 
and  the  previous  dressing  carefully  removed,  when  the  exposure 
and  dentin  immediately  over  the  pulp  can  be  gently  covered  with  a 
thin  paste  made  by  mixing  pure  precipitated  calcium  phosphate  with 
phenol  compound,  oil  of  cloves,  or  eugenol.  The  paste  should  be  placed 
on  one  side  of  the  cavity  and  gently  coaxed  over  the  exposure  in  such 
a  manner  as  to  exclude  the  air.  I  desire  to  emphasize  the  importance 
of  covering  the  entire  dentin  immediately  over  the  pulp,  as  well  as  the 
exposure,  with  this  antiseptic  and  non-irritating  paste.  By  this  means 
we  prevent  the  phosphoric  acid  of  the  cement,  used  to  cover  the  paste 
and  to  temporarily  fill  the  cavity,  from  irritating  the  pulp.  It  is  best, 
as  intimated  here,  to  fill  the  entire  cavity  with  cement  and  wait  for  a 
few  months  or  perhaps  a  year  before  inserting  the  permanent  filling 
or  inlay.  Advantage  should  be  taken  of  every  possible  means  of  pre- 
venting subsequent  irritation  to  the  pulp.  For  this  reason  largely  the 
author  uses  precipitated  calcium  phosphate  instead  of  calcined  zinc 
oxid,  which  latter  substance  is  recommended  by  many  writers.  The 
powder  (largely  zinc  oxid)  which  comes  with  a  package  of  cement  is 
supposed  to  be  chemically  pure.  Those  who  are  familiar  with  the 
science  of  chemistry,  however,  know  that  arsenic  is  found  associated 
in  nature  with  many  of  the  metals,  among  which  is  zinc;  and,  while  it 
can  be  done,  it  is  difiicult  to  obtain  these  metals  or  their  oxids  free  from 


CAPPING    THE    PULP.  323 

arsenic.  It  is  well,  especially  in  those  cases  where  the  pulp  is  not 
quite  exposed,  to  add  a  small  amount  of  either  aristol  or  europhen  to  the 
paste.  These  are  iodin  compounds  and  are  used  as  substitutes  for 
iodoform.  Both  are  tasteless,  practically  without  odor,  and  insoluble 
in  water,  but  soluble  in  the  oil  used  as  the  vehicle  for  the  paste,  there- 
fore only  a  small  amount  should  be  added. 

In  closing  this  chapter,  I  desire  to  emphasize  the  importance  of 
studying  carefully  the  conditions  as  found  in  each  case;  and  to  say  that 
the  opportunity  here  for  exercising  good  judgment  is  very  great,  and 
that  there  is  a  satisfaction  in  realizing,  whether  we  succeed  or  fail  in 
our  effort  to  save  the  pulp,  that  we  did  our  duty  as  we  saw  it. 


CHAPTER   XIX. 

THE  ANESTHETIZATION  AND  DEVITALIZATION 

OF  PULPS,  THEIR   REMOVAL,  AND  THE 

SUBSEQUENT  TREATMENT. 

BY    J.    P.    BUCKLEY,    PH.G.,  D.  D.  S. 
GENERAL  CONSIDERATIONS. 

Embryologists  claim  that  when  the  roots  of  a  tooth  are  fully  devel- 
oped, the  pulp  has  no  further  function  to  perform.  If  this  theory  can 
be  accepted  as  correct,  and  I  think  that  it  is  quite  well  established,  it 
would  appear  from  the  large  percentage  of  failures  following  the  most 
careful  methods  of  pulp  capping,  that  the  safest,  and,  therefore,  the 
best  practice  would  be  to  destroy  the  vitality  and  remove  the  pulp  in  all 
cases  where  this  delicate  and  susceptible  tissue  had  been  previously 
irritated  for  any  great  length  of  time,  unless,  as  explained  in  the  fore- 
going chapter,  there  was  some  special  reason  for  attempting  to  restore 
the  organ  to  its  functional  activity.  From  sad  past  experience  the 
author  has  been  led  to  adopt  this  general  practice.  By  this  I  do  not 
wish  to  convey  the  idea  that  it  is  advisable  or  necessary  to  miscellane- 
ously or  ruthlessly  destroy  pulps,  for  such  is  not  the  case.  It  is  the 
plain  duty  of  every  dental  practitioner  to  save  th,e  pulps  of  teeth,  if  it 
can  be  done  with  any  reasonable  degree  of  success.  Dentists  are 
delving  into  pathology  today  more  than  ever  before;  and  a  knowledge  of 
the  pathology  of  the  pulp,  whereby  one  may  be  able  to  interpret  the 
clinical  symptoms,  is  essential  in  arriving  at  a  proper  decision  as  to 
whether  the  pulp  should  be  saved  or  destroyed.  There  are  many 
conditions,  however,  which  necessitate  the  removal  of  the  pulp,  such  as: 

(i)  Dental  caries,  or  the  invasion  of  pathogenic  bacteria  and  the 
absorption  of  toxins.  This  is  the  most  prolific  source  of  pulp  irrita- 
tion. 

(2)  Mechanical  irritation,  due  to  such  causes  as  abrasion,  thermal 
changes,  close  proximity  of  metallic  fillings,  injudicious  regulating, 
excessive  grinding,  etc. 

(3)  Calcific  deposits,  or  pulp  nodules  within  the  pulp  itself.  These 
calcific  bodies  result  from  slight  but  continued  irritation  of  the  pulpal 
organ. 

(4)  Crowning  teeth  and  filling  large  cavities.     It  is  usually  diffi- 

325 


326        THE    ANESTHETIZATION    AND    DEVITALIZATION    OF    PULPS. 

cult  to  grind  a  vital  tooth  sufficiently  to  adjust  the  band  for  a  crown 
properly,  without  irritating  the  pulp  and  thus  endangering  its  life. 
Sometimes  in  filling  teeth  it  is  advisable  to  remove  the  pulp  in  order  to 
properly  anchor  a  large  filling  or  inlay. 

(5)  Pyorrhea  alveolaris.  Frequently  in  treating  this  disease  the 
best  results  can  be  accomplished  by  removing  the  pulp  and  thereby 
throwing  the  entire  circulation  to  the  sluggish  pericemental  mem- 
brane. 

Factors  to  he  Observed  in  Removal  0}  Pulp. — Having  considered 
all  of  the  conditions  and  deciding  that  the  removal  of  the  pulp  is  in- 
dicated, the  method  by  which  this  can  be  accomplished  with  the  least 
inconvenience  to  the  patient  and  to  the  operator  is  the  most  important 
consideration.  Whatever  method  is  employed  in  the  removal  of  pulps 
from  teeth  and  the  subsequent  treatment,  there  are  at  least  three  fac- 
tors to  be  observed,  viz.: 

(i)  Establish  and  maintain  asepsis  in  performing  the  operation. 

(2)  Preserve  the  color  of  the  tooth. 

(3)  Thoroughly  fill  the  root. 

METHODS. 

I.  Anesthetization. — In  the  author's  opinion  a  very  satisfactory 
method  of  removing  pulps  from  teeth,  to  both  patient  and  operator, 
all  things  considered  and  conditions  being  favorable,  is  to  anesthetize 
the  tissue  by  the  use  of  various  strength  solutions  of  local  anesthetic 
agents.  The  solutions  are  forced  or  carried  through  the  dentin  and 
into  the  pulp  by  means  of  pressure  or  the  electric  current. 

(i)  Pressure  Anesthesia. — By  pressure  anesthesia  is  meant  the 
process  of  anesthetizing  the  pulp  by  forcing  solutions  of  local  anesthetics, 
usually  cocain  hydrochlorid,  into  the  tissue  by  means  of  pressure.  The 
pressure  is  applied  either  by  using  unvulcanized  rubber  or  gutta  percha, 
and  a  blunt  instrument,  or  by  specially  devised  instruments  for  this 
purpose.  There  are  many  such  instruments  on  the  market ;  and  while 
they  are  often  an  aid  in  accomplishing  the  ultimate  result,  they  are  not 
an  absolute  necessity. 

The  rubber  dam  should  be  employed  in  every  case  where  it  is  pos- 
sible to  adjust  it,  and  the  teeth  included  sterilized.  In  cases  where  the 
dam  cannot  be  adjusted,  it  would  doubtless  be  best  to  remove  the  pulp 
by  the  devitalization  method,  to  which  reference  will  be  made  later  in 
this  chapter,  for  in  using  the  method  under  consideration  care  must  be 
taken  to  prevent  pericementitis  following  the  operation;  and  one  of  the 
precautions  to  be  observed  in  preventing  this  result  is  to  thoroughly 


METHODS.  327 

sterilize  the  cavity  before  applying  the  pressure.  It  should  be  remem- 
bered that  the  majority  of  canals  which  contain  live  pulps  are  sterile, 
generally  speaking,  and  if  they  become  septic  at  any  time  before  the 
root  is  filled,  it  is  the  fault  of  the  operator.  Thus  the  importance  of 
always  adjusting  the  rubber  dam,  using  sterile  instruments,  and  having 
in  a  convenient  and  conspicuous  place  an  aseptic  doily  on  which  to 
wipe  the  blood  and  dry  the  instruments  used. 

Attention  is  again  directed  to  the  fact  that  the  usual  custom  of  apply- 
ing coagulating  agents,  such  as  phenol,  cresol,  etc.,  to  the  cavity  for  a 
few  seconds,  does  not  sterilize  the  dentin  to  the  degree  desired.  The 
best  results  are  accomplished  by  employing  germicidal  agents  which  are 
soluble  in  water.  In  cavities  where  the  decay  is  not  too  deep,  the  den- 
tin can  be  sterilized  by  the  use  of  a  10  per  cent  solution  of  formaldehyd 
to  which  5  per  cent  of  sodium  borate  (borax)  or  sodium  carbonate 
has  been  added.  Where  the  decay  is  near  the  pulp  this  solution  is 
liable  to  cause  pain,  in  which  case  the  same  result  can  be  accomplished 
by  the  use  of  a  1:500  solution  of  mercury  bichlorid.  In  using  the 
latter  solution  the  pliers  on  which  the  remedy  is  applied  should  be 
wiped  immediately  on  an  aseptic  doily  to  prevent  the  mercury 
from  acting  upon  the  instrument.  One  of  the  best  solutions  with 
which  to  chemically  sterilize  the  dentin,  especially  in  those  cases  where 
the  cavity  has  previously  been  filled  and  the  tubuli  are  closed  and  per- 
haps there  is  secondary  dentin,  is  a  25  per  cent  solution  of  sulphuric 
acid.  Dr.  Geo.  W.  Cook,  of  Chicago,  recommends  using  pure  sul- 
phuric acid  for  this  purpose.  The  solution  can  be  applied  to  the  floor 
of  the  cavity,  being  careful  not  to  get  the  agent  on  the  crown  of  the 
tooth.  After  a  few  minutes  the  excess  can  be  neutralized  with  a  solu- 
tion of  sodium  bicarbonate.  After  the  dentin  is  sterilized  the  cavity 
should  be  desiccated  with  warm  alcohol  and  gentle  heat,  when  we  are 
ready  to  use  the  anesthetizing  solution.  Before  taking  up  the  technique 
of  this  method,  however,  I  desire  to  emphasize  the  importance  and 
necessity  of  cavity  sterilization.  In  our  discussion  later  of  the  devitali- 
zation method,  it  will  be  pointed  out  that  the  carious  and  infected 
dentin  can  be  completely  and  painlessly  removed  after  the  devital'zing 
agent  has  been  applied,  thus  mechanically  sterilizing  the  cavit} ;  but 
in  the  anesthetization  method  the  infected  dentin  is  sensitive  and  can- 
not be  removed  without  unnecessarily  producing  pain.  The  dentin 
in  this  case  must,  then,  be  sterilized  by  chemical  means,  for  to  force 
the  anesthetizing  solution  through  the  dentin  without  previously  ster- 
ilizing it,  means  the  forcing  of  microorganisms,  and  perhaps  poisonous 
ptomains,  into  the  pulp  tissue  and  many  times  into  the  tissue  surround- 


328        THE    ANESTHETIZATION    AND    DEVITALIZATION    OF    PULPS. 

ing  the  apical  end  of  the  root,  for  it  is  difficult  to  force  the  solution  to, 

and  only  to,  the  apex;  thus  too  much  pressure  and  the  lack  of  thorough 

sterilization  constitute  a  prolific  source  of  pericementitis  following  the 

removal  of  pulps  by  this  method. 

With  the  cavity  thoroughly  sterilized  we  are  now  ready  to  use  the 

anesthetizing  solution,  which  should  be  made  at  the  time.     For  this 

purpose  the  crystals  of  cocain   hydrochlorid,   previously  powdered, 

should  be  used  as  the  base,  and  freshly  distilled  or  boiled  water  as  the 

vehicle.     In    my  own  practice  I  use  cocain  hydrochlorid  points  as 

the  base  and  my  regular  local  anesthetic  solution  as  the  vehicle  for 

making  the  stronger  solution.     A  prescription  for  the  regular  local 

anesthetic  solution  here  follows: 

I^ — Cocainae  hydrochloridi,  gr.  vj 

Phenolis,  m.  ij 

Sodii  chloridi,  gr.  j 

Aquae  menthae  piperitae,  f.  §  j — M. 

Sig. — Use  as  a  local  anesthetic  for  hypodermic  injections. 

The  cocain  hydrochlorid  points  not  only  insure  a  pure  specimen 
of  the  drug,  but  facilitate  making  the  solution,  as  they  are  so  read- 
ily soluble.  There  is  no  advantage  in  using  the  above  solution  over 
distilled  or  boiled  water  or  freshly  prepared  peppermint  water,  except 
that  the  solution  is  always  at  hand  in  a  convenient  container  and 
is  sterile. 

The  thumb  and  forefinger  with  which  cotton  is  to  be  wrapped 
around  the  broach  should  be  sterilized  by  dipping  a  large  pledget  of 
cotton  in  the  10  per  cent  formaldehyd  or  i :  500  mercury  bichlorid 
solution  and  rolling  this  between  the  thumb  and  finger.  A  small 
amount  of  the  alkaloidal  salt  is  now  placed  on  a  clean  glass  slab  and  a 
pledget  of  cotton,  dipped  in  the  vehicle  selected,  a  few  drops  of  which 
have  previously  been  placed  on  one  end  of  the  glass  slab  or  in  a  clean 
glass  watch  crystal  or  other  container,  is  gently  placed  in  contact  with 
the  drug,  when  the  latter  readily  dissolves,  making  a  strong  solution. 
It  is  never  necessary  to  make  a  saturated  solution,  for  oftentimes  better 
results  will  be  obtained,  especially  if  the  solution  is  to  be  forced  through 
the  dentin,  if  the  strength  of  the  solution  approximates  only  4  or  5  per 
cent. 

The  cotton  thus  saturated  is  placed  in  the  cavity  as  nearly  over  the 
pulp  as  possible.  A  piece  of  unvulcanized  rubber  which  will  approx- 
imately fill  the  cavity  is  selected  and  passed  through  the  flame.  There 
are  two  objects  in  doing  this:  It  sterilizes  the  rubber,  and  also  makes 
it  more  pliable  in  which  form  it  conforms  readily  to  the  cavity  of  the 
tooth.     The  rubber  is  now  placed  in  the  cavity,  and  by  means  of 


METHODS.  329 

gentle  but  firm  pressure  with  a  suitable  blunt  instrument  the  solution 
is  forced  through  the  dentin  and  into  the  pulp.  If  there  is  any  evidence 
of  pain  as  the  pressure  is  applied,  it  should  be  stopped  for  a  moment, 
but  never  released.  The  slight  pain  is  only  momentary  and  is  an  in- 
dication that  the  solution  is  bemg  confined  under  the  pressure,  which 
is  essential  for  the  success  of  this  method.  In  lower  teeth,  or  other 
favorable  cases,  a  cocain  hydrochlorid  point  may  be  placed  directly 
in  the  cavity  and  the  moist  cotton  added,  making  the  solution  therein. 
It  may  be  necessary  in  those  cases  where  there  is  considerable  dentin 
between  the  cavity  and  tlie  pulp  to  make  two  or  three  applications  before 
the  pulp  is  reached  without  pain,  after  which  one  application  should 
complete  the  thorough  anesthetization  of  the  organ.  After  the  first 
application  a  small  depression  can  be  drilled  into  the  dentin  toward  the 
pulp,  in  which  the  solution  can  subsequently  be  placed,  thereby  aiding 
materially  in  confining  the  solution  under  the  pressure.  When  an  ex- 
posure exists  it  requires  but  little  pressure  to  anesthetize  the  pulp.  In 
these  cases  the  cocain  hydrochlorid  can  be  placed  in  the  cavity  near  or 
over  the  exposure  and  the  pulp  gently  pricked  with  a  sharp  explorer, 
causing  it  to  bleed;  this  if  done  carefully  will  produce  very  little  pain. 
The  blood  will  dissolve  the  cocain  hydrochlorid,  when  pressure  can  be 
applied  and  the  pulp  anesthetized.  In  doing  this,  however,  there  is 
greater  danger  of  forcing  the  blood  into  the  tubuli  of  the  dentin  of  the 
crown  of  the  tooth,  thereby  making  it  more  difficult  to  remove  the  blood. 
Care  should  also  be  taken  not  to  force  the  solution  any  further  than  is 
necessary  for  the  painless  removal  of  the  pulp,  for  it  should  be  noted 
here  again  that  cocain  is  a  general  protoplasmic  poison,  and  if  even 
weak  and  sterile  solutions  are  forced  past  the  apices  of  the  roots  peri- 
cementitis is  almost  sure  to  follow. 

When  the  pulp  is  anesthetized  the  pulp  chamber  should  be  opened 
into  in  such  a  manner  as  to  expose  the  canals.  This  is  best  accom- 
plished with  a  large  round  or  inlay  bur  by  means  of  which  the  entire 
roof  of  the  chamber  can  be  obliterated.  In  opening  into  the  pulp 
chamber  of  molar  teeth  care  should  be  taken  not  to  disturb  the  floor 
of  the  chamber,  for  by  so  doing  we  are  liable  to  add  to  the  difficulty  of 
entering  the  canals  with  a  broach.  While  we  are  never  justified  in 
drilling  unnecessarily  for  the  purpose  of  freely  exposing  the  canals, 
it  is,  if  necessary,  far  better  to  weaken  the  crown  of  the  tooth  somewhat 
by  this  means  rather  than  leave  a  portion  of  the  pulp  in  an  inaccessible 
canal  which  may  decompose  and  subsequently  cause  an  abscess. 

The  selection  of  a  proper  broach  is  an  important  matter.  Every 
broach  should  be  tested  before  entering  the  canal.     This  can  be  done 


330         THE    ANESTHETIZATION    AND    DEVITALIZATION    OF    PULPS. 

by  bending  it  in  various  directions.  If  the  broach  is  weak  in  any 
particular  place  it  can  be  detected  by  this  means;  thus  we  avoid  break- 
ing the  broach  in  the  canal,  the  removal  of  which  is  often  a  difficult 
procedure.  Many  good  operators  claim  to  be  able  to  remove  all  pulps 
by  using  a  smooth,  three-cornered  broach  on  which  a  few  threads  of 
cotton  are  wound.  Others  use  twist  or  spiral  broaches.  In  all  large 
canals  the  author  has  had  the  most  satisfaction  from  the  use  of  a  barbed 
broach.  The  broach  should  be  gently  worked  along  the  side  of  the 
canal  as  far  as  it  will  go  without  using  too  much  force,  twisted  once  or 
twice  to  entangle  the  pulp,  and  then  withdrawn.  By  this  means  the 
pulp  can  be  removed  from  large  canals  in  its  entirety. 

In  the  removal  of  live  pulps  by  the  anesthetization  method,  there 
necessarily  would  be  more  hemorrhage  than  in  those  cases  where  the 
pulp  was  devitalized  before  attempting  to  remove  it.  However,  the 
control  of  hemorrhage  is  not  as  difficult  a  procedure  as  many  writers 
have  led  us  to  believe.  In  most  cases  the  hemorrhage,  if  undisturbed, 
will  be  checked  by  nature's  method  in  a  few  minutes;  after  which  the 
blood  in  the  cavity  and  canal  should  be  thoroughly  removed.  I  desire 
here  to  emphasize  the  importance  of  removing  the  blood.  One  of  the 
factors  to  be  observed  in  extirpating  pulps  from  teeth  and  the  subse- 
quent treatment,  is  to  preserve  the  color  of  the  tooth.  The  cause  of 
many  teeth  darkening  after  the  pulp  has  been  removed,  can  be  traced 
directly  to  the  failure  to  remove  the  blood  from  the  dentin  of  the  crown 
of  the  tooth.  The  far  too  prevalent  practice  of  wiping  out  the  bloody 
canal  with  a  solution  of  hydrogen  dioxid,  blindly  thinking  the  blood 
can  be  removed  by  this  means,  cannot  be  too  strongly  condemned. 
The  hydrogen  dioxid  simply  decomposes  the  blood  within  the  tooth 
structure,  oxidizing  the  iron  of  the  hemoglobin;  and  the  gases  evolved 
in  the  decomposition  force  this  pigment  into  the  tubuli,  which,  if  left 
(and  it  is  difficult  to  remove  it),  will  cause  the  tooth  to  subsequently 
darken  in  almost  every  instance.  In  a  subsequent  chapter  the  author 
expects  to  show  that  ferric  oxid  is  largely  responsible  for  the  discolora- 
tion of  teeth  from  pulp  decomposition.  Therefore  we  should  avoid 
forming  within  the  tooth  structure  the  pigment  which  we  know  will  dis- 
color teeth.  The  color  of  a  tooth  does  not  depend  upon  the  life  and  vi- 
tality of  the  pulp,  but  upon  the  array  of  colors  in  the  dentin  which  are  re- 
flected through  the  nearly  colorless  and  transparent  enamel.  If,  then,  these 
colors  are  not  changed  by  our  failure  to  remove  the  blood  or  by  the  use 
of  staining  remedial  agents  in  the  subsequent  treatment  following  pulp 
removal,  the  tooth  will  not  discolor. 

To  remove  the  blood  from  the  canal,  alcohol  can  be  used,  or  even 


METHODS.  331 

better  than  this  agent  is  nature's  greatest  solvent,  water.  '  The  water 
should,  of  course,  be  sterile,  and  the  same  specimen  can  be  employed 
here  as  was  used  in  making  the  anesthetizing  solution,  i.  e.,  freshly 
distilled  or  boiled  water,  or  peppermint  water  to  which  two 
minims  of  phenol  has  been  added  to  the  fluid  ounce.  If  convenient, 
a  little  sodium  chlorid  (common  salt)  can  be  added  to  the  water.  Phys- 
iologic salt  solution  (normal  saline)  is  an  excellent  solution  to  use  for 
this  purpose.  By  this  means  the  blood  can  be  completely  removed,  not 
decomposed  in  the  canal  and  forced  into  the  structure  of  the  tooth. 

There  are  many  canals  so  small  and  tortuous  that  even  a  fine 
broach  will  not  enter,  to  any  depth  at  least.  In  these  cases,  after  the 
hemorrhage  from  the  larger  canals  has  been  checked  and  the  blood  re- 
moved, the  pulp  tissue  in  the  small  canals  can  be  disorganized  by  the 
use  of  strong  solutions  of  mineral  acids  or  alkalies.  The  author  pre- 
fers making  a  paste  of  sodium  dioxid  and  absolute  alcohol,  placing  the 
paste  in  the  pulp  chamber  over  the  small  canals,  and  working  it  down 
as  far  as  possible  with  a  smooth  broach.  The  alcohol  gradually  evap- 
orates, when  the  sodium  dioxid  can  be  decomposed  into  oxygen  and 
caustic  soda  by  placing  a  pledget  of  cotton  in  the  cavity  moistened  with 
distilled  water.  After  the  reaction  has  taken  place,  the  alkali  can  be 
neutralized  with  a  weak  solution  of  sulphuric  acid  (2  per  cent).  This 
process  can  be  repeated  until  the  desired  end  is  attained.  There  are 
other  means  by  which  the  same  result  can  be  accomplished,  such  as 
the  use  of  pure  phenolsulphonic  acid,  a  50  per  cent  solution  of  chem- 
ically pure  sulphuric  acid,  strong  solutions  of  sodium  or  potassium 
hydroxid,  or  a  mixture  of  metallic  sodium  and  potassium  (Schreier's 
paste).  These  same  agents,  especially  the  phenolsulphonic  acid,  can 
be  used  to  advantage  for  the  purpose  of  disposing  of  a  remnant  of  a 
pulp  in  larger  canals.  It  is  not  safe  to  anesthetize  this  remnant  by 
means  of  pressure.  The  only  cases  on  record  to  my  knowledge,  where 
toxic  symptoms  have  resulted  from  the  removal  of  a  pulp  by  pressure 
anesthesia,  followed  an  attempt  to  anesthetize  a  remnant  of  a  pulp  or 
in  making  the  second  apphcation  of  the  anesthetizing  solution. 

After  the  pulp  has  been  removed  and  the  canals  dehydrated  with 
alcohol  and  heat,  an  anodyne  treatment  is  indicated.  For  this  purpose 
such  drugs  as  phenol,  oil  of  cloves,  or  eugenol  can  be  employed.  The 
author  suggests  here  the  phenol  compound  to  which  attention  was 
called  in  the  chapter  on  The  Treatment  of  Exposed  or  Nearly  Ex- 
posed Pulps.  In  using  any  of  these  remedies,  especially  the  last 
named,  it  is  best  to  insert  dry  cotton  in  the  canal  and  then  place  a 
pledget  dipped  in  the  remedy  in  the  pulp  chamber  and  seal  with  tem- 


332         THE    ANESTHETIZATION    AND    DEVITALIZATION    OF    PULPS. 

porary  stopping  or  cement.  The  dry  cotton  in  the  canal  will  absorb  the 
moisture  from  the  apical  end  of  the  root  and  the  anodyne  remedy  from 
the  pulp  chamber.  There  is  an  advantage  in  using  the  dry  cotton, 
for  it  is  almost  impossible  to  completely  dehydrate  the  canal  at  this 
sitting.  If  asepsis  has  been  maintained  in  removing  the, pulp  all  that 
is  necessary  is  to  keep  the  canal  in  this  condition  until  the  root  can  be 
filled.  The  canals  should  not  be  filled  at  the  sitting  at  which  the  pulp 
has  been  removed  by  pressure  anesthesia  unless  there  be  some  excep- 
tional reason  for  doing  so.  There  are  many  good  reasons  why  the 
canal  should  not  be  filled  at  this  sitting: 

(i)  While  it  is  our  object  to  force  the  solution  just  sufl&ciently  to  anes- 
thetize the  pulp,  our  main  object  is  to  remove  the  pulp  absolutely 
without  pain,  and  it  is  very  difficult  to  force  the  solution  to  the  end 
of  the  root  without  forcing  it  through  the  apex  and  anesthetizing 
the  tissue  in  the  apical  area  to  some  extent.  With  the  tissue  anes- 
thetized we  would  have  no  guide  as  to  when  the  root  was  thoroughly 
filled. 

(2)  The  tearing  away  of  the  pulp  from  its  connection  at  the  apex 
causes  more  or  less  irritation,  and  a  few  days  should  elapse  to  give 
nature  a  chance  to  readjust  the  condition.  The  root  filling  would 
only  serve  at  this  time  to  further  irritate  the  tissues. 

(3)  Sometimes  with  the  utmost  care  in  removing  the  pulp,  secondary 
hemorrhage  ensues  with  the  formation  of  a  clot  in  the  apical  area, 
causing  soreness,  in  which  case  greater  comfort  can  be  given  the 
patient  by  the  proper  treatment  through  the  root  canal  than  simply 
by  counterirritation  or  external  treatment  only. 

At  the  second  sitting,  the  case  giving  a  favorable  history,  the  canals 
should  be  filled. 

There  are  cases  occasionally  where  nature  does  not  stop  the  hemor- 
rhage as  readily  as  we  desire.  In  these  exceptional  cases  the  hemorrhage 
must  be  stopped  by  artificial  means,  even  at  the  possible  expense  of 
producing  pericementitis.  Cauterizing  agents  are  useful  here.  For 
this  purpose  95  per  cent  phenol,  a  50  per  cent  solution  of  phenolsul- 
phonic  acid,  or  a  15  per  cent  solution  of  trichloracetic  acid,  can  be 
worked  down  into  the  canal  against  the  injured  and  bleeding  tissue, 
after  which  the  anodyne  treatment  is  employed  as  usual.  Where  the 
above  treatment  does  not  produce  the  desired  result,  cotton  saturated 
with  a  fresh  1:1000  solution  of  adrenalin  chlorid  can  be  placed  in  the 
canal  and  with  unvulcanized  rubber  forced  into  the  tissue  beyond  the 
end  of  the  root.  This  should  only  be  used  in  extreme  cases  because  of 
the  soreness  it  is  liable  to  produce. 


METHODS.  333 

In  this  connection  I  desire  to  discuss  the  use  of  solutions  of  adren- 
alin chlorid  as  the  vehicle  for  making  the  anesthetizing  solution,  or 
the  use  of  adrenalin  chlorid  and  cocain  hydrochlorid  tablets  for  anes- 
thetizing the  pulp.  The  adrenalin  chlorid  has  been  suggested  as  a 
means  of  preventing  hemorrhage.  Now,  it  ought  to  be  evident  to  any 
one  who  has  studied  this  subject  that  to  prevent  hemorrhage  by  the  use 
of  any  hemostatic  agent,  it  is  necessary  to  force  the  agent  into  the 
tissue  from  which  the  hemorrhage  comes.  Therefore,  to  get  the 
eflfect  of  the  adrenalin  chlorid  in  removing  pulps  by  pressure  anesthe- 
sia, it  is  absolutely  essential  that  the  anesthetizing  solution  which  also 
contains  the  hemostatic  agent,  be  forced  through  the  apex  and  into  the 
apical  area — the  very  thing  we  have  been  taught,  from  sad  experience, 
not  to  do.  When  we  remember  that  the  majority  of  pulps  we  are  called 
upon  to  remove  are  those  in  which  there  is,  or  has  been,  more  or  less 
pulpitis,  and  when  we  remember  also  that  pathology  teaches  that  this 
condition  is  frequently  associated  with  pericementitis,  it  is  questionable 
whether  or  not  we  ought  to  prevent  hemorrhage  in  removing  pulps 
from  teeth.  For  to  permit  the  escape  of  blood  from  the  hyperemic 
tissue  at  the  end  of  the  root,  is  one  of  the  best  means  of  aiding  nature  to 
readjust  the  abnormal  to  the  normal  condition.  In  case  the  primary 
hemorrhage  has  been  prevented  by  the  use  of  hemostatic  agents,  such 
as  adrenalin  chlorid,  secondary  hemorrhage  is  almost  certain  to  follow 
with  the  formation  of  a  clot,  the  absorption  of  which  in  the  apical  area 
is  an  extremely  slow  and  tedious  process. 

In  removing  pulps  by  pressure  anesthesia  without  employing  in- 
struments devised  for  this  purpose,  the  best  results  are  obtained  in 
cases  where  there  are  four  walls  to  the  cavity,  for  in  this  condition  the 
solution  is  easily  confined  under  the  pressure.  In  proximo-occlusal 
cavities,  the  missing  wall  can  be  built  temporarily  with  gutta-percha 
or  cement.  This  is  seldom  necessary,  however,  if,  in  packing  the 
rubber  in  the  cavity,  care  be  taken  to  cover  the  gingival  wall  first  and 
thus  seal  at  this  point,  then  working  the  rubber  over  the  occlusal  and 
gradually  creating  the  pressure.  Whatever  means  is  adopted  for  the 
purpose  of  confining  the  solution,  we  must  avoid  having  the  solution 
escape  at  the  gingival  margin  of  the  cavity  and  thereby  be  forced  into 
the  gum  tissue  and  pericemental  membrane.  The  cause  of  many  sore 
teeth  following  this  method  of  removing  pulps  can  be  traced  to  care- 
lessness or  ignorance  in  this  regard.  As  stated  elsewhere  in  this 
chapter,  there  are  many  ingeniously  devised  instruments  on  the  market, 
the  use  of  which  is  often  a  material  aid  in  confining  the  solution  under 


334         THE    ANESTHETIZATION    AND    DEVITALIZATION    OF    PULPS. 

pressure  and  forcing  it  through  the  dentin.  The  same  precautions 
should  be  observed  in  using  any  of  these  instruments  as  have  been 
emphasized  in  the  application  of  pressure  by  other  means. 

(2)  Cataphoresis. — Cataphorcsis  is  a  term  applied  to  the  process 
of  carrying  medicinal  agents  in  solution  into  the  various  tissues  and 
organs  of  the  body  by  means  of  the  electric  current.  In  years  past 
there  were  a  variety  of  cataphoric  outfits  on  the  market.  Today  the 
method  is  practically  obsolete.  To  anesthetize  a  pulp  by  this  means 
the  tooth  should  be  insulated  by  the  rubber  dam,  care  being  taken 
that  no  moisture  escapes  from  the  gum.  A  small  pledget  of  cotton 
saturated  with  the  anesthetizing  solution  is  now  placed  in  the  cavity, 
the  positive  electrode  applied  to  the  solution,  and  the  negative  elec- 
trode, moistened  with  water,  applied  to  some  part  of  the  patient's 
body,  usually  the  hand,  thus  completing  the  circuit.  A  steady  and  con- 
tinuous current  is  desired  and  the  perfected  instruments  are  so  devised 
that  the  amount  of  current  can  be  measured.  The  time  required  to 
anesthetize  the  pulp  by  this  means  depends  largely  upon  the  density 
of  the  dentin  and  the  perfection  of  the  instruments  used.  With  the 
pulp  anesthetized,  the  same  method  of  removing  and  the  subsequent 
treatment  is  followed  as  in  pressure  anesthesia.  Cataphoresis,  while 
successful  in  the  hands  of  those  who  mastered  the  technique,  never 
became  popular,  largely  because  of  the  time  required  to  accomplish 
the  result  and  because  of  the  complicated  and  expensive  apparatus 
necessary. 

If  the  method  of  anesthetizing  the  pulp  be  followed  and  the  pre- 
cautions observed  as  detailed  in  this  chapter,  it  will  be  found  that 
there  are  few  pulps  which  will  not  yield  to  the  influence  of  cocain  hy- 
drochlorid.  It  takes  time,  however,  to  adjust  the  rubber  dam,  ster- 
ilize the  cavity,  remove  the  pulp  and  blood  from  the  canal  and  seal  in 
the  anodyne  remedy.  Many  times  the  operator  is  not  able  at  this  sit- 
ting to  give  the  necessary  time  to  complete  this  operation.  There  are 
cases  also  where  the  condition  or  the  location  of  the  tooth  in  the  mouth  is 
such  as  to  make  the  removal  of  the  pulp  more  favorable  by  another 
method  which  will  now  be  considered. 

II.  Devitalization. — In  the  chapter  on  The  Treatment  of  Sensi- 
tive Dentin  under  the  subject  of  escharotics  or  caustics,  reference  was 
made  to  the  fact  that  there  were  many  drugs  belonging  to  this  class  of 
agents  that  could  not  be  employed  in  the  treatment  of  sensitive  dentin, 
for  the  reason  that  they  were  penetrating  and  had  the  same  deleterious 
effect  upon  the  cells  of  the  pulp  tissue  as  upon  the  dentinal  fibrillae. 
Some  of  the  agents  which  cannot  be  used  for  allaying  the  sensitiveness 


METHODS.  335 

of  dentin  are  exceedingly  valuable  and  are  employed  for  the  purpose 
of  destroying  the  vitality  of  the  pulp,  thus  aiding  in  its  painless  removal. 
The  most  prominent  of  these  agents  is  arsenic  trioxid,  (AS2O3),  formerly 
called  arsenious  acid.  The  author  is  again  gratified  to  know  that 
the  latest  edition  of  the  United  States  Pharmacopeia  recognizes  this 
agent  by  its  correct  chemical  name,  for  he  was  never  able  to  understand 
why  a  true  oxid  should  be  called  an  acid  by  our  legal  authority.  Ar- 
senic trioxid  was  introduced  to  the  dental  profession  in  about  1836  by  a 
Dr.  Spooner,  of  Montreal.  The  agent  was  first  advocated  to  be  used  in 
the  treatment  of  sensitive  dentin;  for  Dr.  Spooner  discovered  that  by 
sealing  the  drug  in  a  cavity  for  a  few  days  the  most  sensitive  dentin 
yielded  to  its  influence.  The  fact,  however,  that  nearly  all  teeth  thus 
treated  subsequently  gave  trouble  because  of  the  death  of  the  pulp  and 
the  usual  sequelse,  led  the  profession  to  abandon  this  agent  for  the 
purpose  for  which  it  was  introduced;  but  it  has  ever  since  been  used  as  a 
means  of  destroying  the  vitality  of  the  pulp.  In  fact,  for  years  it  was 
the  only  agent  employed  with  any  satisfaction. 

There  has  been  much  difficulty  experienced  in  the  use  of  arsenic 
trioxid,  largely  because  of  the  uncertainty  of  the  preparations  employed. 
Many  arsenical  preparations  are  on  the  market.  The  white  powder 
can  be  used  by  moistening  a  small  pledget  of  cotton  with  some  liquid, 
such  as  phenol,  cresol,  creosote,  or  oil  of  cloves,  then  by  touching  the 
cotton  to  the  powdered  arsenic  trioxid,  a  sufficient  amount  will  adhere 
which  should  be  transferred  to  the  cavity  and  sealed,  preferably  with 
cement.  It  is  well  for  each  operator  to  select  an  arsenical  preparation 
with  which  he  can  obtain  good  results,  and  then  this  should  be  used 
to  the  exclusion  of  all  others.  By  this  means  only  can  we  become 
thoroughly  familiar  with  the  action  of  the  preparation  employed.  The 
author  prefers  fiber  made  from  a  paste,  a  formula  for  which  is  here 
given: 

I^ — Arseni  trioxidi,  3  j 

Cocainae,  gr.  xx 

Thymolis,  gr.  v 

Lanolini,  q.  s.  ft.  thin  paste  — M. 

Sig. — Apply  a  small  amount  to  the  dentin  immediately 

over  the  pulp. 
Note:     It  is  best  to  color  the  fiber  red  or  pink  with  some 
stable  coloring  pigment. 

I  wish  to  state  here  something  about  the  pharmacy  of  this  pre- 
scription; for  if  the  preparation  does  not  work  satisfactorily,  it  has  not 
been  properly  compounded.  Arsenic  trioxid  is  the  base,  cocain  is  a 
local  anesthetic,  and  when  applied  to  the  pulp  produces  a  condition  of 


336         THE    ANESTHETIZATION    AND    DEVITALIZATION    OF    PULPS. 

analgesia  by  which  the  irritating  action  of  the  arsenic  trioxid  is  without 
efifect,  and  thus  prevents  the  tooth  from  aching  while  the  pulp  is  being 
devitalized.  With  the  fatty  or  oily  vehicle,  lanolin,  it  is  best  to  use  the 
alkaloid,  cocain,  rather  than  the  alkaloidal  salt,  cocain  hydrochlorid; 
and  the  less  the  amount  of  lanolin  used  the  better  will  be  the  action  of 
the  base.  For  this  reason  largely  thymol  is  added.  There  is  a  suffi- 
cient, amount  of  water  in  the  lanolin  to  liquefy  the  crystals  of  thymol, 
therefore  it  requires  but  a  small  amount  of  lanolin  to  make  a  paste 
out  of  the  arsenic  trioxid  and  cocain. 

In  those  cases  where  the  tooth  has  ached  before  the  patient  presents 
for  treatment,  it  is  always  the  best  practice  to  allay  the  pain  for  at  least 
twenty-four  hours  before  attempting  to  devitalize  the  pulp.  In  any 
case,  whether  the  tooth  has  ached  or  not,  before  applying  the  arsenical 
preparation  or  before  adjusting  the  rubber  dam,  it  is  best  to  break 
down  all  overhanging  edges  of  enamel  and  carefully  remove  or  wash 
out  with  a  non-irritating  antiseptic  solution  any  food-stufifs  or  debris 
which  may  be  in  the  cavity.  Food-stuffs  contain  albumin,  and  if  such 
is  in  the  cavity  of  the  tooth  when  the  arsenical  preparation  is  applied, 
the  arsenic  trioxid  will  act  upon  the  albumin,  forming  the  arsenic 
albuminate,  and  thereby  a  certain  amount  of  the  agent  is  neutralized 
or  becomes  inert.  As  much  of  the  carious  dentin  should  also  be  re- 
moved as  can  be  done  without  producing  pain,  for  the  application 
should  be  made  to  a  sensitive  spot  in  the  cavity.  It  is  never  necessary 
to  have  an  exposure  of  the  pulp;  and  in  case  an  exposure  exists,  it  is 
best  to  apply  the  preparation  to  the  dentin  immediately  over  the  pulp, 
rather  than  directly  to  the  organ  itself.  The  preparation  should  be 
covered  with  cotton  or  small  metallic  or  paper  disc  to  prevent  pres- 
sure and  also  to  prevent  the  phosphoric  acid  of  the  cement  from  com- 
ing in  contact  with  the  ingredients  of  the  paste. 

There  are  at  least  four  factors  which  govern  the  length  of  time  an 
arsenical  application  should  remain   sealed  within   a  tooth,   viz.: 

(i)     The  age  and  general  condition  of  the  patient. 

(2)  The  general  condition  of  the  pulp  itself. 

(3)  The  amount  and  condition  of  the  dentin  intervening  between  the 

pulp  proper  and  the  application  of  the  paste. 

(4)  The  climate  or  season  of  the  year,  strange  as  it  may  seem,  influences 

the  action  of  arsenic  trioxid. 

Taking  into  consideration  these  various  factors,  the  arsenical  prep- 
aration should  remain  in  the  cavity  from  two  to  six  days.  At  the 
second  sitting  the  rubber  dam  should  be  adjusted,  the  teeth  included 


METHODS.  337 

sterilized,  and  the  cement  and  paste  removed,  after  which  every  surface 
of  the  cavity  should  be  freshened  with  a  large  round  bur.  This  not 
only  insures  the  thorough  removal  of  the  arsenical  paste,  which,  should 
a  portion  remain,  is  liable  to  produce  pericemental  inflammation,  but 
it  also  mechanically  sterilizes  the  cavity  by  removing  the  carious  and 
infected  dentin.  This  is  important  and  is  an  aid  in  maintaining  asep- 
sis in  the  removal  of  the  pulp.  In  the  author's  judgment  this  is  much 
better  practice  than  to  depend  upon  a  solution  of  dialysed  iron  to  neu- 
tralize the  arsenic  trioxid. 

The  pulp  chamber  can  now  be  opened  into  and  the  pulp  removed, 
observing  practically  the  same  details  as  explained  under  the  anes- 
thetization method.  Oftentimes  in  the  initial  opening  into  the  pulp 
chamber,  and  sometimes  on  entering  the  canal,  after  the  application 
of  arsenic  trioxid,  the  patient  will  experience  some  pain;  but  by  gently 
working  the  broach  up  the  side  of  the  root,  very  little,  if  any,  pain  need 
be  produced  in  removing  the  pulp,  provided,  of  course,  the  tissue  is 
devitalized.  However,  should  pain  be  experienced,  it  is  best  to  seal 
formocresol  in  the  cavity  in  contact 'with  the  tissue  from  three  to  six 
days,  when  it  can  be  removed  without  pain. 

In  connection  with  the  preservation  of  the  color  of  the  tooth,  under 
the  anesthetization  method  the  author  stated  his  objection  to  the  use 
of  hydrogen  dioxid  for  removing  the  blood  from  the  cavity  and  canal. 
It  is  necessary  here  also  to  refer  briefly  to  a  well-established  practice  of 
treating  teeth  after  the  pulps  have  been  devitalized.  Heretofore  it  was 
the  practice  of  many  dentists,  after  removing  the  arsenical  dressing,  to 
flood  the  cavity  with  a  solution  of  dialyzed  iron,  after  which  the  pulp 
chamber  was  opened  into,  usually  producing  some  hemorrhage;  then 
without  any  especial  effort  being  made  to  remove  the  dialyzed  iron  or 
blood,  tannic  acid  in  some  form  was  sealed  in  contact  with  the  pulp  for  a 
week  or  ten  days,  thinking  it  advantageous  by  this  means  to  constringe 
and  toughen  the  tissue  before  attempting  its  removal.  Let  us  consider 
the  rationalism  of  such  treatment.  The  pulp  tissue  in  all  large  canals  is 
sufficiently  tough  to  be  removed  in  its  entirety,  and  it  must  be  disorgan- 
ized or  removed  piecemeal  in  small  canals,  whether  it  has  been  previ- 
ously constringed  or  not.  Hence,  there  is  no  advantage  in  using  tannic 
acid  and  there  is  a  serious  objection.  If  those  who  follow  this  practice 
are  observing,  they  will  notice  that  after  removing  the  tannic  acid 
dressing,  the  pulp  tissue  is  dark  in  appearance.  They  will  also  ob- 
serve that  many  teeth  thus  treated  subsequently  discolor.  The  cause 
for  this  is  found  in  the  fact  that  tannic  acid  and  iron,  in  any  form,  are 
chemically  incompatible,  the  resulting  compound  being  iron  tannate, 


338        THE    ANESTHETIZATION    AND    DEVITALIZATION    OF    PULPS. 

one  of  the  most  insoluble  substances  known  to  chemistry.  In  the 
presence  of  moisture  a  form  of  ink  is  produced  which  is  a  great  staining 
agent  for  dentin,  and  one  that  is  almost  impossible  to  remove  by  any 
known  process  of  bleaching. 

As  has  been  stated  elsewhere  in  this  chapter,  there  are  cases  where, 
for  want  of  time  or  other  reasons,  the  pulp  can  be  removed  to  advantage 
by  devitalization;  however,  when  this  method  is  followed  tannic  acid 
should  not  be  used,  and  every  trace  of  dialysed  iron  (if  used  at  all,  and 
it  is  unnecessary  to  use  it)  and  blood  should  be  removed  with  alcohol 
or  water.  In  those  cases  where  we  are  certain  that  the  pulp  is  all  re- 
moved and  where  the  canals  can  be  thoroughly  dried,  the  root  filling 
can  be  inserted  at  the  same  sitting,  provided  there  are  no  symptoms  of 
pericementitis  in  the  apical  area.  There  are  many  good  reasons,  how- 
ever, for  not  filling  the  root  at  this  time,  some  of  which  have  been 
considered  under  the  anesthetization  method. 

Complications. — In  our  discussion  thus  far  of  the  methods  of  re- 
moving pulps  from  teeth,  we  have  considered  only  favorable  cases, 
selecting  the  method  best  adapted  to  the  case  at  hand.  There  are  many 
instances,  however,  where  it  is  difficult  to  remove  the  pulp  by  either  the 
anesthetization  or  devitalization  method,  at  least  until  the  tooth  is 
placed  in  a  more  favorable  condition.  Oftentimes  in  approximating 
cavities  the  decay  in  one  or  both  teeth  has  extended  far  beneath  the  gum, 
the  rough  gingival  margin  of  the  cavity  acting  as  a  slight  irritant  by 
which  the  gum  tissue  is  stimulated,  causing  it  to  proliferate  until  it 
fills  a  portion  of,  and  in  some  instances  the  entire,  cavity.  In  such 
cases  the  first  consideration  is  to  dispose  of  the  hypertrophied  tissue. 
Where  the  gum  fills  only  a  portion  of  the  cavity  and  the  pulp  of  the 
tooth  is  not  causing  trouble,  the  cavity  should  first  be  enlarged  and 
washed  with  a  warm  antiseptic  solution,  after  which  it  should  be  dried 
as  well  as  possible  and  packed  with  warm  gutta-percha.  But  in  those 
cases  where  the  gum  tissue  occupies  the  entire  cavity,  and  especially 
where  the  tooth  is  aching,  it  should  be  removed  at  once.  This  is  best 
accomplished  by  the  electric  cautery,  as  it  disposes  of  the  tissue,  pain- 
lessly and  without  hemorrhage.  In  the  absence  of  the  electric  cautery 
other  means  must  be  employed.  Hypertrophied  gum  tissue  is  quite 
tough  and  fibrous,  and  if  it  is  elevated  or  pushed  back  by  means  of  a 
flat  instrument,  it  will  usually  be  found  that  the  attachment  at  the  gin- 
gival margin  is  small  and  can  easily  be  severed  by  employing 
gum  scissors  or  a  lancet,  previously  dipped  in  phenol.  It  is  best 
not  to  tell  the  patient  what  you  are  going  to  do,  for  scarcely  any  pain 


METHODS.  339 

will  be  experienced.  The  hemorrhage  in  these  cases  is  usually  pro- 
fuse, but  can  readily  be  stopped  by  cauterization  with  95  per  cent 
phenol,  a  50  per  cent  solution  of  phenolsulphonic  acid,  or  a  15  per 
cent  solution  of  trichloracetic  acid.  The  blood  should  now  be  thor- 
oughly removed,  the  cavity  dried,  moistened  with  eucalyptol  and 
packed  with  gutta-percha,  letting  it  extend  buccally  and  lingually  to 
fill  the  interproximal  space.  The  gutta-percha  can  be  removed  from 
the  interior  of  the  cavity  with  a  heated  flat  instrument.  Quite  often 
the  most  practical  way  of  adjusting  the  rubber  dam  in  these  cases 
is  to  place  the  clamp  on  the  tooth  posterior  to  the  one  thus  packed, 
having  a  single  hole  in  the  dam  include  both  teeth.  The  packing, 
if  properly  placed,  filling  the  embrasure  on  either  side,  will  prevent 
leakage.  The  pulp  can  now  be  removed  by  the  method  which  the 
operator  deems  the  most  feasible. 

There  is  one  instance  in  the  removal  of  pulps  from  teeth,  where 
students  particularly  are  liable  to  make  a  serious  mistake  if  they  are  not 
extremely  careful.  That  is  in  cases  where,  in  large  occlusal  cavities, 
especially  in  lower  firs^  molars  of  children,  the  pulp  has  died  and  the 
decay  has  extended  through  the  bifurcation  of  the  roots,  leaving  rough 
edges  which  continually  irritate  the  tissue,  causing  it  to  proliferate 
and  ultimately  fill  the  cavity.  To  carelessly  force  the  anesthetizing 
solution  into  such  a  cavity,  where  the  pulp  in  the  canals  is  putrescent, 
would  be  the  means  of  causing  an  acute  alveolar  abscess.  The  -appli- 
cation of  arsenic  trioxid  would  mean  the  loss  of  at  least  one  tooth, 
perhaps  one  or  two  on  either  side  of  the  one  to  which  the  application 
was  made,  with  a  portion  of  the  alveolar  process. 

Before  applying  either  the  anesthetizing  or  devitalizing  agent  a 
correct  diagnosis  should  be  made;  we  should  ascertain  definitely  the 
kind  of  tissue  in  the  cavity.  With  a  little  experience  this  is  usually  a 
simple  matter.  The  history  of  the  case  as  related  by  the  patient  will 
often  serve  as  a  guide.  Pulp  tissue  is  generally  more  sensitive  than 
gum  tissue,  and  when  slightly  pricked  with  a  sharp  instrument  bleeds 
more  profusely.  If  the  tissue  proves  to  be  hypertrophied  gum  tissue 
it  can  be  disposed  of  in  the  usual  manner,  the  puncture  closed  tem- 
porarily with  cement  or  gutta-percha  and  the  tooth  treated  as  the  con- 
dition necessitates.  When  this  cannot  be  accomplished,  it  is  neces- 
sary to  extract  the  tooth.  In  cases  where  the  tissue  is  hypertrophied 
pulp  tissue  it  will  generally  be  found  unusually  resistant  to  both  cocain 
hydrochlorid  and  arsenic  trioxid,  and  it  is  sometimes  necessary  to 
resort  to  cauterization,  using  the  electric  cautery  if  possible,  or  employ- 
ing strong  escharotics,  such  as  pure  phenolsulphonic  acid,  which  is  not 


340        THE    ANESTHETIZATION    AND    DEVITALIZATION    OF    PULPS. 

as  painful  here  as  would  naturally  be  supposed,  or  to  the  administra- 
tion of  such  general  anesthetics  as  nitrous  oxid  and  oxygen  in  order  to 
painlessly  remove  the  tissue. 

Quite  frequently  we  find  cases  where  it  seems  almost  impossible 
to  force  the  anesthetizing  solution  through  the  dentin  and  into  the 
pulp,  and  when  arsenic  trioxid  is  applied  it  has  little  or  no  effect.  In 
these  cases  we  can  suspect  that  the  pulp  has  receded  because  of  some 
slight  but  continued  external  irritation  and  the  space  filled  in  with  sec- 
ondary dentin,  the  tubuli  of  which  are  irregular  and  do  not  run  at 
right  angles  to  the  base  upon  which  they  rest,  as  in  the  normal  dentin. 
This  condition  is  more  often  found  in  elderly  patients.  As  a  result 
also  of  external  irritation,  pulp  nodules,  calcific  bodies  of  various 
shapes,  are  sometimes  found  within  the  pulp  itself.  Many  times  in 
removing  the  pulp  in  these  cases,  the  most  painless  and  best  results  are 
obtained  only  by  a  combination  of  both  the  anesthetization  and  de- 
vitalization methods;  for  the  removal  of  these  pulp  nodules  is  often  a 
difficult  procedure.  After  we  have  used  cocain  hydrochlorid  and 
pressure  or  previously  applied  arsenic  trioxid  and  anesthetized  or 
devitalized  a  portion  of  the  pulp,  we  may  be  able  to  reach  the  pulp 
nodule  or  nodules  without  producing  pain.  But  frequently  these 
calcific  bodies  are  agglutinated  and  close  the  mouth  of  the  canal; 
especially  is  this  condition  found  in  molar  teeth.  The  pulp  tissue 
immediately  under  the  nodule  is  extremely  sensitive.  In  such  a  case 
the  anesthetizing  solution  could  not  be  forced  into  the  canal  without 
first  removing  the  obstruction,  and  arsenic  trioxid,  if  applied,  would 
have  no  effect.  These  are  cases  which  require  much  perseverance  and 
patience  on  the  part  of  both  patient  and  operator.  The  nodule  can 
sometimes  be  loosened  by  gently  working  around  it  with  an  exploring 
or  other  suitable  instrument.  The  author  has  met  with  success  by 
taking  a  small  round  bur  and  drilling  past  the  nodule,  care  being  taken 
not  to  puncture  the  root,  then  with  the  engine  running  rapidly  the 
nodule  is  tapped  and  dislodged.  When  the  obstruction  in  the  pulp 
chamber  and  canals  is  removed  the  remaining  tissue  can  be  anesthe- 
tized or  devitalized  in  the  usual  manner.  If  the  devitalization  method 
is  employed  the  arsenical  preparation  can  be  placed  over  the  mouth 
of  the  canal  with  safety;  but  it  is  never  advisable  to  place  the  prepara- 
tion down  in  the  canal.  Nitrous  oxid  and  oxygen  analgesia  will  prove 
valuable  in  these  stubborn  cases. 

Arsenical  Poisoning. — Before  closing  this  chapter  it  may  be  well 
to  consider  the  treatment  of  local  poisoning  by  arsenic  trioxid.  How- 
ever, when  such  treatment  is  necessary  it  is  due  to  carelessness  on  the 


METHODS.  341 

part  of  the  dentist  or  the  patient,  or  both.  It  is  never  necessary  to 
tell  the  patient  what  drug  or  remedy  has  been  used  in  the  treatment  of 
teeth,  many  times  it  is  advisable  not  to  do  so;  but  whenever  an  agent  as 
destructive  as  arsenic  trioxid  is  sealed  within  a  tooth,  the  patient  should 
be  thoroughly  impressed  with  the  importance  of  keeping  an  appoint- 
ment, and  of  returning  before  the  appointed  time  should  any  unto- 
ward symptoms  develop.  The  patient  should  also  be  informed  that 
the  teeth  thus  treated  might  ache  for  a  few  hours,  as  they  sometimes  do, 
even  when  cocain  is  a  constituent  of  the  arsenical  preparation;  but 
that  the  aching  will  be  of  short  duration.  In  case,  however,  the  tooth 
or  gum  becomes  sore,  they  should  be  instructed  to  return  at  once. 

In  those  cases  where  the  arsenical  preparation  is  not  hermetically 
sealed  within  the  tooth  and  some  of  it  gets  on  the  gum  tissue,  remaining 
only  long  enough  to  cause  devitalization,  all  that  is  necessary  is  to 
first  wash  the  part  with  an  antiseptic  solution,  and  then  mechanically 
pick  off  the  dead  or  sloughed  tissue  with  sterile  pliers  until  bleeding  is 
produced,  if  this  is  possible,  after  which  the  part  should  be  disinfected 
and  the  tissue  stimulated.  To  disinfect  the  part,  any  good  disinfectant 
can  be  used.  Nothing  is  better  here  than  the  official  3  per  cent  solu- 
tion of  hydrogen  dioxid.  As  a  means  of  stimulating  the  cells,  iodin 
compounds  are  useful.  The  Pharmacopeia  recognizes  a  compound 
solution  of  iodin  (5  per  cent)  which  can  be  applied  by  first  drying 
the  part.  After  removing  the  dead  cissue  and  disinfecting,  the  author 
prefefs  applying  euroform  paste.  A  prescription  should  also  be  written 
for  an  antiseptic  mouth  wash  with  which  the  patient  should  keep  the 
mouth  as  clean  as  possible.  The  treatment  can  be  repeated  as  often  as 
the  case  necessitates;  usually  one  or  two  treatments  will  suffice. 

In  those  severe  cases  where  the  arsenic  trioxid  has  penetrated  to 
and  devitalized  the  process  as  well  as  the  gum,  the  first  treatment  is 
surgical.  After  washing  with  an  antiseptic  solution,  the  affected  proc- 
ess should  be  removed  with  a  suitable  bur  in  the  engine.  It  may 
be  necessary  in  extensive  cases  to  extract  the  tooth,  after  which  the 
treatment  is  practically  the  same  as  has  been  outlined  above.  Some- 
times there  is  pain  following  the  surgical  removal  of  the  affected  proc- 
ess. In  this  case  the  euroform  paste  will  act  as  a  specific  absolutely 
controlling  the  pain.  The  case  should  be  watched  closely  and  the  stim- 
ulating treatment  kept  up  until  the  part  has  healed.  The  tissue  in 
the  interproximal  space  will  never  be  fully  reproduced,  and  will  always 
be  a  source  of  more  or  less  annoyance. 

It  will  be  noted  that  in  discussing  the  treatment  of  local  arsenical 
poisoning,  no  mention  has  been  made  of  dialysed  iron.     The'prac- 


342         THE    ANESTHETIZATION    AND   DEVITALIZATION    OF   PULPS. 

tice  of  applying  this  agent  to  the  affected  part  is  both  useless  and 
wrong. 

In  closing  this  chapter  the  author  desires  to  emphasize  what  was 
stated  in  the  beginning,  that  it  is  the  plain  duty  of  every  practitioner 
to  study  the  pathology  of  the  pulp,  thus  learning  to  read  the  clinical 
symptoms  and  to  save  the  pulps  of  teeth  in  all  cases  where  it  can  be  done 
with  any  reasonable  degree  of  success;  yet  experience  and  observation 
will  soon  show  the  folly  of  attempting  to  save  a  pulp  that  has  been  irri- 
tated for  any  great  length  of  time,  and  will  prove  also  that  in  these  cases, 
the  safest  practice  is  to  remove  the  pulp  and  subsequently  fill  the  canal, 
notwithstanding  the  difficulty  often  attending  the  performance  of  this 
operation. 


CHAPTER  XX. 
THE  TREATMENT  OF  ORDINARY  PERICEMENTITIS. 

BY  J.  P.  BUCKLEY,  PH.  G.,  D.  D.  S. 

General  Considerations. — It  is  not  the  intention  to  introduce  in 
these  chapters  needless  pathologic  facts,  yet  in  the  treatment  of 
pericementitis  it  is  important  to  remember  that  the  pericemental 
membrane  is  very  vascular  and  well  supplied  with  nerves;  that  it  is 
enclosed  within  bony  walls,  and,  therefore,  when  inflammation  exists 
in  the  tissue  the  membrane  becomes  thickened,  forcing  the  tooth 
from  its  socket.  This  elongation  of  the  affected  tooth  is  one  of  the 
chief  symptoms  of  true  pericementitis. 

Before  discussing  the  therapeutics  of  pericementitis,  I  desire  to 
indelibly  impress  upon  the  mind  of  the  reader  the  fact  that  this  con- 
dition is  too  frequently  produced  by  carelessness  on  the  part  of  dentists. 
It  is  not  always  possible  to  successfully  perform  dental  operations 
without  irritating  the  susceptible  pericemental  membrane;  however, 
much  of  the  trouble  can  be  avoided  if  judgment  is  exercised  and  proper 
precautions  are  taken  in  treating  teeth. 

There  are  at  least  two  classes  of  irritants  by  which  ordinary  peri- 
cementitis is  produced,  viz.: 
(i)   Drug  irritants. 
(2)   Mechanical  irritants. 

The  inflammation  of  the  pericemental  membrane  caused  from 
drug  or  mechanical  irritants,  will  be  called  ordinary  pericementitis 
in  this  chapter,  in  order  to  differentiate  it  from  septic  pericementitis 
— a  condition  produced  by  pathogenic  bacteria,  poisonous  ptomains, 
and  irritating  gases,  which  have  escaped  from  a  putrescent  root  canal. 

Drug  Irritants. — There  are  many  circumstances  and  conditions 
which  influence  the  action  of  drugs  upon  different  individuals 
and  upon  the  same  individual  under  different  conditions.  We  find 
cases  occasionally  where  pulps  have  been  removed  by  pressure  anes- 
thesia, and  where,  seemingly  at  least,  every  precaution  was  taken  in 
sterilizing  the  dentin,  selecting  a  sterile  anesthetizing  solution  and  in 
applying  the  pressure;  yet  severe  apical  pericementitis  follows.  This 
may  or  may  not  be  due  to  the  drugs  used  in  performing  the  operation. 
There   are  cases,  too,  where  the  pericemental   membrane  becomes 

343 


344  THE    TREATMENT    OF    ORDINARY*  PERICEMENTITIS. 

highly  inflamed  and  extremely  responsive  from  the  action  of  arsenic 
trioxid,  even  when  the  drug  was  properly  scaled  within  the  tooth  only 
a  short  time.  These  are  conditions  over  which  the  operator  seems  to 
have  no  control;  however,  drugs  are  often  used  injudiciously.  In  the 
preceding  chapter  it  was  stated  that  an  anodyne  treatment  was  in- 
dicated after  the  mechanical  or  surgical  removal  of  the  pulp.  There- 
fore, care  should  be  taken  to  select  drugs  for  this  purpose  which  produce 
a  soothing  and  not  an  irritating  effect.  There  are  some  instances 
in  dental  practice  where  we  desire  to  irritate  and  thereby  stimulate  the 
pericemental  membrane;  but  this  should  be  avoided  here.  Judgment 
should  also  be  exercised  in  sealing  in  anodyne  remedies,  such  as  phenol, 
oil  of  cloves,  etc.,  in  the  canals,  especially  in  bicuspid  and  molar  teeth, 
for  should  the  temporary  filling  be  left  too  full  and  the  remedy  forced 
through  the  apex  by  the  closing  of  the  jaws,  even  these  agents  cease  to  be 
anodynes  and  become  irritants.  Whether  phenol,  oil  of  cloves,  and 
similar  drugs  or  remedies  are  anodynes  or  irritants,  depends  largely, 
then,  on  where  and  how  they  are  used. 

In  filling  root  canals  it  is  the  practice  of  many  dentists — the  author 
among  the  number — to  moisten  the  canals  with  eucalyptol  before  in- 
troducing chloro-percha  and  the  gutta-percha  cone.  Care  must  be 
taken  here  to  use  eucalyptol  and  not  oil  of  eucalyptus,  unless 
it  be  the  refined  product.  Commercial  oil  of  eucalyptus  has  been 
the  cause  of  many  cases  of  apical  pericementitis  following  the 
most  careful  filling  of  root  canals.  The  eucalyptus  tree  produces  a 
volatile  oil  which  contains  three  constituents,  each  distilling  over  at 
different  temperatures;  the  first  product  thus  obtained  is  eucalyptol, 
hence  the  most  volatile  constituent  of  oil  of  eucalyptus  and  the  one 
which  is  the  solvent  for  gutta-percha.  While  eucalyptol  is  a  slight 
irritant,  it  is  not  nearly  so  irritating  as  oil  of  eucalyptus.  The  irritat- 
ing property  of  eucalyptol  can  be  modified  and  its  antiseptic  value  in- 
creased by  adding  menthol  and  thymol  in  the  following  proportion: 

I^ — Mentholis,  gr.  ij 

Thymolis,  gr.  iij 

Eucalyptolis,  f.o  j     — M. 

Sig. — Use  as  directed. 

This  remedy  is  equally  as  good  a  solvent  for  gutta-percha  as  is  euca- 
lyptol alone;  and  will  be  called  eucalyptol  compound  in  the  following 
chapters. 

Mechanical  Irritants. — The  pericemental  membrane  is  frequently, 
I  might  add  too  frequently,  irritated  by  mechanical  irritants,  such  as 
root  canal  fillings,  ill-fitting  partial  plates,  crowns  and  bridges,  mallet- 


GENERAL    CONSIDERATIONS.  345 

ing,  regulating,  faulty  occlusion,  salivary  and  serumal  calculus,  etc. 
There  is  perhaps  more  pericementitis  produced  by  root  canal  fillings 
than  by  any  other  mechanical  irritant.  In  filling  root  canals  we 
should  be  absolutely  certain  that  the  canal  is  aseptic.  If  there  be  any 
doubt  as  to  this,  the  operation  should  be  deferred.  In  a  subsequent 
chapter  the  author  will  discuss  in  detail  the  technique  of  filling  root  canals; 
however  it  is  well  to  mention  here  that  care  should  be  taken  in  filling 
all  large  canals  so  that  the  filling  material  may  not  be  forced  through 
the  apex  of  the  root;  especially  should  we  be  careful  in  filling  the  canals 
of  teeth  after  having  treated  an  alveolar  abscess.  In  these  cases  we 
must  not  expect  the  patient  to  flinch  in  filling  the  root,  for  there  is  no 
live  tissue  at  the  immediate  end.  The  apex  has  been  enlarged  and  it 
is  very  easy  to  force  the  filling  material  through  into  the  space  where  the 
tissue  has  been  destroyed.  When  granulation  fills  this  space  and  the 
newly  formed  tissue  comes  in  contact  with  the  foreign  material,  the 
result  will  be  a  "lame  tooth,"  which  means  pericemental  trouble. 

A  frequent  cause  of  pericementitis  is  the  presence  of  microorgan- 
isms, which  have  been  introduced  through  the  failure  to  establish  and 
maintain  sepsis  in  removing  the  pulp  tissue;  or  pathogenic  bacteria, 
poisonous  ptomains  and  irritating  gases  that  have  escaped  into  the 
apical  area  from  a  putrescent  root  canal.  This  particular  kind  of 
pericementitis  is  known  as  septic  pericementitis,  and  is  closely  associated 
with  incipient  abscess.  The  nature  of  the  irritants  and  the  treatment 
of  the  condition  will  be  fully  considered  in  a  subsequent  chapter. 

Therapeutics. — The  first  step  in  the  treatment  of  ordinary  peri- 
cementitis is  to  adopt  the  surgical  principle  of  ascertaining  the  cause 
and  removing  or  correcting  it,  if  at  all  possible.  In  the  earlier  stages 
of  pericemental  inflammation,  it  is  not  always  an  easy  matter  to  ascer- 
tain the  true  cause  of  the  disturbance.  For  instance,  in  those  cases 
following  the  removal  of  the  pulp  tissue,  it  is  difficult  to  know  whether 
the  cause  is  the  root  filling,  the  medicine  used  in  the  treatment,  or 
whether  we  failed  to  establish  and  maintain  asepsis  in  performing  the 
operation.  The  author  is  inclined  to  believe  that  it  is  more  frequently 
the  latter  than  most  operators  are  willing  to  admit;  for  certain  it  is 
that  the  more  nearly  we  approach  absolute  asepsis  in  these  operations, 
the  less  pericemental  trouble  we  will  have.  The  teeth  thus  affected 
are  extremely  sore,  and  any  remedy  can  be  used  in  the  treatment  that 
will  give  immediate  relief.  This  is  what  the  patient  most  desires, 
and,  too  often  it  appears,  it  is  that  which  the  dentist  fails  to  give.  Both 
local  and  general  remedies  can  be  employed.  General  remedies  are 
more  valuable  in  the  treatment  of  septic  pericementitis.     If  they  are 


346  THE    TREATMENT    OF    ORDINARY    PERICEMENTITIS. 

used  at  all  in  treating  ordinary  pericementitis,  they  should  be  used  only 
in  cases  where  the  patient  is  nervous  and  has  lost  considerable  sleep. 
For  immediate  relief  we  must  depend  largely  upon  the  local  applica- 
tion of  drugs  and  remedies.  In  those  cases  following  the  removal  of 
the  pulp  by  either  the  anesthetization  or  devitalization  method,  and 
where  the  canals  have  not  been  filled,  the  pain  can  be  relieved  almost 
instantly  by  the  following  method:  Adjust  the  rubber  dam.  If  it 
is  necessary  to  use  a  clamp,  it  should  be  placed  on  the  tooth  posterior 
to  the  one  affected.  Sterilize  the  teeth  included  in  the  dam  and  re- 
move the  dressing  from  the  canals.  Dehydrate  the  tooth  structure 
with  absolute  alcohol.  Then  wrap  cotton  loosely  around  a  smooth, 
sterile  broach,  dip  in  oil  of  cloves  or  eugenol,  and  carefully  work  in  each 
canal.  Remove  the  broach,  leaving  the  cotton.  Heat  should  now 
be  applied  to  the  remedy  by  means  of  a  hot  air  instrument  or  a  chip- 
blower  until  the  cotton  becomes  dry.  Repeat  this  process  several 
times,  after  which  the  same  remedy  should  be  carefully  sealed  within 
the  canal.  In  doing  this,  we  not  only  get  the  benefit  of  the  heat,  which 
is  valuable;  but  the  eugenol,  the  constituent  of  cloves,  is  driven  into 
the  tooth  structure,  producing  a  profound  anodyne  effect  upon  the 
sensitive  membrane.  The  author  has  succeeded  in  giving  immediate 
relief  by  this  method  of  treatment  when  many  others  have  failed. 
Grinding  the  cusps  of  the  tooth  where  it  can  be  done  without  injury  is 
advisable;  a  counterirritant  can  be  applied  to  the  gum  and  the  patient 
dismissed  for  several  days.  It  is  scarcely  necessary  to  instruct  the 
patient  to  favor  the  tooth. 

In  the  treatment  of  pericementitis  following  the  filling  of  the  root, 
having  every  reason  for  believing  that  the  canals  were  aseptic,  one  of 
the  last  things  the  author  would  suggest  doing  would  be  to  attempt  to 
remove  the  root  filling.  Usually  this  only  serves  to  further  aggravate 
the  condition.  These  cases  can  best  be  treated  by  counterirritation 
and  general  remedies.  By  counterirritation  is  meant  the  application  of 
an  irritant  to  some  normal  part  of  the  body  for  the  purpose  of  influenc- 
ing favorably  some  other  part,  usually  deep-seated,  which  is  diseased. 
This  irritant  is  generally  applied  to  the  gum  over  the  affected  tooth. 
Capsicum  plasters,  black  mustard  papers,  cantharidal  collodion,  all 
official  preparations,  are  valuable;  or  the  following  liniments,  which  are 
more  generally  used,  give  much  relief: 

I^ — Menthol  is,  gr.    xx 

Chloroformi,  f.  3  j 

Tin cturae  aeon iti,  q.  s  ad,        f .  5  j     — M. 
— Dry  the  gum  and  apply  freely  over  the  af- 
fected tooth  for  several  minutes. 


GENERAL    CONSIDERATIONS.  347 

E^ — Tincturae  aconiti,  f.  5  ij 

Tincturae  iodi, 

Chloroformi,  aa  f .  3  j     ■    M. 

Sig. — Make  one -application  to  the  gum  as  above. 

I^ — Liquoris  iodi  compositae,  f.  5  j 

Sig. — Use  as  above. 

Inasmuch  as  tincture  of  aconite  is  an  important  ingredient  in  many 
liniments  used  in  the  local  treatment  of  pericementitis  and  facial  neu- 
ralgia, it  is  well  to  remember  that  the  United  States  Pharmacopeia  of 
1900  reduced  the  strength  of  this  preparation  from  35  per  cent  to  10 
per  cent.  Therefore  the  new  tincture  can  be  employed  more  freely  in 
these  cases  without  danger  of  poisoning. 

As  a  remedy  to  be  applied  by  the  patient  at  home,  a  split  raisin, 
soaked  in  hot  water,  and  on  which  is  dusted  red  pepper,  can  be  held  on 
the  gum  over  the  affected  tooth.  A  very  efficacious  remedy  is  to  di- 
rect hot  water  with  some  force  on  the  part,  beginning  with  warm  water 
and  increasing  the  heat  gradually  until  it  is  nearly  boiling.  This  must 
be  kept  up  until  we  get  the  full  benefit  of  the  heat  and  resolution  pro- 
moted. Another  good  remedy  to  have  the  patient  employ,  is  the  hot 
foot  bath.  The  value  of  this  remedy,  like  the  application  of  hot  water 
to  the  gums,  depends  largely  upon  the  manner  in  which  it  is  done.  A 
deep  foot-bath  tub  should  be  used  and  the  temperature  of  the  water 
gradually  increased  until  it  is  as  hot  as  can  be  borne.  This  should 
be  continued  from  twenty  to  thirty  minutes.  Frequently  the  pain  can 
be  relieved  by  spraying  with  ethyl  chlorid  the  area  over  the  offending 
tooth. 

There  are  many  other  drugs  and  remedies  which  can  be  employed 
in  the  local  treatment  of  this  condition.  Those  which  have  been  men- 
tioned here  the  author  has  found  valuable  in  his  practice.  It  is  far 
better  to  have  a  practical  knowledge  of  a  few  remedies  than  a  super- 
ficial knowledge  of  many.  The  general  remedies  to  be  administered 
in  the  treatment  of  ordinary  pericementitis,  if  found  necessary,  will  be 
discussed  under  the  treatment  of  septic  pericementitis  and  incipient 
abscess  in  a  subsequent  chapter. 


CHAFTER   XXI. 
THE  CHEMISTRY  OF  PULP  DECOMPOSITION. 

BY   J.    P.    BUCKLEY,    PH.G.,  D.  D.  S. 

General  Considerations. — The  subject  of  pulp  decomposition  is 
one  that  has  commanded  the  attention  of  many  investigators  in  our  pro- 
fession, and  at  the  present  time  the  conclusions  as  to  the  chemistry  of 
the  process  are  by  no  means  uniform.  While  this  fact  is  to  be  regretted, 
it  must  be  remembered  here  that  there  are  many  difficulties  presenting 
themselves  to  the  student  who  attempts  to  study  this  complicated  proc- 
ess from  the  chemical  viewpoint,  either  for  the  purpose  of  outlining  a 
rational  treatment  for  the  correction  of  the  putrescent  condition,  or  for 
the  purpose  of  solving  the  knotty  problems  of  the  discoloration  of  tooth 
structure  from  this  source.  Until  we  comprehend  more  fully  the  nature 
of  the  chemical  reactions  taking  place  in  the  splitting  up  of  the  com- 
plex bodies  of  dead  pulp  tissue  and  have  a  more  definite  knowledge 
of  the  intermediate  and  end-products  thus  produced,  the  application 
of  drugs  and  remedies  for  the  correction  of  the  putrescent  condition 
and  for  the  restoration  of  the  color  of  the  tooth  structure  can  never  be 
placed  upon  a  rational  basis,  but  must  be  empirical,  as  it  has  been  in 
the  past.  This  is  not  in  accordance  with  the  tendency  of  the  present 
time.  There  is  a  strenuous  effort  being  made  in  both  medicine  and 
dentistry,  to  rid  the  professions  of  much  of  the  empiricism  of  the  past 
and  to  place  the  treatment  of  all  diseased  conditions  upon  a  rational 
basis.  With  this  end  in  view  the  author  desires  in  this  chapter  to 
direct  the  reader's  attention  to  the  chemistry  of  pulp  decomposition. 

It  is  essential .  in  studying  the  chemistry  of  this  process  to  first  as- 
certain the  chemical  constituents  of  the  original  pulp  tissue.  So  far  as 
chemists  have  been  able  to  determine,  practically  all  of  the  elements 
are  present  in  the  pulp  tissue  and  its  vascular  supply  that  are  found  in 
any  other  animal  tissue.  These  elements  are  arranged  in  different 
compounds  which  make  up  the  pulp  tissue,  the  proportion  of  which 
varies  from  other  tissues,  and  this,  no  doubt,  accounts  for  the  histologic 
difference  between  this  and  many  of  the  other  tissues  of  the  body. 
However,  from  a  general  chemical  examination  of  the  pulp  tissue  we 
find  it  analogous,  or  nearly  so,  to  all  other  animal  tissue.     This  suggests 

349 


350  THE    CHEMISTRY    OF    PULP    DECOMPOSITION. 

at  once  the  necessity  for  the  student's  familiarity  with  the  general 
composition  of  animal  tissue,  which  will  now  be  considered. 

Chemical  Composition  of  Animal  Tissue. — There  are  at  the  present 
time  about  seventy-six  elements  known  to  chemistry;  but  of  this  num- 
ber less  than  seventeen  unite,  in  varying  proportions,  to  form  the  chem- 
ical basis  of  the  animal  body.  In  fact,  six  elements  are  about  all 
with  which  we  are  concerned  in  the  study  of  the  decomposition  of  the 
pulp  tissue.  These  elements  are  carbon,  C;  hydrogen,  H;  oxygen,  O; 
nitrogen,  N;  sulphur,  S;  and  iron,  Fe. 

For  convenience  in  study,  the  various  substances  found  in  animal 
tissue  arc  divided  into  two  general  classes,  the  classification  being  based 
upon  the  presence  or  absence  of  the  element  nitrogen,  and  are  accord- 
ingly called  nitrogenous  and  non-nitrogenous  substances. 

Nitrogenous  Substances. — We  are  taught  by  physiologists  that 
nitrogenous  organic  bodies  take  the  chief  part  in  forming  the  solid 
tissues,  and  to  an  extent  are  also  found  in  the  fluids  of  the  body.  Pro- 
teid,  or  albuminous,  substances  are  the  principal  nitrogenous  com- 
pounds, and  one  or  more  enter  as  an  essential  part  into  the  formation 
of  all  living  tissue.  The  elements  which  constitute  the  proteid  molar 
cule  are  carbon,  hydrogen,  oxygen,  nitrogen  and  a  small  amount  of 
sulphur.  Iron  and  phosphorus  are  known  to  exist  in  the  molecule  of 
some  proteid  bodies.  While  some  chemists  have  attempted  to  con- 
struct a  formula  for  the  molecule,  none  has  been  accepted  as  correct, 
the  opinions  of  investigators  being  so  varied.  To  the  casual  observer 
it  may  seem  strange  that  a  molecule  consisting  largely,  as  it  does,  of 
carbon,  hydrogen,  oxygen  and  nitrogen,  should  have  these  four  simple 
elements  so  arranged  as  to  bafHe  chemists  in  their  effort  to  construct  a 
rational  formula.  But  this  difficulty  is  readily  explained  by  the  fact 
that  of  all  the  elements  none  differ  more  widely  from  each  other  in 
their  physical  and  chemical  properties  than  these  four.  Carbon  is  a 
solid  substance  which  exists  in  nature  in  three  forms:  Charcoal, 
graphite,  and  diamond,  and  can  scarcely  be  fused  or  volatilized.  Hy- 
drogen, oxygen,  and  nitrogen  are  colorless  gases  which  cannot  be 
solidified  by  any  known  means  and  can  be  converted  into  liquids  only 
with  difficulty.  The  three  gases  also  differ  in  their  chemical  activity. 
Hydrogen  is  combustible;  oxygen  will  not  burn,  but  will  support  com- 
bustion; while  nitrogen  is  perfectly  indifferent.  Fortunately,  too,  for 
nature,  in  her  effort  to  arrange  these  elements  into  a  complex  molecule, 
the  valency  of  each  differs.  Hydrogen  is  univalent,  oxygen  bivalent, 
nitrogen  trivalent,  and  carbon  quadrivalent,  generally  considered. 
Carbon  atoms  have  also,  to  a  higher  degree  than  the  atoms  of  any  other 


GENERAL    CONSIDERATIONS.  35 1 

element,  the  power  of  combining  with  each  other  by  means  of  a  portion 
of  the  affinity  possessed  by  each  atom,  thereby  increasing  the  possibil- 
ities of  the  formation  of  complex  compounds.  Thus  many  atoms  of 
the  same  element  occur  in  each  molecule,  which,  together  with  the  fact 
that  one  of  the  elements  is  that  peculiar,  undecided  and  indifferent 
element,  nitrogen,  aids  materially  in  explaining  the  reason  for  the  insta- 
bility of  the  proteid  molecule,  or  the  ease  with  which  under  certain 
conditions  it  is  decomposed. 

In  order  that  the  reader  may  be  able  to  follow  a  theory  which  the 
author  will  advance  in  a  subsequent  chapter  on  the  discoloration  prob- 
lem, it  is  well  to  remember  here  that  the  relative  amount  of  nitrogen 
compared  with  sulphur  found  in  the  proteid  molecule  is  15  per  cent  of 
the  former  to  0.3  per  cent  of  the  latter. 

Non-nitrogenous  Substances. — The  non-nitrogenous  substances  con- 
sist of  carbohydrates  and  jats.  Several  classes  of  carbohydrates  are 
known  to  exist,  all  of  which  are  much  less  complex  than  the  proteid 
group;  and  the  arrangement  of  the  atoms  in  the  molecule  is  much  better 
imderstood.  The  carbohydrate  molecule  is  composed  of  three  ele- 
ments— carbon,  hydrogen  and  oxygen.  There  are  alw^ays  six  (or  a 
multiple  of  six)  atoms  of  carbon  in  the  molecule,  while  the  hydrogen 
and  oxygen  exist  in  the  proportion  to  form  water.  These  compounds 
readily  undergo  the  process  of  fermentation. 

Human  fats  are  principally  mixtures  of  palmitin,  C3Hs(Ci6H3iO)3- 
O3;  stearin,  C3H5(Ci8H,50),03;  and  a  small  amount  of  olein,  C3HS- 
(C,8H330)303.  As  shown  by  the  formula  of  these  compounds,  the 
molecules  of  each  also  consist  of  carbon,  hydrogen  and  oxygen.  The 
proportion  of  these  elements  varies  in  the  different  compounds.  That 
fats  are  decomposed  or  saponified  by  alkalies,  or  ferment  in  an  alkaline 
medium,  should  be  remembered,  both  in  the  treatment  and  the  bleach- 
ing of  teeth. 

Thus  we  have  every  reason  for  believing  that  the  pulp  tissue,  like 
nearly  all  living  organic  tissue,  is  composed  of  proteids,  carbohydrates, 
and  fats;  and  on  this  hypothesis  the  author  will  endeavor  to  ascertain 
the  intermediate  and  end-products  resulting  from  the  decomposition 
of  this  tissue  when  death  occurs.  Before  doing  so,  however,  it  may  be 
well  that  the  reader  fully  understand  what  is  meant  by  the  terms  fer- 
mentation and  putrefaction.  These  terms  are  applied  to  peculiar  kinds 
of  decomposition  by  which  the  molecules  of  certain  organic  substances 
are  broken  up  into  simpler  compounds.  The  difference  between  the 
terms  is  that  fermentation  is  applied  to  the  decomposition  of  those 
substances  which  belong  to  the  group  of  carbohydrates,  while  putre- 


352  THE    CHEMISTRY    OF    PULP    DECOMPOSITION. 

faction  is  applied  to  the  decomposition  of  those  substances  which  prop- 
erly belong  to  the  proteid  group  and  are  classified  as  nitrogenous 
substances. 

Pu^p  Decomposition. — The  decomposition  of  the  pulp  tissue  is 
essentially  an  analytic  process  which  takes  place  gradually.  Con- 
ditions being  favorable,  the  germs  present  first  act  upon  the  complex 
and  unstable  substances  composing  the  original  tissue,  splitting  them 
up  into  less  complex  compounds,  many  of  which  are  capable  of  further 
analysis;  and  the  process  goes  on  until  simple  and  well-known  com- 
pounds are  the  result.  For  convenience  in  studying  this  subject  the 
compounds  resulting  from  this  analytic  process  will  be  arbitrarily 
divided  into  two  classes,  intermediate  and  end-products;  and  it  will  be 
seen  that  it  is  largely  the  products  of  putrefaction  rather  than  of  fer- 
mentation with  which  we  have  to  contend  in  the  correction  of  the 
putrescent  condition. 

Intermediate  Products. — The  intermediate  products  depend  to  an 
extent  upon  the  character  of  the  microorganisms  in  the  tissue,  but  it  is 
safe  to  say  that  certain  ptomains  and  amido-acids  are  formed. 

(i)  Ptomains. — Ptomains  are  nitrogenous  compounds  of  organic 
origin,  having  the  reaction  and  basic  property  of  alkalies.  By  some 
authorities  they  are  called  animal  alkaloids,  to  distinguish  them  from  a 
similar  group  of  organic  bases  known  as  vegetable  alkaloids. 

Among  the  ptomains  liable  to  be  produced  are  putrescin,  C4H,^Nj, 
cadaverin  and  neuridin,  C^Hj^N^,  the  last  two  named  being  isomeric 
as  shown  by  the  formula.  One  of  these  ptomains,  neuridin,  is  non- 
poisonous;  therefore  its  presence  is  of  little  importance  other  than  to 
know  that  it  is  a  nitrogenous  base  from  which  ammonia,  NH3,  or 
derivations  of  ammonia,  is  evolved  by  further  putrefaction.  Still, 
according  to  Vaughan  and  Novy,  while  pure  neuridin  is  non-poison- 
ous, it  possesses  a  toxic  property  as  long  as  it  is  contaminated  with 
other  poisonous  products  of  putrefaction.  This  holds  true  for  all  non- 
poisonous  bases.  In  so  far  as  the  correction  of  the  putrescent  condition 
is  concerned,  putrescin  and  cadaverin  are  perhaps  the  most  important 
intermediate  products  known  to  be  formed  in  the  splitting  up  of  the 
proteid  molecule.  Like  neuridin,  they  are  basic  nitrogenous  com- 
pounds, capable  of  undergoing  further  putrefaction,  evolving  ammonia 
or  derivatives;  but  unlike  this  compound,  while  they  were  at  first  re- 
garded as  physiologically  inactive,  both  of  these  bases  have  been  proved 
by  Scheurlen,  Grawitz  and  others  to  be  capable  of  producing  inflamma- 
tion and   suppuration.     Therefore   if  by  instrumentation   or  other- 


GENERAL    CONSIDERATIONS.  353 

wise  they  are  forced  through  the  apices  of  the  roots,  septic  pericemen- 
titis or  perhaps  an  acute  alveolar  abscess  will  result. 

(2)  Amido-acids. — Amido-acids  are  acids  in  which  hydrogen  has 
been  replaced  by  the  univalent  radical,  NH^.  Among  the  amido- 
acids  formed  in  pulp  decomposition,  in  all  probability,  are  tyrosin, 
C6H40HC,H3(NHJCO,H,  and  leucin,  CsH.oNH.CO.H.  These 
substances,  wherever  found,  have  practically  the  same  physiologic 
properties  and  pathologic  significance.  They  occur  in  the  intestine 
during  the  digestion  of  proteids,  and  leucin  is  found  in  almost  every 
cell  of  the  animal  body.*  Pathologically,  they  are  found  in  ather- 
omatous cysts,  in  pus,  abscesses,  etc.,  as  well  as  in  a  putrescent  root 
canal.  It  is  well  to  remember  here  that  these  intermediate  products 
are  also  nitrogenous  compounds  from  which  ammonia,  or  derivatives 
of  ammonia,  is  evolved  by  further  putrefaction,  and  that  jats  are  one  of 
the  end-products. 

End-products. — The  chief  end-products  of  pulp  decomposition, 
as  has  been  known  for  a  long  time,  are  water,  H^O;  carbon  dioxid, 
COj;  acetic  acid,  HC^H^O^;  ammonia,  NH3;  hydrogen  sulphid, 
H^S;  and  a  semi-putrid  substance  consisting  largely  of  fats,  depending 
upon  the  extent  to  which  the  putrefactive  process  has  progressed. 

Simultaneously  with  the  decomposition  of  the  pulp  tissue  proper, 
the  dentinal  fibrillse  are  broken  up,  as  is  also  the  hemoglobin  and  other 
constituents  of  the  blood;  and  the  tubuli  as  well  as  the  pulp  chamber 
and  root  canals  are  filled  with  the  intermediate  and  end-products 
of  the  decomposition. 

The  principal  gases  generated  by  the  putrefaction  of  the  proteid 
substances,  the  main  constituent  of  the  original  pulp  tissue,  are  ammo- 
nia and  hydrogen  sulphid.  Now,  it  is  interesting  and  important  to 
know  which  of  these  two  gases  is  evolved  in  the  greater  quantity.  This 
is  easily  estimated  when  we  recall  the  relative  amount  of  nitrogen  and 
sulphur  found  in  the  proteid  molecule.  As  previously  stated,  there  is 
approximately  15  per  cent  of  the  nitrogen  to  0.3  per  cent  of  sulphur. 
Hence,  ammonia  is  evolved  in  the  greater  quantity.  It  is  quite  evident, 
then,  that  hydrogen  sulphid  is  not  generated  in  a  putrescent  root  canal 
in  such  quantities  as  has  been  so  generally  supposed;  yet  this  com- 
pound is  a  constant  end-product  and  is  important,  because  it  is  an  acid 
gas,  with  a  disagreeable  odor,  having  local  irritating  properties;  and 
also  because  of  the  part  it  plays  in  the  discoloration  of  the  tooth  struc- 
ture. The  author  desires  to  state  here,  however,  that  while  he  realizes 
hydrogen  sulphid  is  an  active  chemical  agent,  in  his  opinion  it  has  been 

♦Simon's  "Manual  of  Chemistry." 
23 


354  THE    CHEMISTRY    OF    PULP    DECOMPOSITION 

greatly  over-estimated  in  the  r61e  it  assumes  in  the  discoloration  of  teeth 
from  pulp  decomposition  as  will  be  shown  in  a  subsequent  chaf)ter. 

In  our  study  thus  far  of  the  chemistry  of  the  complicated  process 
of  pulp  decomposition,  we  have  learned  something  of  the  nature  of 
the  intermediate  and  end-products  resulting  therefrom,  and  now  it  is 
possible  for  us  to  select,  with  some  intelligence,  drugs  and  remedies 
which  will  not  only  destroy  bacteria,  but  will  also  act  chemically  upon 
these  noxious  products,  converting  them  into  non-infectious  and  non- 
toxic compounds. 


CHAPTER  XXII. 

THE  TREATMENT  OF  PUTRESCENT  PULPS— ACUTE 
AND  CHRONIC  ALVEOLAR  ABSCESS,  WITH  COM- 
PLICATIONS; AND  THE  FILLING   OF 
ROOT  CANALS. 

BY   J.    P.    BUCKLEY,    PH.G.,  D.  D.  S. 

General  Considerations. — ^The  treatment  of  putrescent  pulps  and 
their  sequelae  in  the  past,  has,  to  a  great  extent,  been  purely  empirical. 
The  reason  for  this  can  be  found  in  the  apparent  lack  of  interest  which 
generally  has  been  shown  in  the  chemistry  of  pulp  decomposition.  A 
knowledge  of  the  changes  wrought  in  the  splitting  up  of  the  complex 
bodies  of  the  dental  pulp  by  microorganisms  is  of  vital  interest  to 
every  practicing  dentist;  and  every  student  should  therefore  familiar- 
ize himself  with  this  important  subject.  The  only  method  by  which 
drugs  and  remedies  can  be  scientifically  applied  to  the  treatment  of 
the  conditions  under  consideration  is  to  have  a  definite  knowledge 
of  the  intermediate  and  end-products  resulting  from  the  putrefactive 
process  as  outlined  in  the  preceding  chapter. 

Every  practitioner  of  dentistry  knew  from  sad,  past  experience 
that  in  the  process  of  pulp  decomposition,  some  kind  of  mephitic  gases 
were  evolved  W'hich  if  confined  would  produce  severe  pathologic 
disturbances;  but  just  what  the  gases  were  and  how  the  unfavorable 
conditions  were  brought  about  we  were  left  to  conjecture.  From  our 
study  of  the  chemistry  of  pulp  decomposition  we  have  every  reason 
for  believing  thai  the  main  gases  produced  are  ammonia  and  hydrogen 
sulphid.  When  these  gases  are  generated  and  cannot  readily  escape 
through  a  cavity,  pressure  is  produced,  thereby  forcing  microorganisms 
and  their  poisonous  ptomains  through  the  apices  of  the  roots  into  the 
surrounding  tissue  from  which  infection,  septic  pericementitis  and  in 
many  instances  an  alveolar  abscess  result. 

There  has  been  much  discussion  in  the  dental  literature  of  the  past 
in  regard  to  the  penetrating  or  non-penetrating  power  of  coagulating 
agents  in  putrescent  root  canals.  It  is  true,  as  claimed  by  some 
authorities,  that  such  drugs  as  phenol,  creosote,  solutions  of  zinc  chlorid, 
etc.,  are  contraindicated  in  the  treatment  of  putrescent  pulps,  but  not 

355 


356  THE  TREATMENT  OF  PUTRESCENT  PULPS. 

because  they  possess  the  coagulating  property;  for  when  the  dental 
pulp  is  undergoing  or  has  undergone  the  process  of  decomposition, 
the  proteid  constituents  or  coagulable  substances  have  lost  their  for 
raer  identity,  and  new  compounds  with  entirely  different  properties 
have  been  formed.  In  selecting  drugs  to  be  used  in  the  treatment  of 
this  condition,  the  author  will  therefore  eliminate  the  question  of  coag- 
ulation and  will  select  drugs,  which,  if  properly  used,  will  unite  chemic- 
ally with  the  intermediate  and  end-products  of  decomposition,  con- 
verting them  into  odorless  and  non-infectious  compounds,  as  well 
as  destroy  germ  life.  In  this  connection  it  should  be  remembered 
that  the  putrescent  condition  has  been  brought  about  through  the 
agency  of  microorganisms  by  a  gradual  analytic  process,  and  among 
the  products  formed  which  must  be  considered  in  the  treatment  are 
hydrogeji  sulphid,  the  poisonous  plomains  (putrescin  and  cadaverin), 
and  ammonia  or  derivatives,  the  latter  gas  being  evolved  from  the  further 
putrefaction  of  the  last  named  compounds,  or  compounds  of  similar 
composition.  It  is  well  to  remember  also  that  fats  or  fatty  acids  are 
a  class  of  end-products  resulting  from  the  putrefaction  of  proteid 
substances. 

The  main  gases  formed,  then,  are  ammonia  and  hydrogen  sulphid. 
Now  it  will  be  necessary  to  dispose  of  these  gases  in  order  to  hermetic- 
ally seal  the  cavity,  an  object  the  accomplishment  of  which  is  much 
desired  in  the  treatment  of  these  cases;  for  by  so  doing  we  prevent  the 
oral  fluids  from  contaminating  the  medicine  within  the  tooth,  the  med- 
icine from  escaping  into  the  patient's  mouth,  and  the  tooth  from 
changing  color  during  the  time  of  treatment. 

It  has  been  known  for  some  time  that  Jormaldehyd  (CHjO),  a  gas 
which  occurs  in  commerce  in  a  thirty-seven  per  cent  aqueous  solution 
and  which  solution  is  recognized  by  the  United  States  Pharmacopeia 
of  1900  under  the  name  of  liquor  formaldehyd,  or  formalin,  will 
unite  with  ammonia,  producing  urotropin,  a  solid,  as  6CH2O+4NH3 
=  (CH,)5N,+6H,0. 

Formaldehyd  unites  also  with  hydrogen  sulphid,  forming,  in  the 
author's  opinion,  methyl  alcohol,  a  liquid,  and  sulphur,  a  solid,  as 
2CH,0  +  2H  S  =  2CH30H-hS,. 

It  is  stated  on  good  authority  that  this  same  gas,  formaldehyd, 
unites  with  basic  ptomains,  forming  inodorous  compounds.  By  the 
use  of  formaldehyd,  then  the  irritating  gases  and  poisonous  liquids 
(largely  ptomains)  can  be  changed  chemically  into  non-irritating  and 
non-poisonous  liquids  and  solids.  The  official  solution  of  formaldehyd, 
however,  is  too  irritating  for  general  use;  therefore,  inasmuch  as  fats 


GENERAL  .  CONSIDERATIONS.  357 

result  from  pulp  decomposition  and  are  present  as  such  in  a  putres- 
cent root  canal,  the  author  selected  cresol  as  an  agent  with  which  to 
dilute  the  official  solution  and  thereby  modify  the  irritating  action  of 
formaldehyd.  Cresol  is  now  also  recognized  by  the  United  States 
Pharmacopeia  of  1900  under  this  name.  Formerly  the  product  was 
commercially  called  tricresol.  This  agent  has  a  tendency  to  darken 
when  exposed  to  light.  It  is  recommended  that  a  clear  solution  be 
obtained  and  then  kept  in  an  amber  colored  bottle. 

Liquor  formaldehyd  can  be  diluted  with  such  other  agents  as 
phenol,  or  creosote,  if,  in  the  latter  instance,  a  small  amount  of  alcohol 
is  added  to  clear  the  solution.  Cresol,  however,  is  recommended  for 
four  principal  reasons: 

1.  It  is  miscible  with  the  liquor  formaldehyd  in  all  proportions, 
thus  making,  without  the  addition  of  alcohol,  a  good  pharmacal  product 
from  which  formaldehyd  gas  is  constantly  generated. 

2.  It  is  a  good  disinfectant,  much  more  powerful  than  phenol. 

3.  It  possesses  an  anodyne  property  which  modifies  the  irritating 
action  of  formaldehyd. 

4.  It  acts  chemically  upon  the  fatty  compounds  thereby  disposing 
to  advantage  of  these  substances. 

Treatment. — In  the  successful  treatment  of  the  conditions  under 
consideration  there  are  three  important  factors  which  must  be  ac- 
complished : 

1.  Establish  asepsis. 

2.  Prevent  recurring  sepsis. 

3.  Preserve  or  restore  the  color  of  the  tooth. 

I.  Putrescent  Pulps. — In  calling  the  attention  of  the  reader  to  a 
method  of  treating  this  condition,  which  has  proved  very  successful 
in  the  author's  practice,  I  desire  to  emphasize  the  necessity  for  ob- 
serving the  details  of  the  method.  Our  first  duty  here,  as  in  all  treat- 
ment cases,  is  to  make  a  correct  diagnosis,  after  which  the  rubber 
dam  should  be  adjusted  in  every  case  where  it  is  possible  to  do  so, 
and  all  the  teeth  included,  sterilized.  For  this  purpose  either  a  ten 
per  cent  solution  of  formaldehyd  to  which  a  small  amount  of  borax 
has  been  added,  or  a  1-500  solution  of  mercury  bichlorid  in  cinnamon 
water  can  be  used.  After  using  one  of  these  solutions  the  teeth  are 
bathed  in  alcohol,  when,  with  a  suitable  round  bur,  the  pulp  chamber 
is  freely  opened,  exposing  all  of  the  canals,  but  making  no  attempt 
to  remove  the  contents  therein  at  this  sitting.  Now,  on  a  small 
pledget  of  cotton  the  following  remedy  is  placed  in  the  pulp  chamber 
and  over  the  mouth  of  each  canal. 


358  THE  TREATMENT  OF  PUTRESCENT  PULPS. 

Original  Formula. 

I^ — Cresolis, 

Liquoris  formaldehydi,  aa     f3j — M. 

Sig. — Use  as  directed. 

For  convenience  this  remedy  will  be  called  jormocresol.  It  is 
always  best  to  seal  the  cavity  with  a  quick-setting  cement,  for  the 
remedy  should  be  hermetically  sealed  and  pressure  must  he  avoided. 
To  prevent  the  cement  from  filling  the  entire  cavity  and  also  to  facili- 
tate its  subsequent  removal,  metallic  or  paper  discs  or  even  cotton  can 
be  placed  over  the  remedy,  filling  most  of  the  cavity,  when  only  a  veneer 
of  cement  is  necessary  to  hermetically  seal  it.  This  dressing  can  re- 
main until  you  wish  to  have  the  patient  return  for  a  subsequent  sitting. 
The  author  prefers  to  leave  it  about  two  or  three  days.  However,  it 
can  be  safely  changed  the  following  day,  and  no  harm  follow  if  it 
remains  a  week  or  more.  At  the  second  sitting,  the  rubber  dam 
should  be  adjusted,  the  teeth  included  sterilized,  and  the  dressing 
removed,  after  which  the  canals  should  be  mechanically  cleaned  with 
a  proper  broach,  exercising  the  same  judgment  here  in  the  selection 
of  the  broach  as  was  emphasized  in  a  previous  chapter.  If  there  be 
any  odor  in  the  canals  characteristic  of  putrescence,  or  if  effervescence 
is  produced  by  testing  with  a  solution  of  hydrogen  dioxid,  the  canals 
should  be  dehydrated  with  alcohol  and  warm  air  as  thoroughly  as 
possible  and  formocresol  again  placed  on  cotton,  this  time  loosely 
in  each  canal,  and  the  cavity  hermetically  sealed. 

In  those  cases,  where,  at  the  second  sitting,  there  is  no  evidence 
of  putrescence,  which  will  be  found  to  be  the  condition  generally  if 
the  first  treatment  is  properly  employed,  the  original  formula  can  be 
modified  and  used.  It  is  not  necessary  or  advisable,  however,  to 
keep  a  modified  formula  prepared.  It  can  readily  be  made  at  the 
time  by  taking  two  minims  of  the  original  formula  on  a  clean  watch 
crystal,  and  adding  to  this  one  or  two  minims  of  cresol  as  thought  best 
by  the  operator  at  the  time.  This  dressing  should  remain  for  at  least 
three  days,  by  which  time  the  remedy  will  have  sterilized  the  entire 
tubular  structure  of  the  dentin,  thus  establishing  asepsis.  All  that  is 
necessary  now  to  prevent  recurring  sepsis  is  to  thoroughly  fill  the  canals. 
This  remedy  will  not  discolor  tooth  structure  and  the  fact  that  it  not 
only  can  but  should  be  hermetically  sealed  in  the  cavity,  will  prevent 
discoloration  by  the  ingress  of  the  fluids  of  the  mouth.  In  case  the 
color  of  the  tooth  crown  was  lost  before  undertaking  the  treatment  and 
being  desirous  of  preserving  the  tooth  by  an  inlay  or  filling,  the  color 
can  be  restored  by  one  or  two  applications  of  sodium  dioxid,  NajO,. 


GENERAL    CONSIDERATIONS.  359 

or  by  sealing  a  25  per  cent  ethereal  solution  of  hydrogen  dioxid  (pyrozone) 
in  the  cavity  for  twenty-four  or  forty-eight  hours.  The  use  of  sodium 
dioxid  will  be  explained  in  a  subsequent  chapter  on  bleaching  teeth. 

Complications. — i.  Badly  Decayed  Root. — This  formocresol  is 
very  destructive  to  the  soft  tissues  of  the  mouth,  therefore  the  im- 
protance  of  always  adjusting  the  rubber  dam.  If  this  cannot  be  done 
on  account  of  a  badly  decayed  root,  it  is  suggested  that  care  be  taken 
in  seahng  the  remedy  in  the  cavity  at  the  first  sitting,  and,  in  placing 
the  cement,  the  original  outline  of  the  root  can  be  approximated. 
After  the  cement  has  set,  a  band  or  matrix  of  gold  or  German  silver 
can  be  fitted  to  and  cemented  on  the  root.  In  treating  the  case  where 
there  is  a  tooth  posterior,  it  is  best  to  place  the  clamp  on  this  tooth 
and  gently  stretch  the  rubber  over  the  band  and  thereby  avoid 
loosening  it. 

2.  Pulp  Partially  Alive. — In  those  cases  where  the  pulp  tissue 
is  putrescent  in  one  or  more  canals  of  a  multirooted  tooth  and  alive 
in  the  other  one  or  two  canals,  as  the  case  may  be,  we  will  find  much 
satisfaction  in  using  the  formocresol  remedy.  These  are  exceptional 
cases  and  it  is  difficult  to  know  whether  this  condition  exists  until  the 
second  sitting.  If  there  be  much  vitality  in  the  live  pulp  tissue,  the 
formaldehyd  in  the  remedy  will  doubtless  make  the  tooth  ache,  but 
after  we  know  the  conditions  our  method  of  procedure  is  simple  and 
the  results  will  be  certain.  A  small  pledget  of  cotton  dipped  in  the 
remedy  can  be  gently  placed  over  the  mouth  of  the  canals  which  con- 
tain putrescent  material,  and  a  thin  quick-setting  cement  flowed  over 
the  cotton.  After  the  cement  has  set  the  live  pulp  tissue  in  the  remain- 
ing canals  can  be  anesthetized  or  devitalized  as  the  operator  deems  best 
at  the  time.  Formerly  these  were  difficult  cases  to  treat,  but  with  a 
remedy  which  can  be  hermetically  sealed  in  a  putrescent  root  canal, 
the  procedure  is  materially  simplified. 

The  author  realizes  that  the  method  of  treating  putrescent  pulps, 
here  given,  is  a  radical  departure  from  those  generally  advocated ;  and, 
like  myself  at  first,  some  of  my  experienced  readers  may  hesitate  to 
hermetically  seal  a  cavity  in  a  tooth  which  contains  a  putrescent  pulp. 
The  reason  this  could  not  be  done  in  the  past  by  the  methods  in  vogue, 
is  that  drugs,  in  most  instances,  were  selected  and  used  solely  because 
of  their  ability  to  inhibit  the  growth  or  destroy  the  vitality  of  micro- 
organisms. The  fact  that  there  were  other  things,  such  as  irritating 
gases,  and  poisonous  ptomains,  found  in  the  canal  and  tubular  structure 
of  the  dentin,  and  also  the  further  fact  that  it  was  as  necessary  to  dispose 
of  these  substances  as  it  was  to  destroy  germ  life,  was  not  given  the 


360  THE  TREATMENT  OF  PUTRESCENT  PULPS. 

significance  this  phase  of  the  subject  merited.  The  treatment  which 
is  here  outlined  is  along  rational  lines,  for  the  remedy  chemically 
converts  the  noxious  intermediate  and  end-products  of  pulp  decom- 
position into  substances  which  themselves  possess  antiseptic  and  dis- 
infectant properties. 

II.  Acute  Alveolar  Abscess. — The  treatment  of  septic  perice- 
mentitis and  acute  alveolar  abscess,  as  was  intimated  in  the  chapter 
on  The  Treatment  of  Pericementitis,  is  so  nearly  identical  that 
they  will  be  discussed  here  conjointly.  In  those  cases  where  the 
patient  did  not  present  for  treatment  until  the  confined  gases  had 
escaped  through  the  end  of  the  root,  carrying  the  microorganisms  and 
poisonous  ptomains  into  the  surrounding  tissue,  it  is  our  duty  to  try 
to  aid  nature  in  aborting  an  abscess.  It  is  in  these  cases  that  good  ji^dg- 
ment  must  be  exercised,  and  extreme  care  taken.  There  is  no  condition 
which  we  are  called  upon  to  treat  wherein  a  practical  knowledge  of  path- 
ology and  therapeutics  will  serve  us  better  than  in  this  particular  case. 
Frequently  patients  delay  coming  to  the  dentist  until  the  infection  has 
progressed  to  a  point  where  all  remedies  will  fail  in  aborting  an  abscess ; 
but  in  many  instances  this  result  may  be  prevented  by  the  proper 
use  of  drugs.  The  local  treatment  here  is  exactly  the  same  as  above 
for  an  ordinary  putrescent  pulp;  for  you  never  have  a  case  of  septic 
pericementitis  or  incipient  abscess  unless  the  pulp  is  dead  and  has 
undergone,  partially  at  least,  the  process  of  decomposition.  How- 
ever, if  the  tooth  is  extremely  sore,  as  is  usually  the  case,  the  patient 
need  not  be  subjected  at  this  sitting  to  the  annoyance  of  adjusting  the 
rubber  dam.  Keep  the  tooth  just  as  dry  as  possible,  open  into  the 
pulp  chamber,  holding  the  tooth  by  some  means  while  drilling,  so 
that  the  jarring  will  not  further  irritate  the  condition;  then  carefully 
seal  in  the  formocresol  remedy  with  cement;  after  which  our  attention, 
if  necessary,  should  be  given  to  the  treatment  of  the  infected  peri- 
cemental membrane.  In  order  to  control  the  infection,  and  at  the 
same  time  aid  nature  in  readjusting  the  abnormal  condition,  it  is  not 
only  our  privilege,  but  it  is  our  duty  in  these  severe  cases  to  administer 
internal  drugs.  Here  alterative  drugs  are  indicated.  The  great  rep- 
resentative of  the  alterative  class  is  potassium  iodid,  which  can  be 
given  in  the  following  prescription: 

I^ — Potassii  iodidi,  3  jss 

Syrupi  sarsaparillse  comp.,  f5  iij — M. 

Sig. — Take  a  teaspoonful  in  water  after  meals. 

Ordinarily  the  directions  would  be  as  given,  to  have  the  patient 
take  a  teaspoonful  three  times  a  day  after  meals;  but  in  these  cases  of 


GENERAL    CONSIDERATIONS.  36 1 

septic  pericementitis  or  incipient  abscess  it  is  best  to  direct  the  patient 
to  take  a  teaspoonful  every  two  hours  until  three  or  four  doses  are 
taken,  and  then  follow  the  directions  written  on  the  label.  It  is  well 
also  to  avoid  the  accumulation  of  blood  in  the  part.  To  prevent  this, 
saline  cathartics  are  indicated — one  that  can  be  given  is  the  official 
solution  of  magnesium  citrate,  owing  to  the  facility  with  which  it  can 
be  taken  and  its  acceptability  to  the  stomach,  a  prescription  for  which 
follows : 

I^ — Liquoris  magnesii  citratis,  f5  xij 

Sig. — Take  one  half  at  once  and  the  other  half  in   two 
hours,  if  necessary. 

An  eflfervescent  magnesium  citrate  is  now  prepared  by  pharmaceu- 
tical houses,  and  this  here  will  be  found  useful.  Magnesium  sulphate 
(Epsom  salts)  is  also  an  excellent  remedy  to  be  used  for  this  latter 
purpose.  The  patient  can  be  directed  to  take  a  teaspoonful  dis- 
solved in  a  wine-glassful  of  warm  water,  having  a  glass  of  cold  drink- 
ing water  at  hand  to  drink  at  once  after  taking  the  strong  salt  solution. 
The  cold  water  removes  at  once  the  bitter  and  unpleasant  taste  of 
the  salt.  A  very  good  remedy  to  have  the  patient  employ  at  home 
is  the  hot  foot  bath  as  explained  in  the  chapter  on  The  Treatment 
of  Pericementitis.  In  malarial  regions  and  in  the  spring  of  the  year 
in  many  localities,  the  salts  of  quinin  can  be  given,  with  beneficial 
results.  The  salt  which  the  author  prefers  giving,  if  indicated  in 
the  conditions  under  consideration,  is  quinin  bisulphate.  Nearly 
all  pharmacies  have  the  salts  of  quinin  put  up  in  the  form  of  pills. 
While  these  pills  may  be  given  it  is  much  better  to  write  a  prescription 
for  capsules.  The  gelatin  capsule  is  soon  dissolved  in  the  stomach; 
thus  we  obtain  the  action  of  the  drug  more  rapidly  than  when  given 
in  the  dry,  hard,  pilular  form.  The  following  prescription  can  be 
written  for  the  drug  in  two  grain  doses: 

I^ — Quininae  bisulphatis,  gr.  xxiv 

Ft.  capsulse  No.  12. 
Sig. — Take  one  capsule  every  hour  until  the  effect  become 
noticeable. 

Quinin  acts  differently  upon  different  individuals.  Most  adult  pa- 
tients know  the  effect  of  this  drug  upon  their  system  and  therefore 
will  be  able  to  aid  the  dentist  in  determining  the  amount  to  be  taken 
in  a  given  case. 

One  of  the  most  prominent  symptoms  with  which  we  have  to 
contend  here  is  pain.  In  most  cases  the  pain  will  subside  soon  after 
the  local  treatment;  however,  it  is  necessary  occasionally,  where  the 


362  THE  TREATMENT  OF  PUTRESCENT  PULPS. 

patient  is  nervous  and  has  lost  considerable  sleep,  to  administer 
drugs  which  act  upon  the  central  nervous  system,  thereby  controlling 
the  pain.  There  are  several  drugs  which  if  properly  given  will  pro- 
duce the  desired  efifect.  The  United  States  Pharmacopeia  of  1900 
recognizes  a  compound  powder  of  acetanilid  which  is  recommended 
and  can  be  prescribed  as  follows: 

^ — Pulveris  acetanilidi  comp.  gr.  xij 

Ft.  chartulae  No.  2. 
Sig. — Take  one  powder  at  once  and  the  other  in  two  hours, 
if  not  relieved. 

Another  very  useful  prescription  for  acetanilid  is  one  suggested  by 
the  late  Dr.  A.  W.  Harlan. 

I^ — Acetanilidi,  gr.  viij 

Syrupi  simplex,  f  5  ss 

Spiritub  frumenti,  q.  s.  ad,  £5  iij — M 

Sig. — Take  one-half   at  once  and  the  remainder  in  two 
hours,  if  not  relieved. 

Dr.  J.  E.  Keefe,  of  Chicago,  suggests  the  following  remedy  by  which 
he  claims  instantaneous  and  often  permanent  relief  can  be  obtained: 

PJ — Alcohohs, 

Aquae,  aa     fg  j— M. 

Sig. — Use  as  directed. 

This  remedy  is  best  administered  in  the  form  of  a  spray,  using  a  watch 
case  atomizer  for  liquids,  forcing  the  spray  well  back  into  the  nostril 
on  whichever  side  the  affected  tooth  is  located.  The  application 
can  be  repeated  as  often  as  is  necessary  without  any  ill  effects.  In 
case  an  atomizer  of  any  kind  is  not  at  hand,  about  fifteen  minims  of 
the  remedy  can  be  placed  far  back  in  the  nostril  with  a  suitable  syringe. 

The  author  does  not  wish  to  be  understood  as  suggesting  these 
various  internal  remedies  in  all  cases  of  acute  abscess.  No  therapeu- 
tist can  tell  exactly  what  internal  drugs  he  would  suggest  without 
seeing  the  case  and  knowing  the  history;  for  there  are  many  circum- 
stances and  conditions  which  modify  the  effect  of  drugs.  Every  rem- 
edy here  mentioned,  however,  will  be  found  useful  in  certain  cases. 

III.  Chronic  Alveolar  Abscess. — There  are  two  varieties  of 
chronic  alveolar  abscesses — those  without  an  external  opening,  ex- 
cept perhaps  through  a  cavity  in  the  offending  tooth,  and  those  which 
are  discharging  through  a  sinus.  In  these  cases  the  decomposition 
of  the  pulp  tissue  is  complete;  the  intermediate  products  (ptomains 
and  amido-acids)  have  largely  been  broken  up,  and  pus  has  been 
formed  from  the  tissue  and  fluids  surrounding  the  ends  of  the  roots 


GENERAL    CONSIDERATIONS.  363 

I.  Abscess  without  Sinus. — In  treating  that  variety  of  alveolar 
abscess  which  is  without  an  external  opening,  our  method  of  proced- 
ure is  somewhat  different.  The  tooth  should  be  located;  the  rub- 
ber dam  adjusted,  and  the  teeth  sterilized  as  before;  then  the  pulp 
chamber  is  opened  with  a  suitable  round  bur.  Usually  the  pus 
flows  freely,  in  which  case  it  is  permitted  to  do  so,  pressure  being  made 
on  the  tissue  immediately  over  the  end  of  the  root.  It  should  be  our 
effort  to  mechanically  evacuate  as  much  pus  at  each  sitting  as  is  pos- 
sible. This  being  done,  we  have  no  necessity  for  using  formaldehyd 
in  the  same  strength  solution  as  in  those  cases  where  the  pulp  chambers, 
root  canals,  and  tubuli  are  filled  with  the  intermediate  and  end-products. 
The  modified  formocresol  remedy  will  be  useful  here.  The  canals 
should  be  dried  with  alcohol  as  thoroughly  as  possible  and  the  remedy 
on  cotton  hermetically  sealed  in  each  canal.  It  is,  however,  at  this 
sitting,  impossible  to  get  the  canals  dry,  and  it  is  unnecessary  to  have 
them  so,  for  the  remedy  will  penetrate  where  moisture  is  present. 
This  is  an  advantage  over  most  remedies  suggested  for  this  purpose. 
In  those  cases  where  there  is  a  copious  flow  of  pus  at  the  first  sitting, 
the  original  formula  can  be  used,  and  the  dressing  should  be  changed 
every  day  until  it  can  be  removed  without  the  pus  flowing  from  the 
canals.  When  pus  is  forming  rapidly  at  the  end  of  the  roots,  the  dress- 
ing soon  becomes  dissipated,  the  remedy  is  neutralized,  and  it  is  a 
loss  of  time  to  leave  it  in  the  canals  more  than  twenty-four  hours. 
Unless  there  be  some  complication,  the  pus  formation  should  be  checked 
in  one  or  two  treatments;  at  which  time  the  modified  formocresol 
remedy  can  again  be  used.  It  is  now  possible  to  change  the  dressing 
too  often.  The  formation  of  pus  has  been  checked,  and  the  tooth 
should  not  be  disturbed  for  at  least  one  w^eek  or  ten  days,  in  order 
to  give  nature  a  chance  to  effect  a  cure.  If  at  the  end  of  this  time 
there  is  no  evidence  of  pus  and  the  case  gives  a  favorable  history,  the 
canals  can  be  filled.  Should  there,  however,  be  a  slight  odor  although 
the  tooth  has  not  caused  any  trouble,  we  are  not  justified  in  filling  the 
root.  In  these  cases  phenol  compound  can  be  substituted  for  formo- 
cresol and  used  with  gratifying  results.  It  should  be  remembered  that 
the  value  of  formaldehyd  in  any  remedy  to  be  used  in  the  treatment 
of  these  conditions  depends  upon  the  power  this  agent  has  of  uniting 
chemically  with  hydrogen  sulphid,  ammonia  and  poisonous  ptomains. 
When  these  substances  are  not  present,  formaldehyd,  especially  in  this 
strength  solution,  is  contraindicated.  This  precaution  is  mentioned 
here  because  formaldehyd  is  an  irritating  gas  and  any  remedy  contain- 
ing it  should  be  modified  according  to  the  conditions  as  found. 


364  THE  TREATMENT  OF  PUTRESCENT  PULPS. 

Quite  frequently  in  these  alveolar  abscess  cases,  after  the  formation 

of  pus  has  been  checked  we  have  a  weeping  of  serum  from  the  canals. 

An  excellent  remedy  to  use  in  this  case  is  eucalyptol  to  which  thymo! 

has  been  added  in  the  following  proportion: 

I^ — Thymolis,  gr.  x 

Eucalyptolis,  f5j — M. 

Sig. — Dry  the  canal  as  much  as  possible  and  hermetically 
seal  in  the  remedy. 

If  this  remedy  fails  to  check  the  secretion  and  the  fluid  is  serum 
not  pus,  no  hesitancy  need  be  felt  as  to  filling  the  root,  although  the 
canals  cannot  be  dried. 

Occasionally  we  find  a  chronic  alveolar  abscess  of  this  variety 
where  it  is  almost  impossible  to  check  the  formation  of  pus  by  apply- 
ing drugs  to  the  canals  of  the  teeth.  In  such  cases  the  radiograph  will 
aid  materially  in  determining  the  area  involved.  In  those  canals  where 
the  pus  continues  to  flow  freely  when  the  dressing  is  removed  at  the  third 
or  fourth  sitting,  some  complication  can  be  expected.  It  is  necessary 
then  to  force  some  stimulating  agent  through  the  apices  of  the  roots, 
after  the  pus  has  been  mechanically  evacuated.  The  stimulating 
agent  which  the  author  uses  almost  invariably  is  a  fifty  per  cent  solu- 
tion of  phenolsulphonic  acid.  In  resorting  to  this  means  of  bring- 
ing about  a  more  acute  condition,  I  desire  to  emphasize  the  necessity 
of  first  evacuating  the  pus  as  completely  as  possible  before  using 
the  remedy,  after  which  the  agent  should  be  gently  forced  through 
the  apices  and  the  modified  formocresol  remedy  sealed  in  the  canal. 
It  will  be  found  that  one  or  two  treatments  will  usually  check  the  for- 
mation of  pus,  after  which  the  case  can  be  treated  as  an  ordinary- 
abscess  of  this  kind.  In  case  this  method  fails  to  effect  a  cure,  however, 
it  will  be  necessary  to  surgically  establish  an  opening  through  the  over- 
lying process  and  soft  tissue  and  treat  as  for  an  ordinary  discharging 
abscess — which  treatment  will  now  be  considered. 

2.  Abscess  with  Sinus. — In  those  cases  where  the  pus  is  dis- 
charging into  the  mouth  through  a  sinus,  our  first  duty  is  to  locate  the 
offending  tooth.  This  is  generally  a  simple  matter  for  the  reason  that 
the  sinus  usually  opens  immediately  over  the  tooth  from  which  it 
comes.  The  pus  in  making  its  exit,  however,  follows  the  line  of  least 
resistance,  and  in  some  cases  the  condition  of  the  process  is  such  that 
the  pus  burrows  forward  or  backward,  and  opens  through  the  gum 
at  a  point  several  teeth  removed  from  the  one  which  is  causing  the 
trouble.  These  are  the  cases  that  are  difficult  to  diagnose,  especially 
where  the  abscess  has  been  discharging  for  some  time,  when  there  is 
not  much  tenderness  in  any  special  tooth,  and  where  there  are  several 


GENERAL    CONSIDERATIONS.  365 

pulpless  teeth  on  this  side  of  the  mouth.  Sometimes  two  teeth  con- 
taining putrescent  pulps  have  a  common  sinus.  In  this  case  it  would 
be  impossible  to  heal  the  tract  by  treating  only  one  of  the  teeth.  The 
radiograph  is  the  best  means  at  our  command  for  determining  the  tooth 
or  teeth  involved.  In  the  absence  of  the  X-ray  the  silver  probe  will  be 
found  valuable.  By  gently  working  the  probe  forward  or  backward  the 
sinus  can  be  explored  and  the  offending  tooth  or  teeth  located  without 
drilUng  into  innocent  teeth — a  discouraging  procedure  to  both  patient 
and  dentist.  The  tooth  being  located,  all  that  is  necessary  to  effect  a 
cure — there  being  no  complication — is  to  force  some  bland  solution 
through  the  root  canal  and  sinus,  thus  being  certain  it  is  well  established; 
cauterize  the  tract,  hermetically  seal  in  the  canal  or  canals  the  same  agent 
used  for  this  latter  purpose  or  the  modified  formocresol  remedy,  and,  at 
the  subsequent  sitting,  the  case  giving  a  favorable  history,  fill  the  root. 
Establishing  Sinus. — If  the  abscess  is  not  discharging,  and  it  is 
well  in  those  cases  where  it  is  discharging,  before  adjusting  the  rubber 
dam,  to  enlarge  the  mouth  of  the  sinus  with  a  lancet  or  bistoury. 
By  dipping  the  lancet  in  phenol,  this  may  be  accomplished  with  very 
little  pain  to  the  patient.  After  this  is  done  the  rubber  dam  should 
be  adjusted  and  the  canals  freely  exposed.  Now  that  the  infection 
is  past  the  end  of  the  root,  we  need  not  hesitate  to  mechanically  clean 
the  canal  at  this  sitting.  The  canals  being  clean  we  are  ready  to 
establish  the  sinus.  To  do  this  we  need  a  bland  solution  and  a  good 
hypodermic  syringe  with  a  long  straight  needle  for  anterior  and  a  long 
curved  needle,  for  posterior  teeth.  There  is  an  advantage  in  having 
a  long  needle,  for  the  nearer  the  point  is  to  the  apex  of  the  root,  the 
less  packing  and  force  is  required  to  send  the  solution  through  the  sinus. 
Any  bland  solution  can  be  used  for  this  purpose.  The  author  suggests 
peppermint  water  to  which  two  minims  of  phenol  has  been  added  to 
the  fluid  ounce.  Physiologic  salt  solution  is  also  good.  A  piece  of 
unvulcanized  rubber  of  the  proper  size  should  be  selected,  softened  in 
the  flame,  and  a  hole  made  in  the  center  through  which  the  needle  is 
placed  and  inserted  into  the  canal.  The  rubber  should  now  be 
tightly  packed  around  the  needle  and  held  on  either  side  with  flat 
nose  pliers,  when  pressure  can  be  made  on  the  piston  of  the  syringe 
and  the  solution  forced  through  the  sinus.  This  should  be  repeated 
several  times,  care  being  taken  not  to  break  the  needle  in  the  canal. 
If  convenient  one  comer  of  the  dam  can  be  raised,  exposing  the  mouth 
of  the  sinus  to  view.  There  are  two  objects  in  forcing  a  bland  solution 
through  the  sinus:  one  is  to  be  certain  that  it  is  open,  and  the  other  is  to 
mechanically  wash  out  the  pus.     Whenever  pus  can  be  mechanically 


366  THE  TREATMENT  OF  PUTRESCENT  PULPS. 

removed,  it  is  always  better  to  dispose  of  it  by  this  means  rather  than  to 
do  so  by  the  use  of  some  chemical  agent.  It  is  common  practice  after 
the  sinus  is  established  to  use  a  solution  of  hydrogen  dioxid.  This  is 
often  a  dangerous  procedure  and  always  unnecessary  if  the  first  solution 
has  been  used  in  sufiScient  quantity.  For  cauterizing  the  sinus  in  simple 
cases  ninety-five  per  cent  phenol  has  been  largely  employed.  An  ex- 
cellent preparation  to  use  for  this  purpose  is  phenol  compound.  With 
the  sinus  well  established,  it  is  never  necessary  to  place  either  of  these 
solutions  in  a  hypodermic  syringe.  The  author  knows  of  several  in- 
stances where  this  has  been  tried  with  disastrous  results.  The  remedy 
can  be  applied  to  the  canals  on  cotton,  when,  with  unvulcanized  rub- 
ber and  a  suitable  instrument,  it  can  be  forced  through  the  sinus. 
Alcohol  is  a  positive  antidote  for  phenol;  the  alcohol  bottle  should 
therefore  be  in  a  convenient  place  so  that  the  remedy  used  in  the  canal 
can  be  neutralized  at  once  when  it  appears  at  the  mouth  of  the  sinus. 
If  this  has  been  well  done,  it  matters  little  what  drug  or  remedy  is 
sealed  in  the  canal.  The  phenol  compound  or  the  modified  formo- 
cresol  solution  will  give  excellent  results  if  hermetically  sealed  in  the 
canals  for  about  one  week.  In  cases  of  long  standing  when  we  can 
reasonably  suspect  a  roughening  of  the  end  of  the  root  or  process 
through  which  the  pus  has  been  discharging,  it  is  good  practice  to  use, 
as  the  cauterizing  agent,  a  fifty  per  cent  solution  of  phenolsulphonic 
acid,  and  in  stubborn  cases  the  pure  acid  can  be  employed.  The  author 
does  not  believe  in  delaying  the  root  filling  long  after  the  sinus  has  been 
cauterized  in  uncomplicated  cases;  for  by  filling  the  root  as  soon  as  we 
are  certain  that  the  sinus  is  healing,  we  avoid  a  weeping  condition,  which 
usually  exists  and  which  is  annoying  when  this  part  of  the  treatment  is  de- 
layed for  one  month  or  six  weeks  as  advocated  by  some  writers.  In 
these  cases  where  the  first  treatment  has  been  thorough,  and  the  case 
gives  a  favorable  history,  the  root  should  be  filled  at  the  second,  or,  at 
most,  at  the  third  sitting.  If  the  case  does  not  yield  to  the  above  treat- 
ment, some  complication  may  be  expected. 

It  is  sometimes  difficult  to  estabhsh  the  sinus,  especially  on  molar 
teeth.  In  all  such  cases  where  there  is  no  complication,  the  case 
can  be  nicely  treated  with  the  formocresol  solution  as  outlined  under 
treatment  of  abscess  without  sinus.  Before  referring  to  complicated 
cases  the  treatment  of  putrescent  pulps  and  abscesses  associated  with 
deciduous  teeth  will  be  considered. 

Treatment  of  Putrescent  Pulps  and  Abscesses  in  Deciduous  Teeth. — 
In  treating  the  conditions  under  consideration,  in  the  mouths  of 
children,  it  is  necessary  in  most  cases  to  modify  our  usual  method 


GENERAL    CONSIDERATIONS.  367 

of  treatment.  Our  first  duty  here  is  to  gain  the  confidence  of  the 
child.  If  the  abscess  is  associated  with  a  deciduous  molar  which  we 
would  desire  to  save  for  at  least  a  year  or  two,  it  can  be  treated  nicely 
in  the  following  manner:  After  gaining  the  confidence  of  the  little 
patient  the  mouth  can  be  rinsed  with  an  antiseptic  solution — one  which 
has  a  pleasant  taste.  Then  open  into  the  pulp  chamber  and  place 
a  pledget  of  cotton  in  the  opening.  Now  mix  on  one  end  of  the  ce- 
ment slab  thymolized  calcium  phosphate  and  the  formocresol  remedy, 
making  a  stiff  paste.  On  the  other  end  of  the  slab  have  a  quick  set- 
ting cement  ready  to  mix.  Again  rinse  the  patient's  mouth  and,  keeping 
the  cavity  as  dry  as  possible,  gently  pack  the  paste  into  the  pulp 
chamber  and  flow  the  cement  over  it,  filling  the  cavity.  If  deemed 
advisable,  the  cavity  can  be  prepared  in  the  cement  and  filled  with 
amalgam.  It  is  remarkable  how  rapidly  these  abscesses  will  heal  and 
remain  quiet  when  treated  in  this  manner,  provided,  of  course,  there 
be  no  caries  or  necrosis  of  bone. 

Complications. — There  are  several  complications  of  chronic  al- 
veolar abscess  of  both  varieties,  with  and  without  a  sinus,  where  it  is 
necessary  to  modify  or  change  the  general  method  of  treatment  to 
meet  the  conditions  as  they  exist.  For  instance,  in  the  case  of  an 
abscess  without  a  sinus  where  we  can  reasonably  suspect,  and  where 
the  indications  point  to  a  roughening  of  the  end  of  the  root,  we  ought 
not  to  expect  to  cure  the  case  by  simply  sealing  remedies  within  the 
canals  of  the  tooth.  If  we  do,  we  are  expecting  too  much  of  drugs. 
Again,  in  a  case  of  an  abscess  with  a  sinus  where  the  pus  has  been  dis- 
charging for  several  months,  with  the  not  unusual  result  that  the  end 
of  the  root  or  process  through  which  the  pus  has  discharged  has 
become  roughened,  we  should  not  expect  to  effect  a  cure  by  forcing 
phenol  or  phenol  compound  through  the  sinus;  because  such  agents  as 
these  have  no  action  whatever  on  the  bony  structures. 

I.  Denuded  End  0}  Root. — One  complication  we  may  expect  to 
find  in  abscesses  of  long  standing,  especially  in  the  variety  without 
a  sinus,  is  where  a  large  area  of  tissue  in  the  apical  space  has  been  ab- 
sorbed or  broken  down,  denuding  the  end  of  the  root  and  the  denuded 
portion  projecting  into  the  absorbed  area.  It  is  possible,  in  these 
cases,  to  make  pressure  over  the  end  of  the  root  and  mechanically 
evacuate  all  of  the  pus  above  the  apices;  but  we  cannot  expect  by 
this  means  to  evacuate  the  pus  below  and  surrounding  the  end  of  the 
root  projecting  into  the  space.  In  this  case  we  must  do  one  of  two 
things:  Force  some  stimulating  agent  through  the  end  of  the  root 
into  the  infected  area,  to  create  a  more  acute  condition,  or  surgically 


368  THE  TREATMENT  OF  PUTRESCENT  PULPS. 

establish  a  sinus  through  the  overlying  process  and  soft  tissue  and 
treat  as  an  ordinary  discharging  abscess.  While  the  author  does  not 
hesitate  to  adopt  the  latter  method  if  necessary  to  effect  a  cure,  it 
will  be  found  that  the  use  of  a  stimulating  agent  will  generally  suffice 
in  these  cases.  The  agents  recommended  are  a  fifty  per  cent  solution 
of  phenolsulphonic  acid,  or  a  fifteen  per  cent  solution  of  trichloracetic 
acid.  In  using  either  of  these  solutions  the  pus  should  first  be  evac- 
uated as  much  as  is  possible;  then  the  solution  selected  can  be  placed 
in  the  canal  and  gently  forced  through  the  apices  and  the  modified 
formocresol  solution  sealed  in  the  canal.  One  or  two  treatments  will 
usually  be  sufficient  to  check  the  pus  formation,  when  the  case  can  be 
treated  in  the  ordinary  manner. 

2.  Resorted  Root. — ^Another  complication  of  both  varieties  of 
chronic  alveolar  abscess  is  where  the  pus  has  stood  in  contact  with 
the  end  of  the  root  sufficiently  long  to  cause  resorption,  leaving  a 
roughened  end  which  irritates  the  tissue  and  prevents  healing.  Some- 
times, also,  the  process  through  which  the  pus  has  burrowed  is  left 
with  sharp  edges.  In  all  such  complications  the  "acid  treatment" 
is  especially  indicated.  These  cases  generally  yield  nicely  to  the  treat- 
ment if  phenolsulphonic  acid  is  used  as  the  agent  with  which  to  cau- 
terize the  sinus. 

3.  Eficystmeni  of  Root. — A  difficult  complication  to  treat  is  where 
an  abscess  occurs  on  a  root,  the  end  of  which  has  become  encysted 
from  deposits,  excementosis  or  other  causes.  In  order  to  effect  a  cure 
in  these  cases,  it  is  necessary  to  establish  a  sinus  and  remove  the  de- 
posits, excise  the  root-end,  or  extract  the  tooth.  The  method  of  excis- 
ing the  root-end  will  be  discussed  later. 

4.  Involving  Vault. — Still  another  complication  often  difficult  to 
cure  is  where  the  pus  has  worked  its  way  through  the  lingual  plate  of 
bone  and  involves  the  vault  of  the  mouth.  The  dense  fibrous  tissue 
covering  the  vault  is  very  tough  and  the  pus  often  separates  the  perios- 
teum from  a  considerable  area  of  bone  before  ultimately  discharging 
into  the  mouth.  Generally  a  lancet  is  required  to  evacuate  the  pus. 
In  treating  these  conditions  it  is  essential  to  explore  the  affected  area, 
using  a  sharp  steel  instrument  in  order  to  determine  whether  there  is 
caries  or  necrosis.  Unles"  too  much  bone  is  involved  the  case  can  be 
successfully  treated  by  first  making  a  liberal  opening  with  a  sharp 
bistoury  and,  if  necessary,  breaking  down  the  sharp  edges  of  bone, 
through  which  the  pus  has  burrowed,  with  a  round  bur  having  a  long 
shank,  after  which  the  sinus  should  be  established  in  the  usual  manner, 
using  a  considerable  quantity  of  the  bland  solution.     Now  dry  the 


GENERAL    CONSIDERATIONS.  369 

canal  and  force  through  the  sinus  full  strength  phenolsulphonic  acid. 
Sometimes  it  is  advisable  to  place  a  piece  of  blotting  paper  soaked  in 
liquid  petroleum  over  the  lingual  opening  when  forcing  the  acid  through. 
This  causes  the  agent  to  spread  and  come  in  contact  with  the  entire 
area  involved.  Alcohol  and  the  oils  will  neutralize  any  excess  of  the 
phenolsulphonic  acid  that  may  get  on  the  other  tissues  of  the  mouth. 
This  treatment  should  be  repeated  as  often  as  the  case  demands. 
When  there  is  no  evidence  of  pus  and  the  case  has  healed  sufficiently  so 
that  there  is  only  a  watery  discharge  the  root  can  be  filled. 

5.  Secondary  Abscess  Pocket. — Occasionally  we  find  an  abscess 
of  the  discharging  variety  which  does  not  yield  to  our  general  treat- 
ment, yet  we  are  reasonably  certain  that  none  of  the  complications 
so  far  mentioned  are  present.  In  these  cases  we  can  suspect  a  secon- 
dary abscess  pocket.  This  is  especially  true  where  the  sinus  opened 
into  the  mouth  several  teeth  removed  from  the  affected  tooth.  This 
pocket  can  usually  be  discovered  by  the  aid  of  a  small  silver  probe. 
The  treatment  is  simple — all  that  is  necessary  is  to  open  the  pocket, 
wash  it  out  first  with  a  bland  solution,  then  inject  fifty  per  cent  phenol- 
sulphonic acid.  In  using  phenolsulphonic  acid  in  such  cases  it  cannot 
be  injected  through  the  tooth,  therefore  it  is  necessary  to  use  a  syringe 
— a  glass  syringe  with  an  asbestos-packed  plunger  and  a  gold  or  a  plat- 
inum needle  should  be  used. 

6.  Involving  Antrum. — The  pus  in  making  its  exit  follows  the 
line  of  least  resistance,  and  sometimes  it  is  easier  to  work  its  way 
through  the  floor  of  the  antrum  than  through  the  labial  or  lingual 
plate  of  bone.  The  treatment  of  this  complication  will  not  be  dis- 
cussed here;  but  in  this  connection  it  is  well  to  remember  that  so  good 
an  authority  as  Kyle,  viewing  the  question  from  the  nasal  side,  finds 
that  fully  fifty  per  cent  of  antral  diseases  are  of  dental  origin. 

Excision  of  Root-end. — In  all  complicated  abscesses  which  will  not 
yield  to  the  treatment  outlined  above,  we  can  often  save  the  root  by 
excising  its  end.  This  should  be  done  only  as  a  last  resort  and  then 
under  the  most  aseptic  measures.  The  hands  of  the  operator,  as  well 
as  all  instruments  used,  should  be  thoroughly  sterilized.  Before 
operating,  the  root  should  be  filled  and  a  thorough  exploration  made 
that  the  amount  of  process  and  root  involved  may  be  noted.  A  local 
anesthetic  injected  deeply  should  be  employed  and  an  incision  should 
be  made.  If  only  one  tooth  is  involved  the  author  prefers  following 
the  general  method  of  Dr.  M.  I.  Shamberg,  of  New  York.  The  incision 
is  made  immediately  over  and  parallel  with  the  affected  root.  With 
a  periosteotome  the  tissues  are  deflected  on  either  side  of  the  incision 
24 


37©  THE  TREATMENT  OF  PUTRESCENT  PULPS. 

and  held  back  by  the  author's  tissue  retractor.  We  now  have  the  root- 
end  exposed  to  view,  when  it  can  be  excised  or  burred  off  as  is  indicated. 
After  removing  the  excised  end,  the  root  remaining  should  be  smoothed 
with  a  round  bur  and  the  area  thoroughly  curetted,  removing  any 
necrosed  process  which  may  be  present.  The  wound  should  now  be 
washed  with  an  antiseptic  solution  and  packed  with  sterile  gauze.  The 
patient  should  be  instructed  to  keep  the  mouth  as  clean  as  possible  and 
the  packing  should  be  changed  every  two  days  until  granulation  begins 
to  fill  the  space.  For  a  more  detailed  description  of  the  surgery  of 
chronic  alveolar  abscess  see  the  author's  work  on  Dental  Therapeutics. 

Whenever  the  operator  is  in  doubt  as  to  the  best  means  of  treating 
complicated  alveolar  abscesses,  he  should  never  hesitate  to  consult 
with  a  practitioner  who  has  had  more  experience  in  treating  these 
cases.  Such  a  course  cannot  be  construed  as  a  lack  of  knowledge, 
but  is  evidence  of  conservatism  and  progress. 

Pericemental  Abscess. — All  of  the  alveolar  abscesses  which  we  have 
discussed  thus  far  in  this  chapter  have  been  the  result  of  an  infection 
in  the  apical  area,  the  infection  being  due  to  pathogenic  bacteria, 
poisonous  ptomains  and  irritating  gases,  which  have  escaped  from  a 
putrescent  root  canal.  There  is,  however,  an  abscess  that  occurs  in 
the  alveolar  region  about  the  roots  of  teeth,  not  caused  from  the  source 
mentioned.  This  particular  kind  of  abscess  occurs  in  connection 
with  live  teeth;  not  necessarily  so,  however.  There  is  a  progressive 
breaking  down  of  the  pericemental  membrane  and  in  dental  literature 
it  is  called  a  pericemental  abscess.  The  cause  of  this  particular 
kind  of  abscess  is  rather  vague;  but  it  is  generally  supposed  to  be  due 
to  some  traumatic  injury.  It  frequently  occurs  on  the  labial  surface 
of  the  roots  of  the  anterior  teeth  involving  most  of  this  surface.  They 
have  also  been  known  to  occur  between  the  roots  of  molar  teeth,  es- 
pecially the  upper  molars.  While  a  pericemental  abscess  is  often 
associated  with  pyorrhea  alveolaris,  care  should  be  exercised,  in  mak- 
ing the  diagnosis,  not  to  get  this  condition  confused  with  the  latter 
disease. 

Treatment. — ^For  convenience  in  outlining  our  treatment  for  a 
pericemental  abscess,  the  condition  may  be  classified  as  acute  and 
chronic.  As  a  rule  there  is  very  little  pain  associated  with  either 
variety  of  pericemental  abscess.  In  the  acute  form,  which,  as  such, 
is  extremely  difficult  to  diagnose,  the  patient  will  complain  of  "  some- 
thing being  wrong  with  a  particular  tooth."  About  all  that  can  be 
done  therapeutically  with  the  acute  form  is  to  pacify  the  patient 
as  best  we  can  until  the  acute  abscess  develops  into  the  chronic  variety 


GENERAL    CONSIDERATIONS.  371 

when  pus  is  formed  and  discharges  usually  at  the  gum  margin,  and 
thus  the  diagnosis  is  more  easily  made.  If  the  abscess  occurs  on  the 
anterior  teeth  where  the  area  involved  can  be  curetted  and  cauterized 
it  will  generally  yield  to  the  treatment;  but  the  treatment  of  a  chronic 
pericemental  abscess  on  molar  teeth  is  at  best  a  discouraging  procedure 
and  practically  the  only  permanent  cure  is  to  extract  the  affected  tooth. 
In  those  cases  where  the  area  can  be  reached,  an  opening,  if  necessary, 
can  be  made  through  the  gum,  the  root  thoroughly  scraped  and  pol- 
ished, then  after  washing  out  the  abscessed  area,  it  should  be  cauterized 
with  some  cauterizing  agent.  Nothing  gives  better  results  than  phenol- 
sulphonic  acid.  With  a  proper  glass  syringe  and  a  gold  or  platinum 
needle,  the  remedy  can  be  injected  into  the  abscess  pocket.  One 
thorough  treatment  should  effect  a  cure.  In  curetting  these  cases  it  is 
far  better  to  go  a  little  beyond  the  affected  territory  rather  than  fail 
to  remove  all  of  the  affected  tissue  and  have  the  abscess  recur.  Where 
the  abscess  can  be  reached,  thorough  curettment  and  cauterization 
will  effect  a  cure.  That  portion  of  the  pericemental  membrane  which 
has  been  destroyed  will  perhaps  never  be  regenerated,  but  if  we  succeed 
in  having  granulation  fill  in  the  area  involved,  even  though  the  mem- 
brane is  not  regenerated  over  that  particular  surface  of  the  root,  the 
tooth  can  be  saved  for  a  considerable  length  of  time. 

Filling  Root  Canals. — There  are  so  many  different  methods  of 
filling  root  canals,  and  there  seems  to  be  such  a  variance  of  opinion 
as  to  the  best  method  of  performing  this  operation,  that  it  is  with  a 
degree  of  hesitancy  that  the  author  attempts  to  discuss  this  subject. 
This  operation  stands  as  a  sort  of  dividing  line  between  the  subjects 
of  therapeutics  and  operative  dentistry  proper.  In  discussing  this 
subject  the  author  will  present  the  therapeutic  aspect  and  describe 
a  method  of  procedure  which  has  proved  successful  in  his  practice. 

It  will  be  remembered  that  three  factors  were  emphasized  in  the 
chapter  on  pulp  removal  and  the  subsequent  treatment,  viz.: 

1.  Established  and  maintained  asepsis, 

2.  Preserve  the  color  of  the  tooth. 

3.  Thoroughly  fill  the  canal. 

The  author  suggests  filling  all  canals,  which  are  large  enough  for  a 
broach  to  enter,  with  gutta-percha  in  the  manner  which  will  be  sub- 
sequently described.  In  connection  with  the  preservation  of  the  color 
of  the  tooth,  it  should  be  mentioned  that  white  base  plate  gutta-percha 
should  be  used,  especially  for  the  purpose  of  dissolving  in  chloroform, 
or  eucalyptol  compound,  making,  respectively,  chloro-percha  and  euca- 
percha  compound.      If  this  white  substance  is  forced  into  the  tubuli  of 


372  THE  TREATMENT  OF  PUTRESCENT  PULPS. 

the  crown  of  the  tooth,  as  it  is  liable  to  be,  it  will  not  change  the  color 
of  the  tooth  structure  as  would  the  pink  gutta-percha.  A  great  many 
dentists  have  been  moistening  the  canal,  previous  to  filling  with  gutta- 
percha, with  oil  of  eucalyptus;  and,  as  a  result,  much  unnecessary 
pericementitis  has  followed  this  operation.  If  oil  of  eucalyptus  is 
used  at  all,  the  refined  oil  only  should  be  selected;  and,  far  more  satis- 
factory results  will  follow  the  use  of  eucalyptol,  the  most  volatile  con- 
stituent of  oil  of  eucalyptus.  While  eucalyptol  is  irritating,  it  is  not 
nearly  as  much  so  as  is  oil  of  eucalyptus.  The  author  suggests  modify- 
ing the  irritating  property  of  eucalyptol  and  enhancing  its  antiseptic 
power  by  combining  menthol  and  thymol  as  suggested  in  the  prescrip- 
tion for  modified  eucalyptol  in  the  chapter  on  The  Treatment  of 
Ordinary  Pericementitis. 

In  this  proportion  the  agents  added  do  not  interfere  with  the  solvent 
power  of  eucalyptol  for  gutta-percha;  but  if  the  amounts  are  increased 
to  any  appreciable  extent  this  does  not  hold  true. 

In  filling  root  canals  it  is  always  the  safest  practice  to  adjust  the 
rubber  dam,  for  asepsis  must  be  established  and  maintained.  The 
same  agents  can  be  used  for  sterilizing  the  teeth  after  the  dam  is  ad- 
justed as  were  described  in  removing  pulps  by  the  anesthetization 
method.  The  canals  should  be  aseptic  before  the  operation  is  at- 
tempted. If  there  is  any  doubt  in  this  regard  the  operation  should  be 
deferred  until  the  canals  are  in  such  a  condition. 

Filling  Large  Canals. — In  filling  large  canals,  especially  those 
in  connection  with  which  abscesses  have  been  treated,  where  the  apex 
is  large  and  where  we  ought  not  to  expect  to  get  a  response  from  the 
patient  when  the  gutta-percha  cone  reaches  the  apex,  on  account  of 
the  absorption  in  the  apical  area,  it  is  best  to  measure  the  canal  and 
then  use  one  cone  which  approximately  fits  the  canal  rather  than  use 
two  or  three  smaller  cones  with  the  possibility  of  forcing  one  through 
the  apex  and  into  the  apical  area.  There  is  almost  as  much  danger 
of  forcing  the  root  filling  too  far  in  large  canals,  as  there  is  in  not  forcing 
it  far  enough  in  small  canals.  To  measure  the  canal,  cotton  can  be 
tightly  wrapped  around  a  smooth,  sterile  broach  and  inserted.  When, 
by  repeated  trials  the  cotton  fits  the  canal,  a  cone  can  be  made  of  white 
base  plate  gutta-percha,  which  is  slightly  smaller  than  the  tightly 
wrapped  cotton.  The  canal  should  now  be  moistened  with  modified 
eucalyptol,  flooded  with  white  eucapercha  compound,  working  the  latter 
up  or  down  into  the  canal  with  a  fine  smooth  broach,  exhausting  the  air. 
If  cotton  is  wrapped  around  the  broach  used  for  this  latter  purpose, 
only  a  few  shreds  should  be  used;  for  we  should  avoid  making  a  piston 


GENERAL    CONSIDERATIONS.  373 

out  of  the  broach  and  thus  defeating  the  means  of  exhausting  the  air. 
This  accomplished,  the  cone  can  be  slowly  and  gently  pressed  to  place. 
In  filling  large  canals  from  which  live  pulps  have  recently  been  re- 
moved, the  patient  will  generally  flinch  before  the  cone  reaches  the 
apex.  When  this  occurs,  we  should  wait  a  few  moments,  when  the  cone 
can  be  gently  pressed  much  farther  without  causing  the  patient  to 
flinch  a  second  time.  If  these  precautions  are  observed,  they  will  be 
the  means  of  preventing  much  of  the  pericementitis  following  the 
filling  of  root  canals. 

Small  Canals. — In  filling  all  canals  where  we  can  enter  nicely 
with  a  smooth  broach,  it  is  best  to  follow  the  technique  outlined  above, 
using  a  cone  which  will  enter  the  canal.  However  much  we  may  re- 
gret it,  there  are  canals,  especially  in  the  molar  teeth,  so  small  and 
tortuous  that  even  a  fine,  smooth  broach  will  not  enter;  at  least  to  any 
depth.  It  is  useless  to  try  to  fill  such  canals  with  a  gutta-percha  cone. 
The  methods  of  enlarging  the  canals  by  the  use  of  acids  and  caustics, 
as  referred  to  in  connection  with  the  destruction  of  pulp  tissue  in  such 
canals,  can  be  employed;  but  it  is  not  always  advisable  to  enlarge 
them  sufficiently  to  admit  a  small  cone.  After  the  larger  canal  or 
canals  in  a  multirooted  tooth  are  filled  in  the  ordinary  manner,  the 
smaller  ones  can  be  flooded  with  eucapercha  compound  and  this  prepa- 
ration worked  up  or  down  into  the  canal.  This  process  should  be 
kept  up  for  some  time  until  we  are  certain  that  all  air  has  been  expelled 
and  the  canal  filled  with  the  plastic  material.  The  sides  of  the  pulp 
chambers  can  now  be  moistened  with  eucapercha  compound  and  a  piece 
of  base  plate  gutta-percha,  selected  and  softened  in  the  flame,  can  be 
packed  into  the  pulp  chamber,  when  pressure  can  be  made  towards  the 
small  canals  and  the  plastic  gutta-percha  forced  into  them.  This  is 
much  better  practice  than  simply  filHng  the  mouth  of  the  canal  with  a 
gutta-percha  cone.  If  the  canal  is  so  small  and  tortuous  that  even  a 
small  broach  will  not  enter,  and  if  it  cannot  be  enlarged  by  the  use  of 
acids  or  caustics,  as  referred  to  in  a  previous  chapter,  it  is  good  practice 
to  make  a  paste  of  formocresol  and  thymolized  calcium  phosphate, 
placing  the  paste  over  the  mouth  of  the  canal  and,  after  absorbing  the 
excess  liquid  with  cotton  or  bibulous  paper,  covering  it  with  cement. 

As  previously  mentioned  there  are  many  methods  of  filling  root 
canals  by  which  good  results  are  attained.  The  method  here  outlined 
has  served  the  author  well.  In  closing  this  chapter  I  desire  to  say 
that  no  reasonable  amount  of  time  should  be  considered  lost  in  treat- 
ing the  conditions  discussed  in  this  chapter  and  in  properly  preparing 
canals  for  the  insertion  of  the  filling  material. 


CHAPTER  XXIIl. 

THE  CAUSES  AND  TREATMENT  OF  DISCOLOR- 
ATIONS  OF  TEETH. 

BY    J.    P.    BUCKLEY,    PH.G.,  D.  D.  S. 

General  Considerations. — In  the  discussion  of  the  methods  of 
removing  pulps  from  teeth  and  the  subsequent  treatment,  the  treating 
of  putrescent  pulps  and  the  various  kinds  of  alveolar  abscesses,  the 
author  endeavored  to  emphasize  the  necessity  of  preserving  or  restoring 
the  color  of  the  tooth.  There  is,  perhaps,  nothing  more  annoying  to  a 
conscientious  dentist  and  to  an  appreciative  patient  than  a  discolored 
tooth  in  the  patient's  mouth.  If  the  precautions,  vi^hich  have  been 
mentioned  in  the  preceding  chapters,  with  reference  to  this  factor 
are  observed  in  the  treatment  of  teeth,  the  necessity  for  bleaching 
may  often  be  avoided ;  for  after  all  that  has  been  written  on  this  subject 
is  studied,  it  must  be  admitted  that  the  most  successful  method  of 
bleaching  teeth  is  to  so  treat  them  that  they  will  not  need  to  be  bleached. 
There  are  three  principal  sources  of  the  discoloration  of  tooth  struc- 
ture, viz.,  pulp  decomposition,  remedial  agents  and  metallic  fillings. 
The  greatest  source  is  that  of  pulp  decomposition.  Many  teeth  con- 
taining putrescent  pulps  are  discolored  before  the  patient  presents 
for  treatment.  In  those  cases  where  the  color  is  not  lost  the  putrescent 
condition  can  be  corrected  and  the  color  preserved  by  the  method  of 
treatment  outlined  in  a  previous  chapter. 

There  are  two  ways  by  which  the  discoloration  is  produced, 't.  e., 
by  solutions  which  stain  the  cement-like  substance  uniting  the  tubuli, 
and  by  the  ingress  into  the  tubuli  of  insoluble  coloring  substances. 
For  instance,  many  remedial  agents  in  solution  such  as  oil  of  cassia, 
silver  nitrate,  etc.,  have  the  property  of  staining  the  cementing  sub- 
stance and  producing  discolorations;  while  the  sulphids  formed  from 
certain  metals,  as  for  example  in  amalgam  fillings,  produce  discolor- 
ation by  virtue  of  being  forced  into  the  tubular  structure  of  the  dentin. 
If  more  care  were  taken  in  selecting  remedial  agents,  used  in  the 
treatment  of  teeth,  which  would  not  stain  the  tooth  structure,  and  if 
high  grade  alloys  were  selected  in  making  amalgam  fillings,  the  cavity 

375 


376       CAUSES    AND    TREATMENT    OF    DISCOLORATIONS    OF    TEETH. 

properly  prepared,  amalgam  inserted  and  polished  when  set,  there 
would  be  few  teeth  discolored  from  these  sources. 

Occasionally,  however,  teeth  have  been  observed  to  assume  a 
pinkish  hue  shortly  after  some  traumatic  injury,  rapid  regulation 
or  after  the  application  of  some  irritating  drug  had  been  applied 
to  some  small  exposure  of  the  pulp  as,  for  instance,  arsenic  trioxid. 
It  was  stated  in  a  previous  chapter,  that  it  is  always  best  to  apply 
arsenic  trioxid  to  the  dentin  immediately  over  the  pulp,  even  though 
an  exposure  exists.  Dr.  E.  C.  Kirk,  of  Philadelphia,  has  offered  a 
plausible  explanation  for  the  cause  of  this  immediate  discoloration. 
He  says,  **  It  is  now  known  that  the  pink  staining  of  the  tooth  is  brought 
about  by  a  rupture  of  the  stroma  of  the  red  blood  disks  liberating  their 
contained  hemoglobin,  which  dissolves  in  the  plasma,  forming  a 
solution  of  hemoglobin  which  readily  penetrates  the  dentinal  tubuli, 
the  lumen  of  which  is  of  insufficient  diameter  to  admit  the  unbroken 
red  corpuscle.  This  pink  discoloration  resulting  from  the  infiltration 
of  hemoglobin  solution  represents  the  first  stage  of  tooth  discoloration. 
The  pink  stain  readily  undergoes  alterations,  later  on  assuming  a 
brownish  tint,  due  to  the  breaking  down  of  the  highly  complex  mole- 
cule of  hemoglobin  into  a  reduction  product  known  as  hematin." 
But  as  has  been  stated,  many  teeth  containing  putrescent  pulps  are 
discolored  before  the  patient  presents  for  treatment,  and  inasmuch 
as  this  is  by  far  the  greatest  source  it  is  well  to  try  to  ascertain  definitely 
the  true  cause  of  the  discolorations  from  this  source;  for,  it  is  difficult 
and  unsatisfactory  to  try  to  bleach  a  tooth  when  we  have  no  knowledge 
of  the  nature  of  the  pigment  we  are  trying  to  bleach. 

The  principle  which  governs  the  successful  bleaching  of  teeth 
is  to  chemically  change  the  molecule  of  the  pigment  in  such  a  manner 
as  to  destroy  its  color,  or  chemically  change  the  insoluble  coloring 
substance  to  a  soluble  form,  when  it  can  be  washed  out  of  the  tooth 
structure.  Attention  will  now  be  directed  to  the  cause  of  discoloration 
from  pulp  decomposition  as  the  author  understands  it.  In  the  chapter 
on  the  Chemistry  of  Pulp  Decomposition,  the  intermediate  and 
end-products  resulting  from  this  complicated  process  were  enumerated 
and  it  was  ascertained  that  ammonia,  NH,,  and  hydrogen  sulphid, 
H^S,  were  the  principal  gases  formed.  It  was  also  pointed  out  that 
the  relative  amount  of  nitrogen  and  sulphur  found  in  the  proteid 
molecule  was  fifteen  per  cent  of  the  former  to  0.3  per  cent  of  the 
latter;  and  from  this  fact  it  was  reasoned  that  ammonia,  a  compound 
of  nitrogen  and  hydrogen,  was  generated  in  far  greater  quantities  in  a 
putrescent  root  canal,  than  hydrogen  sulphid,  a  compound  of  hydrogen 


GENERAL    CONSIDERATIONS.  377 

and  sulphur;  and  that  this  latter  gas  did  not  assume  the  important 
r61e  in  the  discoloration  of  teeth  from  this  source,  as  had  been  so 
generally  supposed. 

It  is  quite  generally  conceded  by  those  who  have  given  this  phase 
of  the  decomposition  process  their  attention,  that  iron,  Fe,  is  the 
most  important  element  to  be  considered  in  the  many  factors  entering 
into  the  discoloration  problem;  and  it  is  a  common  statement  found 
in  our  text-books  and  journals  that  the  discoloration  is  due  to  the 
formation  of  ferrous  sulphid,  FeS,  which  salt  is  supposed  to  be 
formed  by  the  action  of  hydrogen  sulphid  upon  the  iron.  This  view 
is  held  by  many  writers,  among  whom  is  Dr.  Kirk,  who  has  perhaps 
given  more  thought  to  this  subject  than  any  other  writer.  The  source 
of  iron  has  been  considered  entirely  from  the  decomposition  of  the 
hemoglobin  of  the  red  blood  corpuscles;  for  it  is  well  known  that  this 
compound  contains  iron,  which  is  not  characteristic  of  all  proteid 
bodies.  Dr.  J.  E.  Hinkins,  of  Chicago,  in  his  analysis  of  the  enamel 
and  dentin  of  human  teeth,  found  that  iron  existed  in  both  of  these 
structures  in  combination  with  aluminum.  It  is  not  unlikely  that 
future  investigation  will  find  that  the  iron  from  this  source  plays  a 
part  in  the  discoloration  of  tooth  structure.  It  remains,  however, 
to  be  demonstrated  that  ferrous  sulphid  is  the  true  cause  of  the  dis- 
coloration and  the  author  doubts  if  this  theory  can  ever  be  proved 
to  be  correct.  From  chemistry  we  learn  that  ferrous  sulphid  is  a 
Uack  compound  and  that  no  change  takes  place  in  the  color  or  other- 
wise by  exposing  it  to  the  air.  Should  the  discoloration  of  tooth 
structure  be  due,  then,  to  ferrous  sulphid,  as  claimed  by  many  writers, 
there  would  be  no  necessity,  in  treating  putrescent  pulps,  so  far  as 
preserving  the  color  of  the  tooth  is  concerned,  for  using  a  remedy 
which  can  be  hermetically  sealed  within  the  tooth.  Clinical  ex- 
perience shows  that  a  tooth  containing  a  recently  decomposed  pulp, 
in  a  large  percentage  of  cases,  is  not  discolored,  and  that  such  a  tooth 
will  not  change  in  color  if  the  formocresol  remedy  is  used  in  the 
treatment  and  always  hermetically  sealed. 

Dr.  Kirk  admits  that,  "Ferrous  sulphid,  as  such,  cannot  be  held 
wholly  accountable  for  the  bluish-black  color  of  the  tooth  which  has 
reached  the  stage  of  permanent  discoloration."  Neither  can  the  green 
nor  yellow  discolorations  of  teeth  be  attributed  in  any  way  to  the  presence 
of  black  ferrous  sulphid;  yet,  the  author  is  of  the  opinion  that  it  is 
possible  for  this  compound  to  be  formed  in  the  ultimate  process  of 
pulp  decomposition  as  will  be  explained  later  on  in  this  chapter. 
From  the  foregoing,  it  must  be  evident  that  it  is  necessary  to  search 


378       CAUSES    AND    TREATMENT    OF    DISCOLORATIONS    OF    TEETH. 

for  Other  colored  substances,  besides  black  ferrous  sulphid,  which 
are  possible  to  be  formed  in  the  process  of  pulp  decomposition  and 
which  are  capable  of  staining  the  tooth  structure. 

In  articles  which  the  author  read  before  the  Odontographic  Society 
of  Chicago  {Dental  Review,  June,  1901,  October,  1902),  a  theory 
was  advanced  which  explained  the  variety  of  colors  exhibited  in  dis- 
colored teeth,  and  while  some  criticism  has  been  offered  in  regard  to 
this  theory,  he  is  still  of  the  opinion,  that  it  presents  today  the  most 
rational  solution  of  this  question  from  both  the  chemical  and  clinical 
viewpoint. 

As  has  been  stated,  ammonia  is  not  only  a  constant  end-product, 
but  it  is  generated  in  far  greater  quantities  than  any  other  gas.  It  is 
well  known  that  ammonia  has  the  property  of  uniting  chemically 
with  water,  which  is  always  present  in  a  putrescent  root  canal,  form- 
ing ammonium  hydroxid,  NH3  -I-  H^O  =  NH^OH.  This  reagent 
will  act  upon  the  soluble  salts  of  iron,  in  both  the  ferrous  and  ferric 
forms,  producing  respectively,  ferrous  and  ferric  hydroxid,  Fe(0H)2, 
Fe,(OH)6.  Therefore,  it  is  not  only  possible,  but  quite  probable, 
that  the  atomic  iron  which  is  liberated  in  the  process  of  decomposition, 
from  the  hemoglobin  or  perhaps  intermediate  compounds  containing 
it,  unite  with  the  ammonium  hydroxid  present,  forming  the  hydroxid 
of  the  metal;  and  inasmuch  as  the  compounds  containing  the  iron 
are  organic  or  weak,  the  ferrous  hydroxid,  in  all  probability,  would  be 
produced.  Ferrous  hydroxid  is  a  white  compound  which  readily 
absorbs  oxygen  when  in  the  moist  state  and  exposed  to  air,  and  grad- 
ually changes  to  ferric  hydroxid,  a  reddish-brown  compound.  In 
this  change  there  is  an  array  of  four  distinct  colors — white,  green, 
black  and  brown — and  in  the  blending  of  these  four  colors  there  is 
produced  every  variety  of  shades  exhibited  in  discolored  teeth.  This 
seems  to  suggest  a  plausible  explanation  as  to  why  teeth  containing 
putrescent  pulps  change  color  when  air  is  admitted;  also  why  a  tooth 
containing  a  recently  decomposed  pulp  is  not  discolored  and  does 
not  readily  change  color  until  air  is  admitted.  I  fully  recognize  the 
fact  that  ferrous  hydroxid  is  not  the  only  compound  of  iron  capable 
of  producing  color  changes  when  moist  and  exposed  to  air.  Nearly 
all  of  the  ferrous  compounds  change  more  or  less;  but  with  the  possible 
exception  of  ferrous  carbonate,  which  could  be  formed,  ferrous  hy- 
droxid is  the  only  compound  of  iron  possible  to  be  produced,  the  color 
changes  of  which  correspond  to  those  seen  in  teeth  which  tiave  reached 
the  stage  of  permanent  discoloration. 

I  have  stated  in  this  chapter  that,  in  my  opinion,  it  was  also  possible 


GENERAL    CONSIDERATIONS.  379 

for  ferrous  sulphid  to  be  formed  ultimately  by  the  putrefactive  process; 
but  it  can  only  be  produced  by  the  hydrogen  sulphid  acting  first  upon 
the  ammonia,  forming  ammonium  sulphid,  H^S  +  2NH3  =  (NHJ,S. 
This  alkaline  reagent  will  act  upon  the  soluble  salts  of  iron,  precipi- 
tating the  metal  as  ferrous  sulphid.  My  conclusions,  then,  with 
reference  to  the  true  cause  of  the  discoloration,  are  these:  that  the 
permanent  yellow  discoloration  is  due  to  the  formation  of  ferric 
hydroxid ;  the  bluish-black  discoloration  to  a  mixture  of  ferric  hydroxid 
and  ferrous  sulphid — or  to  a  failure  of  the  ferrous  hydroxid  to  become 
completely  oxidized  into  the  ferric  form  owing  to  a  lack  of  moisture 
or  oxygen;  the  other  colors  observed  are  transitory  and  are  due  to  the 
gradual  transition  of  the  ferrous  into  the  ferric  hydroxid.  In  coming 
to  these  conclusions  I  have  accepted  the  statement  that  iron  plays 
the  most  important  role  of  all  the  elements  entering  into  the  discolor- 
ation problem;  for  if  it  were  possible  to  remove  the  hemoglobin  from 
the  blood  or  the  iron  from  the  hemoglobin,  I  do  not  believe  the  dentin 
could  be  discolored  by  any  compound  possible  to  be  formed  by  the 
process  of  pulp  decomposition.  If  this  be  true,  my  reasoning  is  at 
least  logical. 

Having  thus  far,  in  this  chapter,  discussed  the  cause  of  the  dis- 
coloration of  tooth  structure,  the  methods  of  restoring  the  normal 
color  will  now  be  considered. 

When  a  case  presents  for  bleaching  there  are  three  important 
things  to  be  determined: 

(i)  Ascertain,  if  possible,  the  cause  of  the  discoloration. 

(2)  Decide  whether  or  not  the  color  can  be  successfully  restored. 

(3)  The  selection  of  the  proper  bleaching  agent  with  which  to 
restore  the  color. 

The  general  cause  of  the  discoloration  can  usually  be  ascertained 
from  the  history  of  the  case  as  related  by  the  patient.  Whether  or 
not  the  tooth  can  be  successfully  bleached  depends  largely  upon  the 
cause  of  the  discoloration,  the  condition  of  the  tooth  structure,  and 
the  length  of  time  the  tooth  has  been  discolored.  Experience  will 
prove  that  the  teeth  which  will  permanently  retain  their  color,  after 
it  is  restored,  are  those  that  have  a  good  bulk  of  dentin  and  which 
dentin  can  be  protected  by  the  remaining  enamel  and  some  filling 
material,  preferably  porcelain  if  this  material  is  at  all  indicated.  I 
desire  to  emphasize  the  fact  that  it  is  folly  to  expect  a  tooth  to  retain 
its  color-  any  length  of  time  after  once  being  bleached  unless  ihe  dentin 
is  properly  protected. 

Having  ascertained  the  cause  of  the  discoloration  and  believing 


380       CAUSES    AND    TREATMENT    OF    DISCOLORATIONS    OF    TEETH, 

that  the  condition  of  the  tooth  structure  justifies  us  in  attempting  ta 
bleach  the  tooth,  we  come  to  the  most  important  consideration,  viz., 
the  selection  of  the  bleaching  agent,  with  which  the  color  can  be 
restored  with  the  least  inconvenience  to  the  patient  and  operator. 

Methods. — All  of  the  methods  employed  in  bleaching  teeth  involve 
more  or  less  chemistry;  and  from  a  chemical  viewpoint  there  are  two 
general  methods  of  bleaching  teeth — oxidation  and  reduction. 

I.  Oxidation  Method. — This  general  method  is  of  two  kinds  also 
direct  and  indirect. 

(i)  Direct. — By  direct  oxidation  is  meant  the  use  of  any  agent  or  agents 
from  which  oxygen  can  be  directly  obtained.  The  agents  used  for 
the  purpose  are: 

Sodium  dioxid,  NajO.^.  Twenty-five  per  cent  ethereal  solution  of 
hydrogen  dioxid.  HjOj.  Alphozone,  (COOH.  CHj.  CH^CO),- 
O2.  Aluminum  Chlorid,  AljCl^,  and  a  three  per  cent  aqueous 
solution  of  hydrogen  dioxid.     Oxalic  acid,  HjCjO^.  2H2O. 

(2)  Indirect. — By  indirect  oxidation  is  meant  the  use  of  any  agent  or 
agents  by  which  oxygen  can  be  obtained  indirectly.  The  agents 
employed  are  such  as  will  liberate  nascent  chlorin,  CI,  a  chemic- 
ally active  gas,  which,  in  the  presence  of  moisture  seizes  upon  a 
molecule  of  water,  HjO,  abstracts  the  atoms  of  hydrogen,  H, 
forming  hydrochloric  acid,  HCl,  and  liberates  the  oxygen,  O,  in  the 
nascent  state,  as  HjO  +  2C1=  2HCI  +  O  (nascent).  Some  of 
the  agents  used  for  this  purpose  are: 

Aluminum  chlorid  and  a  freshly  prepared  Labarraque's    solution 

(Harlan). 

Chlorinated  lime  and  dilute  acetic  acid  (Truman). 

Powdered  alum,  Al2K2(SOj4,  and  Labarraque's  solution. 

Solution  of  sodium  chlorid  electrically  decomposed. 

II.  Reduction. — By  reduction  is  meant  the  use  of  any  agent  or 
agents  which  will  abstract  oxygen  from  a  compound  containing  it. 
The  agents  which  have  been  recommended  are,  sodium  sulphite, 
Na^SOj,  10  parts,  and  boric  acid,  H3BO3,  7  parts.  These  are 
mixed  and  placed  within  the  tooth,  moistened  with  water  and  her- 
metically sealed.  (Kirk.)  A  reaction  occurs  between  the  two  sub- 
stances with  the  ultimate  formation  of  sulphurous  acid  which  has  a 
great  affinity  for  oxygen  and  is  therefore  a  good  reducing  agent.  In 
some  cases  where  the  tooth  has  been  discolored  by  remedial  agents 
and  where  it  is  desired  to  break  up  the  color  molecule,  good  results 
are  obtained  by  this  method.     Whenever  the  method  is  used  the 


GENERAL    CONSIDERATIONS.  381 

tooth  should  subsequently  be  thoroughly  washed  with  an  alkaline 
solution  such  as  a  ten  per  cent  solution  of  sodium  bicarbonate  or 
borax  to  neutralize  the  acid. 

In  most  cases  of  discoloration  the  direct  oxidation  method  is 
preferable  and  in  view  of  the  fact  that  all  of  the  agents  used  in  the 
direct  method  of  bleaching  depend  upon  the  generation  of  oxygen 
for  their  efficacy,  it  can  readily  be  understood  that  the  direct  method 
is  far  more  satisfactory.  The  fact,  also,  that  hydrochloric  acid  is  a 
constant  by-product  in  the  indirect  method,  thereby  creating  an  acid 
medium,  adds  to  the  objectionable  features  of  this  method;  for  manu- 
facturers have  recognized  for  years  that  better  results  can  be  obtained 
in  bleaching  ivory,  wool,  hair,  feathers,  etc.,  when  the  bleaching  process 
was  carried  on  in  an  alkaline  medium.  This  is  likewise  true  in  bleach- 
ing teeth.  Believing  then,  that  the  direct  oxidation  method  is  far 
superior  to  the  indirect,  I  shall  not  burden  my  readers  by  describing 
the  latter  method;  but  will  direct  attention  to  the  detailed  use  of  sodium 
dioxid — a  direct  oxidizing  agent  and  one  which,  if  its  chemical  prop- 
erties are  known  and  its  dental  application  understood,  the  author 
believes  to  be  the  best  agent  for  bleaching  teeth  thus  far  suggested  to 
the  profession. 

Sodium  dioxid  was  introduced  by  Dr.  Kirk  in  1893.  It  is  a  rare 
chemical,  not  because  it  is  difficult  to  manufacture,  but  because  of 
the  fact  that  in  the  past  there  has  been  little  demand  for  it.  Its 
chemical  activity  precludes  its  use  on  soft  tissue;  hence,  it  is  scarcely 
known  to  the  medical  profession,  and  is  not  kept  in  many  pharmacies. 
It  is  the  oxid  formed  when  sodium  is  allowed  to  burn  briskly  in  dry 
air  or  oxygen.  The  product  occurs  in  commerce  as  a  yellow  powder 
and  is  readily  decomposed  by  water  into  caustic  soda  and  oxygen. 
Because  of  this  latter  fact,  much  of  the  product  obtained  from  whole- 
sale druggists,  labeled  "sodium  dioxid,"  is  nothing  but  caustic  soda. 
This  accounts  for  the  fact  that  many  dentists  have  tried  this  method 
of  bleaching  and  failed  to  get  results.  The  fault  is  not  with  the  method, 
but  with  the  powder  used.  In  order  that  we  might  be  able  to  ascertain 
the  efficacy  of  the  chemical,  some  years  ago  I  devised  a  simple  chemical 
test  for  this  purpose.  In  a  clean,  dry  test  tube  place  about  one  gm. 
(15  grs.)  of  the  powder  and  to  it  add  i  or  2  c.  c.  (15  or  30  m.)  of  water. 
If  the  specimen  is  good  sodium  dioxid,  enough  oxygen  should  be 
generated  to  kindle  a  glowing  splinter  held  at  the  mouth  of  the  tube. 
Having  tested  the  chemical  and  proved  it  to  be  sodium  dioxid,  and  not 
caustic  soda,  the  next  thing  is  to  properly  prepare  the  tooth,  which, 
of  course,  should  have  been  previously  treated  and  the  root  filled  with 


382       CAUSES    AND    TREATMENT    OF    DISCOLORATIONS    OF   TEETH. 

gutta-percha.     The  rubber  dam  should  be  adjusted,  if  possible  without 
the  use  of  the  steel  clamp.     The  ligature  should  be  wrapped  twice 
around  each  tooth  included  in  the  dam,  which  should  be  at  least  two 
teeth  on  either  side  of  the  one  to  be  bleached.     This  will  prevent  the 
by-product,  caustic  soda,  from  getting  on  the  soft  tissue  and  destroying 
it.     The  lower  third  of  the  root  filling  should  now  be  removed  with  a 
good  sized  round  bur — it  being  necessary,  for  permanent  results,  to 
bleach  the  tooth  rootwise  as  far  as  possible.     We  are  now  ready  to 
apply  our  bleaching  agent.     Both  the  dry  sodium  dioxid  and  a  solution 
made  by  carefully  dusting  the  powder  into  ice  water  is  recommended 
to  be  used.     The  best  results  are  obtained  by  using  the  dry  powder, 
placing  it  into  the  cavity  and  with  a  platinum  broach  or  pointed  glass 
instrument,  work  the  powder  well  up  into  the  canal  from  which  the 
root  filling  has  been  removed.     Care  should  be  taken  not  to  use  steel 
instruments,  as  the  oxygen  will  attack  the  steel  forming  ferric  oxid 
and  therefore  we  may  get  into  the  tooth  the  pigment  we  are  trying  to 
remove.     In  some  cases  it  is  rather  difficult  to  place  the  powder  in  the 
cavity  without  getting  it  on  the  patient's  face  or  clothing.     To  over- 
come this  a  strip  of  unannealed  i.iooo  platinum  foil  can  be  placed 
between  the  discolored  and  adjacent  tooth,  letting  it  extend  above 
or  below  the  cutting  edge,  as  the  case  may  be,  when  white  base  plate 
gutta-percha  can  be  warmed  and  pressed  against  the  lingual  surfaces 
of  the  teeth  included  in  the  dam.     This  forms  a  pocket  on  the  labial 
side  into  which  the  powder  can  be  easily  placed,  using  a  little  gold  or 
platinum  spoon  or  spatula.     In  more  difficult  cases  a  paste  can  be 
made  of  the  powder  and  chloroform,  in  which  it  is  insoluble,  quickly 
packing  the  paste  into  the  cavity,  evaporating  the  chloroform,  leaving 
the  dry  powder  where  it  is  desired.     Distilled  water  is  now  dropped 
upon    the    powder,  causing  a  lively  effervescence  and  the  following 
reaction  takes  place:    Na^^O^    +   H2O    =  2NaOH    +    O    (nascent). 
This  nascent  oxygen  is  a  powerful  oxidizing  agent.     It  attacks  and 
rapidly  destroys  any  organic  matter  which  may  be  present  in  the 
tubular  structure  of  the  dentin.     It  also  thoroughly  bleaches  vegetable 
colors  and  acts  upon  any  iron  compounds  which  may  have  produced 
the  discoloration.     It  converts  ferric  hydroxid,  if  present,  into  ferric 
oxid — still   an  insoluble   compound.     If  ferrous  sulphid  is  present  in 
the  moist  state,  it  may  be  converted  into  ferrous  sulphate,  a  soluble 
salt;  but  in  the  presence  of  caustic  soda  it  would  be  reprecipitated  as 
ferrous  hydroxid,  which,  in  turn,  in  the  presence  of  oxygen,  is  at  once 
reconverted  into  ferric  oxid.     Therefore,  the  pigment  to  be  removed 
if  our  chemical  reasoning  is  correct  as  to  the  cause  of  the  discoloration 


GENERAL   CONSIDERATIONS.  383 

from  pulp  decomposition,  is  ferric  oxid,  an  insoluble  compound  and 
must  be  removed  mechanically  by  washing  the  tooth.  Its  removal  is 
facilitated  by  the  by-product,  caustic  soda,  acting  upon  any  fatty 
substances — fat  being  an  end-product  of  the  putrefaction  of  the  proteid 
material — which  may  be  present  in  the  tubuli.  The  result  of  this 
action  being  a  soluble  soap,  the  removal  of  which  by  washing,  aids, 
as  stated,  the  mechanical  removal  of  the  insoluble  pigment. 

It  is  my  opinion  that  the  ultimate  success  depends  quite  as  much 
upon  the  mechanical  removal  of  the  coloring  matter  as  upon  the 
chemical  destruction  of  it;  therefore,  the  necessity  for  thoroughly 
washing  the  tooth  after  each  application  of  the  bleaching  agent. 
Warm  distilled  water  should  be  used  in  a  strong  syringe,  letting  a 
moist  sponge  absorb  the  water.  The  cavity  is  now  dried,  the  color 
of  the  tooth  observed  and  the  process  repeated,  if  necessary.  Usually 
two  or  three  applications  are  sufficient.  If  the  color  is  not  readily 
restored,  the  dentin  can  be  saturated  with  a  two  per  cent  solution 
of  sulphuric  acid  which  can  now  enter  the  tubuli  and  chemically 
convert  the  oxids,  that  may  not  have  been  mechanically  or  other- 
wise removed  by  the  saponifying  and  washing  process,  into  sulphates. 
The  salts  produced  are  freely  soluble  and  can  readily  be  washed  out 
by  again  using  the  warm  water.  When  the  tooth  is  satisfactorily 
bleached,  a  paste  of  precipitated  calcium  phosphate  and  distilled 
water  can  be  placed  in  the  cavity,  packed  into  the  lower  third  of  the 
root  and  burnished,  with  a  warm  burnisher,  against  all  exposed  dentin. 
This  is  thoroughly  dried  by  burnishing,  the  excess  removed,  and  a 
light-colored,  quick-setting  cement  used  to  form  a  base  for  the  final 
filling  which  had  better  be  inserted  before  the  dam  is  removed. 

In  conclusion  I  desire  to  say  that  in  the  bleaching  of  teeth  we 
find  a  practical  application  of  the  science  of  chemistry  to  the  practice 
of  dentistry;  and  that  in  the  discoloration  of  tooth  structure  from  the 
various  sources  can  be  found  a  fruitful  field  for  further  investigation. 


CHAPTER   XXIV. 
THE  TREATMENT  OF  CHILDREN'S  TEETH. 

BY  C.  N.  JOHNSON,  M.  A.,  L.  D.S.,  D.  D.  S. 

This  subject  naturally  divides  itself  into  two  parts — the  man- 
agement of  the  child,  and  the  management  of  the  teeth.  Tempera- 
mentally, physically  and  nervously  there  is  so  much  difference  in 
children  that  to  ignore  this  factor  and  prescribe  a  set  method  of  practice 
for  all  cases  would  result  in  confusion,  failure  and  disaster. 

The  first  visit  of  a  child  to  the  dentist  is  usually  a  momentous 
occasion.  Sometimes  it  is  undertaken  with  the  direst  dread,  at 
others  with  the  most  eager  anticipations;  all  dependent  on  the  point 
of  view  given  the  child  by  the  parent.  The  dentist's  duty  is  to  study 
the  temperament  of  the  child  most  carefully,  and  he  should  not  con- 
tent himself  with  anything  short  of  obtaining  a  perfect  mastery  over 
the  child,  at  least  during  the  time  the  latter  is  in  his  office.  The 
means  to  be  employed  in  gaining  this  mastery  are  as  varied  as  are  the 
manifestations  of  juvenile  human  nature — probably  the  most  varied 
of  anything  in  psychological  study. 

The  chief  factor,  the  fundamental  basis  of  success  in  controlling 
children,  is  the  exhibition  of  extreme  kindness  and  the  cultivation 
of  infinite  patience.  Unless  a  dentist  can  bring  this  kind  of  an  attitude 
to  the  management  of  his  young  patients  he  would  better  not  attempt 
their  treatment.  And  yet  there  are  some  children  so  unruly  by 
nature  and  so  spoiled  by  false  training  at  home  that  to  obtain  com- 
mand over  them  in  the  dental  chair  the  operator  must  be  firm  with 
them  almost  to  sternness.  If  the  parent  has  no  control  over  the 
child,  as  is  sometimes  unfortunately  the  case,  then  the  dentist  should 
be  the  means  of  giving  the  child  what  is  probably  its  first  real  lesson 
in  discipline.  And  let  it  be  said  that  no  class  of  men,  not  even  medical 
practitioners,  are  placed  in  so  favorable  a  relationship  to  these  young 
patients  for  the  purpose  of  instilling  into  them  obedience  and  stability 
of  character  as  is  the  dentist,  and  if  the  members  of  our  profession 
would  only  rise  to  the  possibilities  of  their  opportunities  in  this  regard 
they  would  do  no  small  part  in  developing  true  manhood  and  woman- 
hood in  the  rising  generation.     To  bring  up  a  child  with  no  idea  of 

25  385 


386  THE    TREATMENT    OF    CHILDREN'S    TEETH. 

individual  responsibility,  to  foster  a  tendency  toward  avoiding  any 
duty  of  a  disagreeable  nature,  to  always  sprinkle  roses  for  the  child 
to  tread  upon,  is  weakening  in  its  effect  and  results  in  deterioration 
of  character  and  the  pitiable  failure  to  meet  the  emergencies  of  life 
as  they  inevitably  arise. 

A  discriminating  dentist  can  do  much  in  his  professional  relation- 
ship with  these  young  minds  to  develop  in  them  stamina  and  force 
of  character,  and  it  is  sometimes  the  case  that  the  first  real  experience 
of  facing  and  properly  meeting  an  issue  is  fought  out  in  the  dental 
chair.  To  be  successful  in  the  management  of  children  under  these 
trying  circumstances  a  dentist  must  be  a  rare  student  of  human  nature, 
and  he  should  early  learn  just  when  to  be  yielding  and  tender,  and 
when  to  be  firm  as  adamant.  But  Ifet  it  always  be  remembered  that 
under  no  circumstances,  however  trying  the  case  may  be,  should  he 
allow  himself  to  lose  his  own  self-control  and  display  temper  or  im- 
patience; and  whenever  it  has  been  necessary  to  be  firm  and  e\en 
severe,  he  should  invariably  soften  his  demeanor  by  the  utmost  kind- 
liness and  an  unmistakable  interest  in  the  little  patient's  welfare. 
To  gain  complete  control  of  a  child  who  previously  has  never  been 
controlled  by  any  one  is  no  mean  achievement,  and  the  sense  of 
satisfaction  in  the  good  attained  is  well  worth  all  the  eflfort  it  requires 
to  accomplish  it. 

One  feature  of  the  management  of  children  in  the  dental  office 
which  in  this  enlightened  age  of  child  study  would  seem  unneces- 
sary of  mention,  but  which  unfortunately  is  still  a  factor  in  some 
instances,  is  the  habit  of  deceiving  the  child  as  to  what  is  to  be  done. 
There  is  no  more  fatal  error,  no  more  disastrous  or  appalling  wrong, 
than  to  deliberately  deceive  a  child,  and  the  result  of  one  such  decep- 
tion can  never  be  fully  estimated.  To  the  dishonor  of  some  parents 
we  are  occasionally  asked  even  in  the  beginning  of  the  twentieth 
century  to  become  a  party  to  such  an  iniquitous  practice,  but  no 
dentist  of  any  self-respect  or  manhood  will  ever  enter  into  such  a 
conspiracy.  It  is  always  well,  of  course,  to  destroy  in  the  mind  of  the 
little  patient  any  sense  of  fear  by  making  as  light  as  possible  of  the 
probable  severity  of  the  operation,  and  by  the  utmost  tenderness  and 
gentleness  of  demeanor;  but  to  deliberately  assure  the  child  that  a 
certain  operation  will  not  hurt  in  the  least  w^hen  it  is  almost  certain 
to  hurt,  and  worse  than  this  to  pretend  to  be  applying  some  medicament 
to  a  tooth  and  then  suddenly  seize  it  with  the  forceps  and  extract  it 
is  a  monstrous  and  cruel  wrong. 

Ordinarily  the  first  visit  of  a  child  to  the  dental  office  should 


THE   TREATMENT    OF    CHILDREN'S    TEETH.  387 

be  SO  managed,  if  possible,  that  no  work  of  a  disagreeable  nature  is 
undertaken.  Mothers  should  be  instructed  to  bring  their  children 
early,  even  before  the  necessity  seems  apparent,  so  that  the  child 
forms  the  habit  of  having  the  teeth  examined  and  gets  acquainted 
with  the  dentist.  Thus,  when  fillings  have  to  be  made  the  ice  is 
already  broken  and  the  way  made  easier.  If  the  case  has  been  deferred 
till  toothache  occurs,  and  the  visit  is  one  of  necessity  for  relief,  the 
only  operative  procedure  undertaken  at  this  time  should  be  merely 
to  stop  the  pain.  A  sympathetic  and  personal  interest  should  be 
manifest  for  the  little  sufferer,  and  the  impression  formed  at  this 
first  visit  that  the  dentist  is  a  kind  hearted  gentleman  and  not  at  all 
to  be  feared.  When  once  confidence  is  attained  it  will  usually  be 
found  that  most  children  will  tolerate  any  necessary  discomfort  in 
having  their  teeth  cared  for  provided  their  pride  is  appealed  to  in 
the  proper  manner  and  they  are  upheld  as  little  men  and  little  women. 

But  the  dentist  should  have  a  care  not  to  overtax  the  courage 
of  a  delicate  child,  and  should  constantly  watch  with  the  keenest 
eye  for  signs  of  wavering  or  undue  nervous  tension  during  an  opera- 
tion. It  is  sometimes  better  to  do  temporary  work  and  retain  the 
confidence  of  the  child  than  to  always  attempt  permanent  operations- 
and  thereby  run  the  risk  of  creating  distrust  and  dread.  This  is 
particularly  true  of  operations  on  the  deciduous  teeth  where  the 
object  is  more  to  keep  them  comfortable  for  a  few  years  than  to  do- 
artistic  and  permanent  work. 

The  materials  for  filling  deciduous  teeth  are  limited  to  those- 
easy  of  insertion  and  not  too  exacting  in  their  requirements.  When. 
cavities  occur  in  the  proximal  surfaces  of  the  incisors  they  are  usually 
better  managed  with  oxyphosphate  of  zinc  than  with  anything  else.. 
They  are  ordinarily  shallow,  and  the  fact  that  they  are  frequently 
quite  sensitive  prevents  the  operator  from  giving  them  any  appreciable 
retentive  form.  Cement  can  therefore  be  used  when  nothing  else 
will  remain  in  place.  These  teeth  do  not  often  call  for  much  operative 
interference  owing  to  their  early  loss  to  make  way  for  the  permanent 
incisors,  but  with  the  deciduous  molars  the  case  is  different.  They 
remain  four  or  five  years  after  the  incisors  are  gone,  and  the  problem. 
of  saving  them  when  they  decay  is  sometimes  exceedingly  difficult. 
They  should  be  given  early  and  frequent  attention  when  the  mouth' 
is  susceptible  to  caries,  with  the  aim  always  of  checking  the  disease 
and  keeping  the  teeth  comfortable  for  mastication.  The  reason 
for  this  is  not  only  that  the  child  shall  be  enabled  to  properly  prepare 
the  food  for  digestion  during  these  early  years,  which  of  itself  is  very 


388  THE    TREATMENT    OF    CHILDREN'S    TEETH. 

important,  but  that  proper  habits  of  mastication  are  established  at 
this  impressionable  age.  If  the  deciduous  molars  are  allowed  to  decay 
and  become  sensitive  the  child  involuntarily  forms  the  habit  of  bolting 
the  food  without  proper  mastication,  and  this  habit  once  formed  is 
likely  to  persist  through  life.  There  are  many  people  today  who  do 
not  masticate  their  food  to  the  extent  which  their  present  masticating 
apparatus  would  warrant  simply  because  they  have  formed  the  bad 
habit  of  bolting  their  food  during  youth. 

Simple  cavities  in  the  occlusal  surfaces  of  these  teeth  are  not 
difficult  to  manage.  They  may  be  filled  with  oxyphosphate  of  zinc, 
oxyphosphate  of  copper,  pink  base-plate  gutta-percha  or  amalgam,  as 
is  indicated  in  the  individual  case.  Amalgam  is  more  reliable  than 
either  of  the  others  provided  a  proper  preparation  of  the  cavity  may 
be  made  and  it  does  not  reach  too  close  to  the  pulp,  but  sometimes 
we  are  obliged  to  temporize  with  cement  or  gutta-percha. 

The  most  difficult  problem  we  meet  in  the  management  of  de- 
ciduous teeth  is  to  properly  treat  cavities  occurring  in  the  proximal 
surfaces  of  the  molars.  There  are  several  factors  in  these  cases 
tending  to  make  them  troublesome  to  control.  They  are  usually 
sensitive,  making  them  difficult  of  proper  preparation  for  the  reten- 
tion of  amalgam,  which  is  the  only  permanent  material  we  have  for 
preserving  them.  Unless  fillings  are  reasonably  well  anchored  in 
these  cavities  they  are  likely  to  be  loosened  by  mastication,  and  if 
we  attempt  too  deep  anchorage  we  endanger  the  pulp.  In  fact 
these  teeth  do  not  usually  present  much  area  of  tooth  tissue  in 
which  to  form  a  cavity  and  it  takes  but  little  penetration  of  decay 
to  involve  the  pulp.  It  is  always  best  to  avoid  irritating  the  pulp 
if  possible,  and  to  this  end  it  is  frequently  advisable  to  use  some  other 
kind  of  material  than  metal  to  fill  them. 

Much  of  the  discomfort  experienced  by  children  in  mastication 
is  due  to  the  packing  of  food  in  the  interproximal  spaces  wherever 
decay  has  occurred  in  these  surfaces.  If  cement  is  used  it  very  rapidly 
wears  away  so  as  to  present  a  space  between  the  teeth  and  thus  invite 
a  lodgment  of  food.  Not  only  this  but  frequently  we  find  the  teeth 
drifting  slightly  apart  as  the  jaw  expands  preparatory  to  the  eruption 
of  the  permanent  teeth,  all  of  which  increases  the  difficulty.  In  cases 
where  amalgam  cannot  be  used  and  cement  is  unreliable  the  patient 
may  be  made  more  comfortable  with  gutta-percha  than  any  other 
material,  though  this  is,  of  course,  more  or  less  temporary  in  its  service. 

The  problem  is  greatly  complicated  where  two  cavities  face  each 
other,  and  in  some  instances  the  surest  method  of  making  the  teeth 


TREATMENT    OF    PERMANENT    TEETH    DURING    CHILDHOOD.        389 

serviceable  for  mastication  is  to  bridge  across  the  interproximal 
space  from  cavity  to  cavity  with  gutta-percha.  This  is  the  only 
material  by  which  two  cavities  may  be  joined  in  this  way  on  account 
of  the  individual  movement  of  the  teeth.  If  a  rigid  material  like 
cement  or  amalgam  is  used  the  filling  will  very  shortly  be  loosened 
from  one  cavity  or  the  other,  but  gutta-percha  being  more  or  less 
yielding  will  accommodate  itself  to  the  movement  of  the  teeth  with- 
out injury.  If  this  plan  is  followed  provision  must  be  made  to  pre- 
vent the  gutta-percha  from  being  forced  down  between  the  teeth 
in  the  interproximal  space,  and  this  may  be  accomplished  effectively 
by  placing  a  metal  guard  of  gold,  platinum,  or  German  silver  across 
the  interproximal  space  allowing  the  ends  to  rest  on  the  gingival 
walls  of  the  cavities  and  building  the  gutta-percha  over  it.  This 
protects  the  gum  most  perfectly  and  admits  of  serviceable  mastica- 
tion without  discomfort.  As  the  gutta-percha  is  worn  away  it  may 
be  renewed  from  time  to  time,  and  although  this  is  at  best  a  tem- 
porary operation  yet  it  is  in  some  of  these  troublesome  cases  the 
only  procedure  by  which  the  teeth  may  be  made  serviceable. 

In  pulpless  deciduous  molars  the  case  should  be  treated  in  the 
usual  way,  except  that  some  care  should  be  taken  not  to  introduce 
medicines  which  have  a  disagreeable  taste  or  odor.  It  is  always 
desirable  with  children  to  avoid  as  much  as  possible  anything  which 
tends  to  create  prejudice  against  having  dental  operations  performed, 
and  usually  these  deciduous  cases  may  be  brought  under  control  by 
the  use  of  the  essential  oils  which  are  less  objectionable  than  some  of 
the  more  powerful  antiseptics. 

TREATMENT  OF  THE  PERMANENT  TEETH  DURING  CHILDHOOD. 

From  the  time  the  permanent  teeth  begin  to  erupt  at  about  six  years 
of  age  till  the  deciduous  teeth  are  all  lost  and  replaced  by  permanent 
ones  at  about  twelve  the  care  of  the  erupting  teeth  is  a  very  important 
consideration,  and  in  mouths  where  there  is  great  susceptibility  to 
decay  of  the  teeth  the  problem  of  saving  the  permanent  ones  is  some- 
times perplexing. 

When  the  incisors  begin  to  decay  in  the  proximal  surfaces  shortly 
after  their  eruption  it  is  seldom  that  we  can  insert  permanent  fillings 
in  them  at  once.  It  is,  of  course,  better  if  this  can  be  done,  thus 
making  one  operation  sufficient  and  creating  in  the  mind  of  the  patient 
the  impression  that  dental  operations  are  effective  when  properly 
performed.  But  there  are  many  patients  who  lack  the  fortitude  at 
such  a  tender  age  to  go  through  the  necessary  tension  to  have  thorough 


390  THE   TREATMENT    OF    CHILDREN'S    TEETH. 

work  performed,  and  it  is  better  to  make  several  operations  on  the 
one  tooth  at  different  times  and  preserve  the  courage  of  the  child 
than  to  attempt  a  perfect  piece  of  work  at  the  outset  and  break  the 
spirit  of  the  patient,  thus  creating  a  dread  of  having  dental  work  done. 
But  let  it  be  borne  in  mind  that  just  so  soon  as  it  is  found  possible 
to  have  the  temporary  fillings  replaced  with  permanent  ones  this 
should  be  done.  In  these  susceptible  cases  the  teeth  can  never  be 
made  too  secure  against  decay  even  by  the  very  best  work  the  operator 
is  capable  of,  and  it  is  therefore  well  not  to  trust  to  temporary  work 
longer  than  necessary.  But  in  this  connection  it  should  be  said  that 
the  attempt  to  use  gold  before  the  child  is  sufficiently  under  control 
to  admit  of  doing  a  perfect  piece  of  work  will  as  certainly  lead  to 
failure  as  will  the  use  of  other  .materials  more  temporary  in  their  nature. 
We  must  have  a  good  technique  in  any  operation  calculated  to  be 
permanent  and  the  requirements  of  gold  in  this  respect  are  more 
exacting  than  for  any  other  filling.  In  some  instances  we  may  employ 
inlay  work  in  children's  teeth  before  they  will  tolerate  the  exactions 
of  gold  foil  filling  and  thus  obtain  a  better  result  than  by  the  use  of 
any  of  the  plastic  materials. 

Each  case  should  be  studied  carefully  with  the  idea  of  learning 
the  temperament  of  the  child  and  knowing  how  to  gain  such  control 
as  shall  permit  of  the  best  service.  The  practice  of  dentistry  in  its 
highest  attainment  is  a  constant  study  of  conditions,  conditions  of 
the  mind,  conditions  of  the  teeth,  conditions  of  the  surrounding 
parts — all  of  which  materially  affect  us  in  the  treatment  of  every 
case.  And  in  this  connection  there  is  no  other  one  thing  of  equal 
importance  in  the  ultimate  saving  of  the  teeth  and  the  maintenance 
of  a  healthy  mouth  than  the  establishment  during  these  early  years 
of  the  correct  principles  and  practice  of  oral  hygiene.  It  is  not  the 
province  of  the  present  chapter  to  go  fully  into  this  phase  of  the  ques- 
tion, but  it  should  be  said  in  passing  that  no  dentist  is  doing  his  full 
duty  to  the  rising  generation  who  fails  to  impress  upon  his  young 
patients  the  importance  of  properly  caring  for  the  teeth  and  gums, 
or  who  does  not  give  full  instructions  as  to  how  this  should  be  done. 
This  should  also  be  followed  by  a  constant  surveillance  to  see  that 
his  instructions  are  carried  out. 

A  very  necessary  consideration  in  the  treatment  of  children's 
teeth  is  to  watch  carefully  the  condition  of  the  first  permanent  molar. 
This  tooth  is  one  of  the  most  important  in  the  entire  arch.  It  is  the 
chief  standard  bearer  of  the  jaws  during  the  period  when  the  de- 
ciduous teeth  are  being  lost  and  the  other  permanent  teeth  are  coming 


TREATMENT    OF   PERMANENT    TEETH    DURING    CHILDHOOD.       391 

into  place,  and  if  lost  early  it  invariably  results  in  the  jaws  dropping 
closer  together  than  normal  which  detracts  materially  from  the  force 
of  character  of  the  face.  If  it  is  lost  subsequently  to  the  eruption  of 
the  second  permanent  molar  and  the  bicuspids  it  produces  a  tipping 
of  the  other  teeth  into  the  space  so  as  to  disarrange  the  occlusion. 
No  arch  is  ever  perfectly  normal  with  the  first  permanent  molar 
missing,  and  even  in  those  cases  where  the  space  has  entirely  closed 
by  the  approach  of  the  second  molar  and  bicuspid  and  where  the 
occlusion  seems  good  from  the  buccal  aspect  it  will  be  found  defective 
if  models  are  made  and  a  careful  examination  is  given  the  lingual 
aspect. 

In  view  of  its  early  eruption  it  is  peculiarly  susceptible  to  decay, 
and  should  therefore  be  watched  most  carefully  and  preserved  by 
filling.  Where  it  has  been  extensively  broken  down  by  caries  before 
it  comes  to  the  dentist  it  may  usually  be  restored  to  full  functional 
usefulness  by  the  inlay  method,  and  no  pains  should  be  spared  to 
place  it  in  a  condition  of  health  and  service. 

As  has  already  been  stated,  one  of  the  chief  functions  of  the  dentist 
in  his  treatment  of  children  is  to  educate  them  to  the  importance  of 
properly  caring  for  the  teeth,  and  in  respect  of  the  first  permanent 
molar  it  may  be  said  that  this  education  should  begin  with  the  parent 
before  the  child  is  of  responsible  age  so  that  the  frequent  error  of 
mistaking  this  tooth  for  a  deciduous  one  and  allowing  it  to  go  by 
default  should  not  be  committed.  Parents  should  be  instructed  to 
bring  their  children  to  the  dentist  not  later  than  the  third  or  fourth 
year,  and  then  the  cooperation  of  the  dentist,  the  parent  and  the  child 
should  result  in  every  individual  growing  up  with  a  good,  serviceable 
set  of  teeth. 


CHAPTER  XXV. 
LOCAL  ANESTHESIA. 

BY  HERMANN  PRINZ,  A.  M.,  M.  D.,  D.  D.  S.' 

History. — The  elimination  of  pain  during  surgical  operations 
is  inseparably  interwoven  with  the  history  of  the  human  race.  It 
has  always  been  the  aim  of  those  interested  in  the  cure  of  bodily 
ills  to  relieve  pain  in  some  empirical  manner.  The  efforts  to  solve 
the  riddle  of  painless  operations  were,  however,  seemingly  so  very 
futile  that  even  as  late  as  1832  Velpeau  was  led  to  express  his  pessi- 
mism as  follows:  "To  escape  pain  in  surgical  operation  is  a  chimera, 
which  we  are  not  permitted  to  look  for  in  our  time."  Little  did 
he  expect  that  he  stood  at  the  very  threshold  of  the  discovery  of  anes- 
thesia and  that  less  than  a  decade  later  the  "  nirvana"  of  painless  opera- 
tions would  be  an  accomplished  fact.  And  when  Dieffenbach,  in  1847, 
wrote  these  classical  words  regarding  the  use  of  ether  as  an  anes- 
thetic, "the  beautiful  dream,  to  eliminate  pain,  has  become  a  fact — 
pain,  the  highest  consciousness  of  our  earthly  existence,  its  clearest  con- 
ception of  the  imperfections  of  our  body,  it  has  to  bow  low  before  the 
powers  of  the  human  mind,"  the  world  at  large  awakened  to  the  fact 
that  pain  had  been  conquered. 

The  discovery  of  anesthesia  is  essentially  to  be  credited  to  the 
dental  and  medical  profession  of  the  United  States,  and  the  names 
of  Crawford  W.  Long,  Horace  Wells,  William  P.  G.  Morton  and  Charles 
F.  Jackson  are  inseparably  connected  with  it.  "If  America  has 
contributed  nothing  more  to  the  stock  of  human  happiness  than  anes- 
thetics, the  world  would  owe  her  an  everlasting  debt  of  gratitude," 
said  the  late  Samuel  D.  Gross,  the  eminent  surgeon,  who  had  ample 
opportunity  to  observe  in  his  own  operating  room  the  most  remarkable 
changes  that  followed  the  introduction  of  anesthetics. 

From  an  historical  viewpoint,  comparatively  few  important  methods 
for  the  purpose  of  locally  obtunding  pain  are  to  be  recorded  prior  to 
the  introduction  of  cocain.  The  compression  of  nerve  trunks  for  the 
abolition  of  pain  seems  to  be  of  an  old  and  unknown  origin,  which  was 

393 


394  LOCAL    ANESTHESIA. 

revived  by  Guy  du  Chauliac  and  Ambroise  Par6,  and  finally  found  a 
permanent  place  in  surgery  as  the  Esmarch  elastic  bandage.  Physic- 
ally reducing  the  temperature  of  a  part  of  the  body  by  the  application 
of  cold  was  instituted  much  later.  Bartholin  and  Severino  introduced 
this  method  in  the  middle  of  the  sixteenth  century.  It  became  a  lost 
art,  however,  until  John  Hunter,  of  London,  again  called  attention  to 
its  benefits  by  demonstrating  it  upon  animals,  and  Larray,  the  chief 
surgeonof  Napoleon's  army,  employed  it  for  amputating  purposes  (1807). 
James  Arnott,  in  1849,  utilized  a  freezing  mixture,  consisting  of  ice  and 
salt,  as  a  means  of  producing  local  anesthesia.  Through  the  efforts 
of  Sir  B.  W.  Richardson,  in  1866,  it  was  placed  on  a  rational  basis  by 
the  introduction  of  the  ether  spray.  The  various  narcotics  which  were 
employed  for  internal  purposes  were  also  made  use  of  as  local  applica- 
tions. Mandragora,  henbane,  aconite,  the  juice  of  the  poppy  head, 
and  many  other  analgesic  drugs  enjoyed  a  world-wide  reputation. 
There  is  probably  no  other  medicinal  plant  around  which  clusters  more 
mysterious  and  quaint  associations  than  Mandragora.  It  should  be 
remembered,  however,  that  mandrake,  or  mandragora  (atropa  mandra- 
gora) ,  must  not  be  confounded  with  American  mandrake,  or  May  apple 
(podophyllum  peltatum),  to  which  it  bears  no  relation. 

The  empirical  search  for  new  methods  and  means  pressed  the 
mysticism  of  the  electric  current  into  service,  opening  a  prolific  field 
to  the  charlatan,  which  even  to  this  day  has  not  lost  its  charm.  Rich- 
ardson's voltaic  narcotism  for  a  time  attracted  the  attention  of  the 
medical  and  dental  profession.  Its  inventor  claimed  "that  by  the 
action  of  a  galvanic  current,  passing  through  a  narcotic  solution,  held 
in  contact  with  the  part  to  be  operated  upon,  some  of  the  narcotic  sub- 
stance passed  much  more  rapidly  into  the  tissues  and  that  in  many 
instances  complete  local  anesthesia  was  in  this  way  produced  by 
solutions  which  are  entirely  inert  when  applied,  even  to  the  most  deli- 
cate tissue,  without  the  galvanic  current."  This  very  same  principle, 
discovered  by  Reuss  in  1807,  and  introduced  by  him  as  "electric 
endosmosis,"  or  as  "cataphoresis,"  by  E.  du  Bois-Raymond,  was 
"newly  discovered"  and  reintroduced  into  dentistry  about  a  decade 
ago.  In  cyclonic  fashion  it  swept  over  the  globe,  but  today  it  is  almost 
forgotten.  Electric  or  galvanic  anesthesia  was  suggested  as  far  back 
as  1851  by  A.  Hill,  of  Connecticut.  Francis,  in  1858,  recommended 
the  attachment  of  the  electric  current  to  the  well-insulated  handles  of 
the  forceps  for  the  painless  extraction  of  the  teeth,  and,  as  dental  de- 
pots offer  appliances  of  this  nature  for  sale,  it  seems  that  this  method  is 
still  in  vogue  with  some  operators.     According  to  Regner  and  Didsbury, 


LOCAL    ANESTHESIA.  395 

as  cited  by  Sauvez,  a  current  of  electricity  of  high  frequency,  when 
directed  toward  the  long  axis  of  a  tooth  for  a  shorter  or  longer  period 
previous  to  its  extraction  produces  insensibility  to  pain.  In  1880  Bon- 
will  suggested  his  method  of  "rapid  breathing  as  a  pain  obtunder," 
which  he  claimed  "produces  a  similar  effect  to  that  of  ether,  chloroform 
and  nitrous  oxid  gas  in  their  primary  stages."  In  the  early  days  of 
modern  dentistry  many  feeble  efforts  were  made  to  alleviate  pain 
during  trying  operations.  Chloroform,  alcohol,  ether,  aconite,  opium, 
the  essential  oils,  and  many  other  drugs  were  the  usual  means  that  were 
employed,  either  separately  or  as  compounds,  usually  under  fanciful 
names,  for  such  purposes.  Snape's  calorific  fluid,  composed  of  chloro- 
form, tincture  of  lemon  balm,  and  oil  of  cloves;  nabolis,  consisting  of  a 
glycerid  of  tannic  acid  and  a  small  quantity  of  chloral  hydrate;  Morton's 
letheon,  which  was  sulphuric  ether  mixed  with  aromatic  oils,  are  ex- 
amples of  proprietary  preparations  which  enjoyed  quite  a  reputation  in 
their  time.  In  1853  Alexander  Wood  introduced  a  method  of  general 
medication  by  means  of  hypodermic  injections,  and  a  few  years  later 
the  French  surgeon  Pravaz  modified  the  old  style  syringe  for  this  special 
purpose,  which  since  is  known  as  the  "Pravaz"  or  hypodermic  syringe. 
At  once  it  was  suggested  to  apply  such  drugs  as  morphine  or  tincture 
of  opium  for  the  purpose  of  producing  local  anesthesia.  The  results 
were  not  encouraging,  however,  until  cocain  was  advocated.  Cocain 
was  discovered  by  Neimann  in  1859,  but  it  required  twenty-five  years 
to  make  known  the  remarkable  anesthetic  properties  which  this  alkaloid 
possesses  when  appHed  in  the  ready  soluble  form  of  its  hydrochloric 
salt.  It  was  on  September  15th,  1884,  that  Carl  Koller,  of  Vienna,  pre- 
sented this  epoch-making  communication  at  the  Ophthalmologic  Con- 
gress at  Heidelberg,  in  which  he  demonstrated  the  effects  of  cocain  as  a 
local  anesthetic.  With  the  introduction  of  this  drug  into  therapeutics 
local  anesthesia  achieved  results  which  were  beyond  expectations,  and 
its  final  adoption  created  a  new  era  in  local  anesthesia. 

Means  of  Producing  Local  Anesthesia. — The  term  anesthesia 
(without  sensation),  which  was  suggested  in  1846  by  the  great  physician- 
litterateur,  Oliver  Wendell  Holmes,  to  Dr.  Morton,  is  usually  defined  as 
an  artificial  deprivation  of  all  sense  of  sensation,  while  the  mere  absence 
of  pain  is  referred  to  as  analgesia.  Correctly  speaking,  the  term  local 
anesthesia  is  partially  a  misnomer.  In  producing  local  anesthesia  we 
do  not  fully  comply  with  all  the  requirements  that  anesthesia  demands, 
because  a  part  of  the  sensorium — the  sense  of  touch  for  instance — is  not 
abolished.  The  term  local  anesthesia  has,  however,  acquired  such  uni- 
versal recognition  that  it  would  seem  unwise  to  recommend  a  change. 


396  LOCAL    ANESTHESIA. 

Anesthesia  may  be  artificially  produced  by  inhibiting  the  sensory 
nerve  fibers  at  their  central  end-organs  in  the  brain  or  at  their  peripheral 
end-organs  in  the  tissues,  thus  producing  general  and  local  anesthesia. 
Local  anesthesia  may  be  obtained  in  two  definite  ways.  We  may  in- 
hibit the  function  of  the  peripheral  nerves  in  a  circumscribed  area  of 
tissue,  and  we  refer  to  this  process  as  "terminal  anesthesia,"  while,  if 
we  block  the  conductivity  of  a  sensory  nerve  trunk  somewhere  between 
the  brain  and  the  periphery,  we  speak  of  it  as  "conductive  anesthesia." 
Conductive  anesthesia  may  be  produced  by  injecting  into  the  nerve 
trunk  proper — endoneural  injection — or  by  injecting  into  the  tissues 
surrounding  a  nerv^e  trunk — ^perineural  injection.  The  latter  form  is 
the  usual  method  pursued  when  conductive  anesthesia  for  dental  pur- 
poses is  indicated.  Specific  forms  of  local  anesthesia  may  also  be  pro- 
duced by  paralyzing  the  sensory  ganglia  in  the  brain  or  in  the  spinal 
cord;  these  methods  have,  however,  no  bearing  on  the  subject  under 
consideration. 

The  successful  practice  of  local  anesthesia  involves  the  carefully 
adjusted  co-operation  of  a  number  of  important  details,  each  one 
constituting  a  definite  factor  in  itself,  which,  when  neglected,  must 
necessarily  result  in  failure.  As  a  whole,  the  practice  of  local  anes- 
thesia by  the  hypodermic  method  represents  the  composite  of  the  follow- 
ing factors: 

1.  A  solution  of  active  ingredients  corresponding  to  the  physical 
and  physiologic  laws  which  govern  certain  functions  of  the  living  cell. 

2.  A  carefully  selected  hypodermic  armamentarium. 

3.  A  complete  mastery  of  the  technique. 

4.  A  proper  selection  of  the  correct  method  suitable  for  the  case  on 
hand. 

5.  Good  judgment  of  prevailing  conditions. 

Physiologic  Action  of  Anesthetics. — According  to  more  recent  thera- 
peutic conceptions,  it  is  generally  recognized  that  a  drug  or  combi- 
nation of  drugs  which  simultaneously  produce  local  anemia  and  inhibi- 
tion of  the  sensory  nerves  in  a  circumscribed  area  of  tissue  is  the  logical 
solution  of  the  question  of  local  anesthesia.  Certain  important  factors, 
however,  relative  to  the  physiologic  and  physical  action  of  the  solution 
employed  for  hypodermic  injection  upon  the  cell  govern  the  successful 
application  of  such  methods.  It  is  of  prime  importance,  therefore,  to 
comply  with  the  laws  regulating  the  absorption  of  injected  solutions — 
osmotic  pressure. 

If  we  separate  two  solutions  of  salt  of  different  concentration  by  a 
permeable  animal  membrane,  a  continuous  current  of  salt  and  water 


LOCAL    ANESTHESIA.  397 

results,  which  ceases  only  after  equalization  of  the  density  of  the  two 
liquids — that  is,  until  equal  osmotic  pressure  (according  to  the  Boyle- 
Van't  Hoff  law)  is  established.  The  current  passes  in  both  directions, 
drawing  salt  from  the  stronger  to  the  weaker  solution,  and  water  vice 
versa,  until  osmotic  equilibrium  is  obtained.  The  resultant  solutions 
are  termed,  according  to  De  Vries,  isotonic. 

Osmotic  pressure  is  a  physical  phenomenon  possessed  by  water 
and  all  aqueous  solutions,  and  is  dependent  on  the  number  of  molecules 
of  salt  present  in  the  solution  and  on  their  power  of  dissocia- 
tion. In  organized  nature  these  osmotic  interchanges  play  an  impor- 
tant role  in  regulating  the  tissue  fluids  of  both  animals  and  plants. 
In  the  animal  tissue  the  circulation  depends  principally  upon  the 
mechanical  force  exerted  by  the  heart.  The  life  of  the  cell  depends  on 
the  continuous  passage  of  these  fluids,  which  furnish  the  nutrient 
materials,  consisting  of  water,  salt  and  albumin.  These  chemicals  are 
normally  present  in  certain  definite  proportions.  The  membrane  of 
the  living  cell  is,  however,  only  semi-permeable — that  is,  the  cell  readily 
absorbs  distilled  water  when  surrounded  by  it.  The  cell  becomes 
macerated,  loses  its  normal  structure,  and  finally  dies.  If  on  the 
other  hand,  the  surrounding  fluid  be  a  highly  concentrated  salt  solu- 
tion, the  solution  absorbs  water  from  the  cell;  no  salt  molecules  enter 
into  the  cell  body  proper.  The  cell  shrinks,  and  finally  dies.  This 
process  of  cell  death  is,  in  general  pathology,  referred  to  as  necrobiosis. 
Another  important  factor  teaches  that  all  aqueous  solutions  that  are 
isotonic  possess  the  same  freezing  point — that  is,  all  solutions  possessing 
an  equal  freezing  point  are  equi-molecular,  and  possess  equal  osmotic 
pressure.  This  law  of  physical  chemistry  has  materially  simplified 
the  preparation  of  such  solutions.  The  freezing  point  of  human 
blood,  lymph,  serum,  etc.,  has  been  found  to  equal  approximately 
0.55  degrees  C,  which  in  turn  corresponds  to  a  0.9  per  cent  sodium 
chlorid  solution.  Such  a  solution  is  termed  a  physiologic  salt  solution. 
In  the  older  works  on  physiology  a  0.6  per  cent  sodium  chlorid  solution 
is  referred  to  as  a  physiologic  salt  solution,  and  corresponds  to  the  den- 
sity of  the  blood  of  the  frog.  A  slight  deviation  above  and  below  the 
normal  percentage  of  the  solid  constituents  is  permissible.  When 
physiologic  salt  solution  at  body  temperature  is  injected  into  the  loose 
connective  tissues  under  the  skin  in  moderate  quantities,  neither 
swelling  nor  shrinking  of  the  cell  occurs.  A  simple  wheal  is  formed, 
which  soon  disappears,  and,  as  no  irritation  results,  consequently 
no  appreciable  pain  is  felt.  Other  similar  bodies  that  are  equally 
soluble  in  water  act  in  the  same  manner,  with  the  exception  of  the 


39^  LOCAL    ANESTHESIA. 

salts  of  the  alkali  and  alkaline  earth  metals — ^as  potassium  or  sodium 
bromid.  The  latter  substances  produce  intense  physical  irritation, 
followed,  however,  by  prolonged  anesthesia,  and  in  consequence  are 
termed  by  Liebreich  painful  anesthetics.  If,  on  the  other  hand, 
simple  distilled  water  is  injected,  only  a  superficial  anesthesia  is 
produced;  the  injection  itself  is  very  painful,  and  acts  as  a  direct 
protoplasm  poison  by  maceration  of  the  cell  contents,  which  results 
in  the  death  of  the  cell.  If  distilled  water  approximately  at  a  ratio 
of  ten  drams  to  the  pound  of  body  weight  is  injected  into  dogs,  they 
will  succumb  in  a  short  time.  The  injection  of  higher  concentrated 
salt  solutions  produces  opposite  efifects;  water  is  removed  from  the 
tissues  with  more  or  less  pronounced  pain,  and  followed  by  superficial 
anesthesia.  The  red  blood  corpuscles  are  extremely  susceptible  to 
any  injected  fluid  which  is  not  isotonic  in  its  nature.  They  are  uni- 
versally destroyed  ^hemolysis)  by  the  injection  of  fluids  which  are  not 
represented  by  an  isotonic  salt  solution.  Severe  tissue  disturbances 
result,  which  may  terminate  in  necrosis.  Hypotonic  solutions — 
solutions  containing  less  than  0.9  per  cent  of  sodium  chlorid — cause 
swelling  of  the  tissue,  while  hypertonic  solutions — solutions  containing 
more  than  0.9  per  cent  of  sodium  chlorid — ^produce  shrinkage.  These 
manifestations  are  proportionately  the  more  intense  the  further  the 
solution  is  removed  from  the  freezing  point  of  the  blood.  Furthermore, 
hypotonic  as  well  as  hypertonic  solutions  require  much  more  time  for 
their  absorption  than  isotonic  solutions,  as  the  osmotic  pressure  has 
to  be  standardized  to  the  surrounding  fluids — that  is,  to  the  isotonic 
index  of  the  tissue  fluids.  Local  anemia,  or  ischemia — a  temporary 
constriction  of  circulation — ^prevents,  as  it  has  been  experimentally 
shown,  the  rapid  absorption  of  fluids  that  are  injected  into  the  affected 
area.  Retarded  absorption  of  the  injected  fluid,  holding  poisonous 
drugs  in  solution,  means  increased  action  of  these  poisonous  drugs 
within  the  injected  area.  Increased  action  denotes  increased  con- 
sumption of  the  poisoned  drugs,  and,  as  a  consequence,  there  is  less 
danger  from  general  absorption. 

The  more  important  means  applied  for  the  purpose  of  producing 
local  anemia  are: 

1.  The  Esmarch  elastic  bandage. 

2.  The  application  of  cold. 

3.  The  extract  of  the  suprarenal  capsule,  or  its  synthetic  sub- 
stitutes. Some  observers  have  maintained  that  local  anemia  produces 
anesthesia.  This  is  not,  however,  the  case,  as  it  is  merely  an  im- 
portant means  to  confine  the  injected  anesthetic  to  the  anemic  region, 


LOCAL    ANESTHESIA.  399 

and  thus  bring  about  an  increased  and  prolonged  action  of  the  drug. 
Consequently  the  concentration  of  the  anesthetic  solution  may  be  of 
a  lower  percentage,  which,  of  course,  lessens  the  danger  of  intoxication. 
For  plausible  reasons  the  Esmarch  elastic  bandage  cannot  be  made 
use  of  for  dental  operations. 

Physically  reducing  the  temperature  of  the  body  by  the  applica- 
tion of  cold  (ice  pack,  ice  and  salt  mixture,  cold  metals,  etc.)  was 
practised  by  the  older  surgeons.  James  Arnott,  in  1848,  suggested 
the  adoption  of  diminished  temperature  as  "a  safer  mode  than  any 
hitherto  in  use  of  producing  insensibility  in  surgical  operations,"  and 
Blundell,  in  1855,  advocated  ice  packs  and  salt  solutions  as  means  of 
producing  "local  anesthesia  by  congelation"  for  dental  purposes. 
Through  the  efforts  of  Sir  B,  W.  Richardson,  in  1866,  this  method  was 
placed  on  a  rational  basis  by  the  introduction  of  his  ether  spray.  To 
obtain  good  results,  a  pure  ether  (boiling  point  95°  C),  free  from 
water,  is  necessary.  Certain  other  hydrocarbons  possess  similar  prop- 
erties in  varying  degrees,  depending  on  their  individual  boiling  point. 
In  1867,  Rottenstein  called  attention  to  the  use  of  ethyl  chlorid  as  a 
refrigerating  agent,  and  Rhein,  in  1889,  introduced  methyl  chlorid  for 
the  same  purpose.  In  1891  Redard  reintroduced  ethyl  chlorid  as  a 
local  anesthetic,  which  since  has  become  known  by  many  trade  names 
as  antidolorine,  kelene,  narcotile,  etc. — and  mixtures  of  the  first  two 
in  various  proportions,  known  as  anestol,  anestile,  coryl,  methethyl, 
etc.,  are  extensively  used  in  minor  oral  and  general  surgery.  A  pure 
ethyl  chlorid  (boiling  point  55°  F.,  13°  C.)  is  best  suited  for  this  pur- 
pose, as  it  lowers  the  temperature  of  the  tissues  sufficiently  to  pro- 
duce a  short  superficial  anesthesia  in  a  few  minutes.  Too  rapid 
cooling  or  prolonged  freezing  by  methyl  chlorid  (boiling  point 
12°  F.,  24°  C),  or  the  various  mixtures  thereof,  produce  deeper 
anesthesia,  but  such  procedures  are  dangerous.  They  frequently 
cut  off  circulation  in  the  affected  parts  so  completely  as  to  produce 
sloughing  (necrosis).  Liquid  nitrous  oxid  gas,  hquid  or  solid  car- 
bonic acid  (recently  known  as  carbonic  acid  snow),  and  liquid  air, 
all  of  which  have  a  boiling  point  far  below  zero,  are  recommended 
for  similar  purposes,  but  they  require  cumbersome  apparatus  and 
are  extremely  dangerous. 

Ethyl  Chlorid  and  Its  Administration. — Ethyl  chlorid — ^Mono- 
chlore thane;  hydrochloric  ether,  CaHgCl.  "A  haloid  derivative,  pre- 
pared by  the  action  of  hydrochloric  acid  gas  on  absolute  alcohol." 
At  normal  temperature,  ethyl  chlorid  is  a  gas,  and  under  a  pressure 
of  two  atmospheres  it  condenses  to  a  colorless,  mobile,  very  volatile 


400  LOCAL    ANESTHESIA. 

liquid,  having  a  characteristic,  rather  agreeable,  odor  and  burning 
taste.  It  boils  at  about  55°  F.  (13°  C.)  and  is  very  inflammable, 
burning  with  a  smoky,  green-edged  flame.  It  is  stored  in  sealed 
glass  or  metal  tubes,  and  when  liberated  at  ordinary  room  tempera- 
ture (70°  F.,  21°  C.)  it  evaporates  at  once.  In  commerce  it  is  sup- 
plied in  plain  or  graduated  glass  tubes  of  from  3  to  60  grams  ca- 
pacity, or  stored  in  metallic  cylinders  holding  from  60  to  100  grams 
or  more.  To  remove  the  ethyl  chlorid  from  the  hermetically  sealed 
smaller  tubes,  the  neck  has  to  be  broken  off,  while  the  larger  glass 
and  metallic  tubes  are  provided  with  suitable  stoppers  of  various 
designs  to  allow  definite  amounts  of  the  liquid  to  be  released. 

Mode  of  application.  For  the  extraction  of  teeth,  immediate  re- 
moval of  the  pulp,  opening  of  abscesses,  and  other  minor  opera- 
tions about  the  oral  cavity,  the  tube  should  be  warmed  to  body  tem- 
perature, by  placing  it  in  heated  water,  and  its  capillary  end  should 
be  held  about  six  to  ten  inches  from  the  field  of  operations.  The 
distance  depends  on  the  size  of  the  orifice  of  the  nozzle,  and  complete 
va'porization  should  always  be  produced.  The  Gebauer  tube  is 
fitted  with  a  spray  nozzle,  which  shortens  the  distance  to  one  or  two 
inches,  and  is  especially  well  adapted  for  dental  purposes.  The 
stream  is  directed  upon  the  tissues  until  the  latter  are  covered  with  ice 
crystals  and  have  turned  white.  For  the  extraction  of  teeth  the  liquid 
should  be  projected  directly  upon  the  surface  of  the  gum  as  near  the 
apex  of  the  root  as  possible,  but  care  should  be  taken  to  protect  the 
crown  of  the  tooth  on  account  of  the  painful  action  of  cold  on  this 
part.  Tissues  to  be  anesthetized  should  first  be  dried  and  well  sur- 
rounded by  a  film  of  vaselin  or  glycerin,  and  protected  by  cotton  rolls 
and  napkins,  to  prevent  the  liquid  from  running  into  the  throat.  Let 
the  patient  breathe  through  the  nose.  Occasionally  light  forms  of 
general  anesthesia  are  induced  by  inhaling  the  vapor.  On  account 
of  the  difficulty  of  directing  the  stream  of  ethyl  chlorid  upon  the  tissues 
in  the  posterior  part  of  the  mouth,  it  is  not  successfully  applied  in  those 
regions.  The  intense  pain  produced  by  the  extreme  cold  prohibits 
its  use  in  pulpitus  and  acute  pericementitis.  To  anesthetize  the  second 
and  third  branch  of  the  fifth  nerve,  it  is  recommended  to  direct  the 
stream  of  ethyl  chlorid  upon  the  cheek  in  front  of  the  tragus  of  the  ear, 
but  the  author  has  not  seen  good  results  from  such  a  procedure.  Cau- 
tion should  be  exercised  in  using  ethyl  chlorid  near  an  open  flame 
or  in  conjunction  with  the  thermocautery,  as  severe  burns  have  re- 
sulted by  setting  the  inflammable  vapor  on  fire. 

Within  the  last  decade  the  active  principle  of  the  suprarenal  cap- 


LOCAL    ANESTHESIA,  40I 

sule  has  evoked  extensive  comments  in  therapeutic  literature.  It 
has  been  isolated  by  a  number  of  investigators  under  different  names, 
as  epinephrin  by  Abel  (1897),  suprarenin  by  Fuerth  (1898),  and 
adrenalin  by  Takamine  and  Aldrich  (1901).  Many  other  titles 
are  given  to  this  chemical — as  adnephrin,  adrin,  paranephrin,  su- 
prarenalin,  supracapsulin,  hemostasin,  etc.  The  United  States 
Pharmacopoeia  (eighth  revision)  has  not  as  yet  admitted  this  alka- 
loid to  its  pages,  and,  therefore,  whenever  we  refer  here  to  the  hydro- 
chloric salt  of  the  alkaloid  of  the  suprarenal  capsule,  we  speak  of  it 
as  adrenalin,  the  term  which  is  at  present  preferred  in  the  United 
States.  Adrenalin  is  a  grayish-white  powder,  slightly  alkaline  in 
reaction,  and  perfectly  stable  in  dry  form.  It  is  sparingly  soluble  in 
cold  and  more  soluble  in  hot  water,  is  insoluble  in  ether  or  alcohol, 
with  acids  it  readily  forms  soluble  salts.  The  preparation  that  is 
employed  mostly  for  therapeutic  purposes  is  a  solution  of  adrenalin 
hydrochlorid  in  a  i  to  1000  physiologic  salt  solution,  to  which  pre- 
servatives— as  small  quantities  of  chloretone,  thymol,  etc. — are  added. 
Adrenalin  solution  does  not  keep  well.  On  exposure  to  air,  and  espe- 
cially in  the  presence  of  even  minute  quantities  of  an  alkaH,  it  is  easily 
oxidized,  becoming  pink,  then  red,  and,  finally,  brown,  and  with  this 
change  of  color  its  physiologic  property  is  destroyed.  If  the  adrenalin 
solution  be  further  diluted,  it  becomes  practically  worthless  within 
a  few  days. 

When  adrenalin  is  injected  into  the  tissues,  even  in  extremely 
small  doses,  it  temporarily  raises  the  arterial  blood  pressure,  acting 
as  a  powerful  vasoconstrictor  by  stimulating  the  smooth  muscular 
coat  of  the  blood  vessels,  and  thus  produces  local  anemia.  Large 
doses  finally  reduce  the  blood  pressure,  and  heart  failure  results. 
The  respiration  at  first  quickly  increases,  but  slows  down  and,  finally, 
stops  with  expiration.  Its  action  is  largely  confined  to  the  smooth 
muscle  fibers  of  the  peripheral  vessels.  Adrenalin  is  destroyed  by 
the  living  tissue  cells,  the  body  ridding  itself  of  the  poison  in  some  un- 
known manner.  While  adrenalin  does  not  possess  local  anesthetic 
action,  it  increases  very  markedly  the  effect  of  certain  anesthetics  when 
combined  with  them.  Very  recently  it  has  been  shown  by  Esch  that 
adrenalin  possesses  a  specific  action  on  nerve  tissue,  viz. :  it  prepares 
the  latter  tissue  in  a  peculiar  way,  so  as  to  take  up  the  anesthetic  more 
readily.  Esch  compares  this  action  with  the  use  of  a  mordant  in  the 
dyeing  industry,  viz.:  to  "fix"  the  color.  These  observations  are  of 
vast  importance  in  connection  with  the  production  of  local  anesthesia. 
Carpenter,  Peters,  MoUer,  and  others  referred  to  the  use  of  adrenalin 
26 


402  LOCAL   ANESTHESIA. 

in  this  respect,  and,  finally,  Braun,  in  1902,  published  his  classic  re- 
searches, and  to  him  and  his  co-workers,  especially  Heinze  and  Lawen, 
belong  the  credit  of  establishing  a  rational  basis  for  the  production  of 
local  anesthesia.  It  is  claimed  that  secondary  hemorrhage  frequently 
occurs  after  the  anemia  produced  by  the  adrenalin  has  subsided,  and 
that  tissues  themselves  suffer  from  the  poisoning  effect  of  the  drugs, 
resulting  in  necrosis.  Such  results  are  produced  only  by  the  injec- 
tion of  too  large  quantities  of  the  drug,  which  by  their  deeper  action 
close  up  the  blood  vessels,  and,  if  the  tissues  are  too  long  deprived 
of  the  circulation,  we  are  able  to  understand  why  sloughing  may 
result.  Small  doses  of  adrenalin  have  no  effect  upon  the  tissues  or 
on  the  healing  of  a  wound.  Palpitation  of  the  heart  and  muscular 
tremor,  which  were  occasionally  noticed  in  the  early  period  of  the 
use  of  the  drug,  are  the  direct  result  of  too  large  doses.  Recently 
a  synthetic  adrenalin  has  been  successfully  prepared  by  Stolz,  which, 
with  hydrochloric  acid,  forms  a  stable  and  readily  soluble  salt.  It 
is  known  as  synthetic  suprarenin  hydrochlorid.  The  new  chemical 
has  been  carefully  tested  physiologically  and  in  clinical  work,  and  the 
general  consensus  of  opinion  points  to  the  fact  that  it  is  not  alone  equal, 
but  in  certain  respects  superior,  to  the  organo-preparations.  Syn- 
thetic suprarenin  solutions  may  be  readily  sterilized  by  boiling.  They 
are  relatively  stable,  and  their  chemic  purity  insures  uniform  results. 
They  are  comparatively  free  from  dangerous  side  actions.  The  writer's 
observations  regarding  the  value  of  synthetic  suprarenin  relative  to 
its  actions  and  its  general  behavior  is  in  full  accordance  with  the 
above  statements,  and  its  advantages  over  the  organo-preparations 
has  led  us  to  adapt  it  as  a  component  in  the  preparation  of  local  anes- 
thetic solutions.  For  dental  purposes — that  is,  for  injecting  into  the 
gum  tissue — the  dose  may  be  hmited  to  one  drop  of  the  adrenalin 
solution  (i  to  1000)  or  the  synthetic  suprarenin  solution  (i  to  1000), 
added  to  each  cubic  centimeter  of  the  anesthetic  solution,  five  drops 
being  approximately  the  maximum  dose  to  be  injected  at  one  time. 

Cocain  Hydrochlorid. — It  is  the  principal  alkaloid  obtained  from 
cocoa  leaves  (erythroxylon  coca)  a  large  shrub  indigenous  to  tropical 
South  America.  It  appears  in  colorless  crystals,  flaky,  lustrous 
leaflets  or  white  powder;  it  is  odorless,  has  a  saline,  slightly  bitter  taste 
and  produces  when  placed  upon  the  tongue  a  tingling  sensation  fol- 
lowed by  numbness.  At  ordinary  temperature  it  is  soluble  in  about 
one-half  part  of  water,  about  three  parts  of  alcohol  and  glycerin,  also 
soluble  in  chloroform,  ether  and  olive  oil.  Its  aqueous  solution  is 
neutral  to  litmus  paper.     Prolonged  heating  of  the  salt  or  its  solution 


LOCAL    ANESTHESIA.  403 

produces  decomposition  of  the  chemical  into  methyl  alcohol,  benzoic 
acid  and  ecgonin.  Solutions  of  cocain  are  unstable,  they  should 
preferably  always  be  made  fresh  when  wanted.  Cocain  hydrochlorid 
is  incompatible  with  alkali  hydrates  or  carbonates,  salicylates,  ben- 
zoates,  bromids,  and  iodids,  the  mercury  salts  and  silver  nitrate.  As 
early  as  i860,  Niemann  noted  the  fact  that  cocain  when  appHed  to 
the  tongue  produced  local  anesthesia;  later  investigations,  especially 
those  of  Von  Anrep  (1879)  were  not  fully  appreciated  until  Carl 
Koller,  of  Vienna,  later  of  New  York,  brought  it  before  the  medical 
profession  in  a  paper  read  before  the  Congress  of  Ophthalmologists 
at  Heidelberg  in  1884.  Cocain  is  a  general  protoplasmic  poison, 
possessing  a  selective  power  for  the  sensory  nerve  elements.  It 
paralyzes  the  nerve  cells,  fibers  and  endings  and  produces  vaso-con- 
striction  at  the  place  of  its  application.  The  respiration  is  at  first 
accelerated,  later  it  diminishes;  respiratory  paralysis  is  the  usual  cause 
of  death.  The  pulse  is  quickened,  later  it  is  slow  and  weak;  at  first, 
the  blood  pressure  rises,  then  falls  and  collapse  results.  Local  anes- 
thesia, according  to  Preyer's  conception,  is  produced  as  follows: 
Cocain  possesses  a  definite  affinity  for  the  living  protoplasm  of  the 
nerve  cell;  it  enters  with  it  into  a  labile  union,  thus  producing  local 
anesthesia,  which  lasts  until  this  temporary  union  is  broken  up  by 
releasing  the  chemical,  not  as  the  original  cocain,  however,  but  as  an 
inert  compound  of  a  simpler  structure.  In  other  words,  the  living 
tissues  rid  themselves  of  the  poison  in  some  unknown  manner.  In 
dead  tissue,  the  injected  cocain  will  suffer  no  change  whatsoever. 

No  direct  antidotes  of  cocain  are  known,  consequently  the  treat- 
ment of  general  intoxication  is  purely  symptomatic.  Recumbent 
position  of  the  body  and  inhalation  of  a  few  drops  of  amyl  nitrite  are 
the  first  important  steps  in  dealing  with  collapse,  which  should  be 
followed  in  severe  cases  with  an  injection  of  strychnin  sulphate,  1-30 
of  a  grain,  together  with  artificial  respiration. 

The  relative  toxicity  of  a  given  quantity  of  cocain  solution  depends 
upon  the  concentration  of  the  solution.  Reclus  and  others  have 
clearly  demonstrated  that  a  fixed  quantity  of  cocain  in  a  5  per  cent 
or  10  per  cent  solution  is  almost  equally  as  poisonous  as  five  times  of 
the  same  quantity  in  a  1-5  per  cent  solution.  From  the  extensive 
literature  on  the  subject,  we  are  safe  in  fixing  the  strength  of  the 
solution  for  dental  purposes  at  i  per  cent.  This  quantity  of  cocain 
raises  the  freezing  point  of  distilled  water  just  a  little  above  0.1°  C. 
To  obtain  an  isotonic  solution  corresponding  to  the  freezing  point  of  the 
blood,  0.8  per  cent  of  sodium  chlorid  must  be  added.     Having  just 


404  LOCAL    ANESTHESIA. 

prepared  a  cocain  solution  which  is  equal  to  the  blood  in  its  osmotic 
pressure  upon  the  cell  wall,  it  is  now  necessary  to  aid  the  slightly  vaso- 
constrictor power  of  the  drug  by  the  addition  of  a  moderate  quantity 
of  adrenalin.  As  stated  above,  one  drop  of  adrenalin  added  to  2  c.c.  of 
the  isotonic  cocain  solution  is  sufficient  to  produce  the  desired  effect. 
A  suitable  solution  for  dental  purposes  may  be  prepared  as  follows : 

Cocain  hydrochloric! S  grains 

Sodium  chlorid 4  grains 

Sterile  water i  fluid  ounce 

To  each  syringeful  (30  minims)  add  one  drop  of  adrenalin  chlorid 
solution,  when  used. 

Ever  since  the  introduction  of  cocain  into  materia  medica  for 
the  purpose  of  producing  local  anesthesia,  quite  a  number  of  sub- 
stitutes have  been  placed  before  the  profession,  for  which  superiority 
in  one  respect  or  another  is  claimed  over  the  original  cocain.  The 
more  prominent  members  of  this  group  are  tropacocain,  the  eucains, 
acoin,  nirvanin,  alypin,  stovain,  novocain,  and,  very  recently,  quinin 
and  urea  hydrochlorid.  None  of  these  compounds,  with  the  exception 
of  novocain  has  proved  satisfactory  for  the  purpose  in  view.  The 
classical  researches  of  Braun  have  established  certain  factors  which 
are  imperative  to  the  value  of  a  local  anesthetic.  These  factors  con- 
cern their  relationship  to  the  tissues  in  regard  to  their  toxicity,  irrita- 
tion, solubility  and  penetration,  and  to  the  toleration  of  adrenalin. 

There  is  no  need  at  this  moment  to  enter  into  a  discussion  of 
the  pharmacologic  action  of  the  drugs  usually  classified  as  local  anes- 
thetics. Let  it  suffice  to  state  how  the  above-mentioned  drugs  fulfil 
the  demands  of  Braun.  Tropacocain  is  less  poisonous,  but  also  less 
active  than  cocain,  it  completely  destroys  the  action  of  adrenalin;  the 
eucains  partially  destroy  the  adrenalin  action,  they  are,  comparatively 
speaking,  equally  as  poisonous  as  cocain;  acoin  is  irritating  to  the 
tissues  and  more  poisonous  than  cocain;  nirvanin  possesses  little 
anesthetic  value;  alypin  and  stovain  are  closely  related,  producing 
severe  pain  when  injected,  which  occasionally  has  resulted  in  necrosis. 
Quinin  and  urea  hydrochlorid  reacts  strongly  acid  and,  as  a  con- 
sequence, severely  damages  the  tissues  in  the  injected  area.  As  we 
have  recently  shown  elsewhere  it  possesses  no  advantage  when  employed 
as  a  local  anesthetic  in  dental  operations  but  has  many  disadvantages 
as  compared  to  cocain  or  novocain. 

Novocain  alone  fully  corresponds  to  every  one  of  the  above  claims. 
Its  toxicity  is  about  two  to  six  times  less  than  cocain;  it  does  not  irritate 
in  the  slightest  degree  when  injected,  consequently  no  pain  is  felt 


LOCAL    ANESTHESIA.  405 

from  its  injection  per  se;  it  is  soluble  in  its  own  weight  of  water;  it 
will  combine  with  adrenalin  in  any  proportion  without  interfering 
with  the  physiologic  action  of  the  latter,  and  it  will  be  readily  ab- 
sorbed by  the  mucous  membrane.  The  studies  of  Biberfield  and  Braun 
brought  to  light  another  extremely  interesting  factor  concerning  the 
novocain-adrenalin  combination.  Both  experimenters,  working  in- 
dependently of  each  other,  observed  that  the  adrenalin  anemia  on  the 
one  hand,  and  the  novocain  anesthesia  on  the  other  hand  were  markedly 
increased  in  their  total  effects  upon  the  tissues.  Consequently,  a  small 
quantity  of  this  most  happy  combination  is  required  to  produce  the 
same  therapeutic  effect  as  a  large  dose  of  each  individual  drug  alone 
would  produce  when  injected  separately.  The  injection  of  a  solution 
of  the  combined  drugs  is  precisely  confined  to  the  injected  area;  general 
effects  are,  therefore,  rarely  produced. 

Novocain  is  the  hydrochloric  salt  of  a  synthetically  prepared 
alkaloid,  the  methyl  ester  of  p-aminobenzoic  acid.  It  is  a  white 
crystalline  powder,  or  colorless  needle-shaped  crystals,  melting  at 
263°  F.  (156°  C).  It  may  be  heated  to  200°  F.  (120°  C.)  without 
decomposition.  It  dissolves  in  an  equal  amount  of  cold  water,  the 
solution  having  a  neutral  character;  in  cold  alcohol  it  dissolves  in  the 
proportion  of  i  to  30.  Caustic  alkalies  and  alkaline  carbonates  pre- 
cipitate the  free  base  from  the  aqueous  solution  in  the  form  of  a  color- 
less oil,  which  soon  solidifies.  It  is  incompatible  with  the  alkalies 
and  alkaline  carbonates,  with  picric  acid,  and  the  iodids.  Its  solu- 
tions may  be  sterilized  by  boiling  without  decomposition. 

As  stated  above,  the  relative  toxicity  of  a  given  quantity  of  cocain 
in  solution  depends  upon  its  concentration,  this  same  peculiarity 
is  not  shared  by  novocain.  The  dose  of  novocain  may  be  safely 
fixed  at  one-third  of  a  grain  for  a  single  injection.  For  dental  pur- 
poses a  one  and  one-half  or  a  two  per  cent  solution  in  combination 
with  adrenalin  has  been  injected  without  any  ill  results.  For  the  pur- 
pose of  confining  the  injected  novocain  to  a  given  area,  the  addition 
of  adrenalin  in  small  doses,  on  account  of  its  powerful  vasoconstrictor 
action,  is  well  adapted.  It  is  the  important  factor  which  prevents  the 
ready  absorption  of  both  drugs  and  consequently  largely  nullifies 
poisonous  results.  An  injection  of  ten  drops  of  a  two  per  cent  solu- 
tion of  novocain  labially  into  the  tissue  produces  a  diffuse  anesthesia 
lasting  approximately  twenty  minutes;  the  same  quantity,  with  the  addi- 
tion of  one  drop  of  adrenalin  chlorid  solution  increases  the  anesthetic 
period  to  over  one  hour,  and  localizes  the  effect  upon  the  injected  area. 


4o6  LOCAL    ANESTHESIA. 

A  suitable  solution  of  novocain  for  dental  purposes  may  be  pre- 
pared as  follows: 

Novocain lo  grains 

Sodium  chlorid 4  grains 

Distilled  water i  fluid  ounce 

Boil. 

To  each  syringeful  (2  c.c.)  add  two  drops  adrenalin  chlorid  solu- 
tion when  used. 

A  sterile  solution  may  be  made  extemporaneously  by  dissolving 
the  necessary  amount  of  novocain-adrenalin  in  tablet  form  in  a  given 
quantity  of  boiled  distilled  water.  A  suitable  tablet  may  be  prepared 
as  follows: 

Novocain 1-3  grain 

Synthetic  suprarenin  hydrochlorid 1-1200  grain 

Sodium  chlorid   1-3  grain 

One  tablet  dissolved  in  twenty  minims  of  sterile  water  makes 
a  two  per  cent  solution  of  novocain  ready  for  immediate  use. 

Solutions  for  hypodermic  purposes  should  preferably  be  made 
fresh  when  needed.  A  small  glass  dish  and  a  dropping  bottle  con- 
stitute the  simple  outfit  for  such  work.  The  dropping  bottle  should 
hold  from  one  to  two  ounces.  A  suitable  one  is  made  by  the  Whitall- 
Tatum  Co.,  of  Philadelphia,  and  may  be  bought  in  the  drug  shops. 
It  should  be  provided  with  a  dust  cap.  "A  groove  on  one  side  of  the 
neck  of  the  bottle,  and  a  vent  on  the  other,  connected  with  two  grooves 
in  the  back  of  the  stopper,  allow  the  contents  to  flow  out  drop  by  drop. 
A  quarter  turn  of  the  bottle  closes  the  bottle  tightly."  The  water  used 
for  making  the  solution  should  be  boiled  and  filtered  distilled  water. 
The  hypodermic  solution  can  be  made  extemporaneously  in  a  few  sec- 
onds; place  a  tablet  in  a  sterile  glass  dish,  add  20  minims  (i  c.c.)  of 
water,  and  to  facilitate  the  solution,  mash  the  tablet.  The  solution  is 
now  ready  for  immediate  use. 

The  Hypodermic  Armamentarium. — A  hypodermic  syringe  that 
answers  all  dental  purposes  equally  well  is  an  important  factor  in 
carrying  out  the  correct  technique  of  the  injection.  The  injection 
into  the  dense  gum  tissue  requires  from  15  to  50,  or  even  more,  pounds 
of  pressure  as  registered  by  an  interposed  dynamometer,  while  in 
pressure  anesthesia  100  or  more  pounds  are  frequently  applied. 

The  selection  of  a  suitable  hypodermic  syringe  is  largely  a  matter 
of  choice.  All-glass  syringes,  glass  barrel  syringes,  and  all-metal 
syringes  are  the  usual  types  found  in  the  depots.     After  testing  most 


LOCAL   ANESTHESIA.  407 

of  the  dental  hypodermic  syringes  offered  in  the  dental  depots  within 
the  last  five  years  by  means  of  the  pressure  gauge  and  in  clinical  work, 
subjecting  the  syringes  to  a  routine  wear  and  tear,  the  author  has  found 
that  the  all-metal  syringes  of  the  "imperial"  types  are  to  be  preferred 
over  other  makes.  They  are  usually  made  of  nickel-plated  brass,  which, 
however,  is  a  disadvantage,  as  the  nickel  readily  wears  off  from  the 
piston,  and  exposes  the  easily  corroded  brass.  The  Manhattan  all- 
metal  platinoid  syringe  gives  the  best  general  service,  and  we  can 
conscientiously  recommend  it  to  our  confreres.  The  syringe  holds  40 
minims  (2  c.c),  is  provided  with  a  strong  finger  cross-bar  and  is  ex- 
tremely simple  in  construction.  The  piston  consists  of  a  plain  metal  rod, 
without  a  thickened  or  ground  piston-end  or  packing.  The  piston-rod 
is  sufficiently  long  to  allow  about  two  inches  of  space  between  the  cross- 
bar and  the  piston-top.  This  space  is  of  importance,  as  it  allows  the  last 
drop  of  the  fluid  to  be  expelled  under  heavy  pressure  without  tiring  the 
fingers.  The  packing  consists  of  leather  washers  inserted  at  the  screw 
point,  and  are  quickly  removed  and  replaced  if  necessary. 

The  hypodermic  syringe  requires  careful  attention.  It  is  not 
necessary  to  sterilize  it  by  boiling  after  each  use,  unless  it  be  con- 
taminated with  blood  or  pus.  The  simple  repeated  washings  with 
alcohol  and  carefully  drying  is  sufficient.  The  cap  is  readjusted, 
and  the  piston-rod  is  covered  with  a  thin  film  of  carbonated  vase- 
lin,  or  surgical  lubricating  jelly,  and  placed  in  position.  If  the 
syringe  is  boiled,  all  the  washers  must  be  removed.  The  syringe 
is  kept  in  a  covered  glass  or  metal  case,  and  a  large  bacteriologic 
Petri  dish  is  suitable  for  this  purpose.  Leather-lined  or  felt-lined 
boxes  afford  breeding  places  for  bacteria.  Some  operators  prefer 
to  constantly  keep  their  syringes  in  an  antiseptic  solution  when  not 
in  use,  and  others  prefer  to  place  them  in  a  special  sterilizing  bottle, 
which  bottles  may  now  be  purchased  at  dental  depots. 

Dental  hypodermic  needles  should  be  made  preferably  of  seam- 
less steel,  or,  still  better,  of  nickel  steel,  26  to  28  B.  &  S.  gauge,  and 
provided  with  a  short  razor  edge  point.  Thicker  needles  cause  un- 
necessary pain,  and  thinner  needles  are  liable  to  break.  Iridio- 
platinum  needles  are  preferried  by  some  operators,  as  they  may  be 
readily  sterilized  in  an  open  flame.  The  needle  should  measure 
from  a  quarter  to  half  an  inch.  For  infiltration  anesthesia  one-inch 
needles  are  necessary,  and  curved  needles  of  various  shapes  are  essen- 
tial in  reaching  the  posterior  part  of  the  mouth.  The  "Schimmel" 
needles  are  excellent,  but  do  not,  however,  fit  every  syringe.  For 
pressure  anesthesia  special  needles  are  required,  and  may  be  bought 


408  LOCAL   ANESTHESL\. 

at  the  depots,  or  quickly  prepared  by  grinding  off  the  steel  needle  at 
its  point  of  reinforcement.  The  sterile  needles  should  be  kept  in  well- 
protected  glass  containers.  The  needles  are  sterilized  after  each  use 
by  boiling  in  plain  water,  dried  with  the  hot-air  syringe,  and  immedi- 
ately transferred  to  a  covered  sterile  glass  dish.  The  sterile  needles 
should  not  be  again  touched  with  the  fingers,  and  the  customary  wire 
insertion  is  unnecessary. 

Technique  of  Injection. — Various  methods  of  injecting  the  anes- 
thetic solution  about  the  teeth  are  in  vogue.  For  the  sake  of  con- 
venience we  may  be  permitted  to  divide  them  as  follows : 

The  subperiosteal  injection. 

The  peridental  injection. 

The  intraosseous  injection. 

The  perineurial  injection. 

The  injection  into  the  pulp. 

Before  starting  any  surgical  interference  in  the  mouth,  the  field 
of  operation  should  be  thoroughly  cleansed  with  an  antiseptic  solu- 
tion. A  thin  coat  of  the  official  tincture  of  iodin  painted  over  the 
surface  is  very  useful  for  this  purpose.  After  the  diagnosis  is  made 
the  method  of  injection  best  suited  for  the  case  on  hand  is  then  decided. 
The  necessary  quantity  and  the  concentration  of  the  anesthetic  solu- 
tion is  now  prepared,  and  the  syringe  and  hypodermic  needle  fitted 
ready  for  the  work.  To  facilitate  the  ready  penetration  of  the  needle 
into  the  tissues,  its  point  may  be  coated  with  carbolated  vaselin.  The 
correct  position  of  the  syringe  in  the  hands  of  the  operator  and  its 
proper  manipulation  is  an  important  factor,  and  has  to  be  acquired  by 
practice.  The  hand  holding  the  syringe  is  exclusively  governed  in  its 
movements  by  the  wrist,  so  as  to  allow  delicate  and  steady  move- 
ments, and  the  fingers  must  be  trained  to  a  highly  developed  sense  of 
touch.  The  syringe  is  filled  by  drawing  the  solution  up  into  it;  it  is 
held  perpendicularly,  point  up,  and  the  piston  is  pushed  until  the  first 
drop  appears  at  the  needle  point,  which  precaution  prevents  the  in- 
jection of  air  into  the  tissues. 

The  Subperiosteal  Injection. — The  subperiosteal  injection  about  the 
root  of  an  anterior  tooth  is  best  started  by  inserting  the  needle  midway 
between  the  gingival  margin  and  the  approximate  location  of  the  apex. 
The  pain  of  the  first  puncture  may  be  obviated  by  a  fine,  very  sharp 
pointed  needle,  the  simple  compression  of  the  gum  tissue  with  the  finger 
tip,  by  holding  a  pledget  of  cotton  saturated  with  the  prepared  anes- 
thetic solution  on  the  gum  tissue  for  a  few  moments,  or  by  applying 
a  very  small  drop  of  liquid  phenol  on  the  point  of  puncture.     The 


LOCAL    ANESTHESIA.  409 

needle  opening  faces  the  bone,  the  S}Tinge  is  held  in  the  right  hand, 
at  an  acute  angle  with  the  long  axis  of  the  tooth,  while  the  left  hand 
holds  the  lip  and  cheek  out  of  the  way.  After  puncturing  the  mucosa, 
a  drop  of  the  liquid  is  at  once  deposited  in  the  tissue,  and  the  further 
injection  is  painless.  Slowly  and  steadily  the  needle  is  forced  through 
the  gum  tissue  and  periosteum  along  the  alveolar  bone  toward  the 
apex  of  the  tooth,  depositing  the  liquid  under  pressure  close  to  the  bone 
on  its  upward  and  return  trip.  The  continuous  slow  moving  of  the 
needle  prevents  injecting  into  a  vein.  A  second  injection  may  be 
made  by  partially  withdrawing  the  needle  from  the  puncture  and 
swinging  the  syringe  anteriorly  or  posteriorly,  as  the  case  may  be, 
from  the  first  route  of  the  injection.  This  latter  method  is  especially 
indicated  in  injecting  the  upper  molars.  After  removing  the  needle, 
place  the  finger  tip  over  the  puncture  and  slightly  massage  the  injected 
area.  A  circular  elevation  outlines  the  injected  field.  The  naturally 
pink  color  of  the  gum  will  shortly  change  to  a  white  anemic  hue,  indi- 
cating the  physiologic  action  of  the  adrenalin  on  the  circulation. 
No  wheal  should  be  raised  by  the  fluid,  as  that  would  indicate  super- 
ficial infiltration  and  consequently  failure  of  the  anesthetic. 

As  the  hquid  requires  a  definite  length  of  time  to  pass  through 
the  bone  lamina  and  to  reach  the  nerv^es  of  the  peridental  membrane 
and  the  pulp,  from  five  to  ten  minutes  should  be  allowed  before  the 
extraction  is  started.  The  length  of  time  depends  on  the  density 
of  the  surrounding  structure  of  the  tooth.  The  progress  of  the  anes- 
thesia may  be  tested  with  a  fine  pointed  probe,  and  its  completeness 
indicates  the  time  when  the  extraction  should  be  started. 

The  upper  eight  anterior  teeth  usually  require  a  labial  injection 
only,  while  the  molars  require  both  a  buccal  and  a  palatine  injection, 
using  a  slightly  curved  needle  for  this  purpose.  Buccally  the  injec- 
tion is  made  midway  between  the  mesial  and  distal  root,  and  on  the 
palatine  side  over  the  palatine  root. 

The  lower  eight  anterior  teeth  are  comparatively  easily  reached 
by  the  injection.  The  straight  needle  is  inserted  near  the  apex  of 
the  tooth,  the  syringe  is  held  in  a  more  horizontal  position  and  the 
injection  proceeds  now  as  outlined  above. 

The  lower  molars  require  a  buccal  and  lingual  injection.  The 
curved  needle  is  inserted  midway  between  the  roots,  the  gum 
margin,  and  the  apices.  The  external  and  internal  oblique  lines 
materially  hinder  the  ready  penetration  of  the  injected  fluid,  and 
therefore  ample  time  should  be  allowed  for  its  absorption. 

If  two  or  more  adjacent  teeth  are  to  be  removed,  the  injection 


4IO  LOCAL    ANESTHESIA. 

by  means  of  infiltrating  the  area  of  the  gum  fold  directly  over  the 
apices  of  the  teeth  is  to  be  preferred.  It  is  advisable  to  use  a 
one-inch  needle  for  this  purpose,  holding  the  syringe  in  a  horizontal 
position,  so  as  to  reach  a  larger  field  with  a  single  injection. 

The  injection  into  inflamed  tissue,  into  an  abscess,  and  into  phleg- 
monous infiltration  about  the  teeth  is  to  be  avoided.  The  injection 
into  engorged  tissue  is  very  painful;  the  dilated  vessels  quickly  absorb 
cocain  without  producing  a  complete  anesthesia,  and  generally  poison- 
ing may  be  the  result.  In  purulent  conditions  the  injection  is  decidedly 
dangerous,  as  it  forces  the  infection  beyond  the  line  of  demarcation. 
If  the  abscess  presents  a  definite  outline,  the  injection  has  to  be  made 
into  the  sound  tissue  surrounding  the  focus  of  infiltration.  If  a  tooth 
is  affected  with  acute  diffuse  or  purulent  pericementitis,  a  distal  and  a 
mesial  injection  usually  produce  successful  anesthesia  by  blocking  the 
sensory  nerve  fibers  in  all  directions. 

Peridental  Anesthesia. — The  teeth  or  roots  standing  singly,  or 
teeth  affected  by  pyorrhea  or  similar  chronic  peridental  disturbances, 
are  frequently  quickly  and  satisfactorily  anesthetized  by  injecting  the 
fluid  directly  into  the  peridental  membrane.  This  method  is  known 
as  peridental  anesthesia,  and  its  technique  is  very  simple.  In  single- 
rooted  teeth  a  fine  and  short  hypodermic  needle  is  inserted  under  the 
free  margin  of  the  gum  or  through  the  interdental  papilla,  into  the 
peridental  membrane  between  the  tooth  and  the  alveolar  wall.  Some- 
times the  needle  may  be  forced  through  the  thin  alveolar  bone  so  as  to 
reach  the  peridental  membrane  direct.  To  gain  access  to  this  mem- 
brane in  teeth  set  close  together,  separation  is  essential.  It  may  be 
accomplished  with  an  orange  wood  stick  or  by  any  of  the  various 
mechanical  separators.  By  so  doing,  the  body  of  the  tooth  is  shifted 
to  one  side  and  thereby  creating  a  slight  space  between  it  and  the 
alveolar  process.  The  injection  is  now  made  directly  into  the  exposed 
peridental  membrane.  By  reversing  the  separator,  the  tooth  is  shifted 
to  the  opposite  side  and  the  injected  liquid  is  forced  toward  the  apex 
of  the  tooth.  A  second  injection  is  now  made  in  this  freshly  exposed 
portion  of  the  peridental  membrane.  Two,  sometimes  three,  in- 
jections are  necessary.  To  force  the  liquid  into  the  membrane  usu- 
ally requires  a  higher  pressure  than  that  which  is  necessary  for  inject- 
ing into  the  periosteum  covering  the  alveolar  process,  but  the  quantity 
of  the  anesthetic  fluid  is  less  than  that  which  is  required  for  the  former 
injection.  Acute  inflammatory  conditions  of  the  peridental  membrane 
and  its  sequelae  prohibit  the  use  of  this  method.  Peridental  anes- 
thesia is  the  purest  form  of  local  anesthesia,  since  the  seat  of  the 


LOCAL    ANESTHESLA..  41I 

nerve  supply  of  the  tooth  is  very  quickly  reached,  and  as  a  conse- 
quence the  results  obtained  are  in  the  majority  of  cases  extremely 
satisfactory,  provided  that  general  conditions  justify  its  applica- 
tion. The  method  is  especially  serviceable  for  the  removal  of  pulps 
and  in  all  cases  where  contact  anesthesia  is  not  indicated  or  for 
temporary  desensitizing  a  tooth  for  operative  procedures. 

Intraosseous  Injection. — To  facilitate  the  passage  of  the  injected 
fluid  into  the  bone  structure  proper,  Otte,  in  1896,  recommended  a 
method  by  which  he  forces  the  anesthetic  solution  directly  into  the 
spongy  cancelloid  bone.  Otte  terms  this  procedure  the  intraosseous 
method  of  injection,  and  its  technique  is  described  by  him  as  follows: 
After  the  gum  tissue  is  thoroughly  cleansed  with  an  antiseptic  solution, 
it  is  anesthetized  about  the  neck  of  the  tooth  in  the  usual  manner. 
After  waiting  two  or  three  minutes,  an  opening  is  made  into  the  gum 
tissue  and  the  bone  on  the  buccal  side  with  a  fine  spear  drill  or  a  Gates- 
Glidden  drill.  The  opening  should  be  made  more  or  less  at  a  right 
angle  with  the  long  axis  of  the  tooth,  a  little  below  the  apical  foramen  in 
single-rooted  teeth  or  between  the  bifurcation  in  the  molars.  The  right- 
angle  hand  piece  is  preferably  employed  for  this  purpose.  The  drill 
should  be  of  the  same  diameter  as  the  hypodermic  needle.  The 
gum  fold  is  tightly  stretched  to  avoid  laceration  from  the  rapidly  re- 
volving drill.  As  soon  as  the  alveolar  process  is  penetrated,  a  peculiar 
sensation  conveyed  to  the  guiding  hand  indicates  that  the  alveolus 
proper  is  reached,  and  the  sensation  felt  by  the  hand  is  about  the 
same  as  that  experienced  when  a  burr  enters  into  the  pulp  chamber. 
In  this  artificial  canal  the  close  fitting  curved  needle  of  the  hypo- 
dermic syringe  is  nov/  inserted,  and  the  injection  is  made  in  the  ordi- 
nary way.  The  quantity  of  fluid  used  is  much  less  than  is  usually 
needed  for  a  subperiosteal  injection.  The  roots  of  the  teeth  are  im- 
bedded in  a  sieve-like  mass  of  bone  tissue  (diploe),  which  allows  a 
ready  penetration  of  fluid  when  injected  under  pressure.  Very  re- 
cently, Masselink  advocates  this  method  of  the  anesthetization  of  any 
tooth  in  the  mouth  either  for  the  purpose  of  extracting  or  the  removal 
of  its  pulp.  He  employs  a  No.  1/2  round  burr  for  penetrating  the 
alveolar  plate  and  a  very  short  needle  (about  1/16  of  an  inch)  with  a 
dull  point  for  the  injection. 

Perineiirial  Injection. — For  the  anesthetization  of  a  number  of 
teeth  in  the  upper  or  the  lower  jaw,  conductive  anesthesia  by  means 
of  perineurial  injection  is  preferably  employed.  The  perineuria! 
injection  is  made  near  the  point  of  exit  or  entrance  of  the  various 
nerves  about  their  respective  foramina.     To  anesthetize  all  the  teeth 


412  LOCAL    ANESTHESIA. 

of  one-half  of  the  upper  jaw  four  injections  are  necessary,  i.  e.,  two 
buccally  and  two  on  the  palatine  side  of  the  bone.  A  one-inch  needle 
is  required  for  such  work.  To  reach  the  many  small  branches  of  the 
posterior  dental  nerves  at  the  alveolar  foramina  the  injection  is  made 
buccally  over  the  region  of  the  tuberosity  about  one  half  inch  above 
the  gingival  line  between  the  first  and  second  molar  tooth.  The  second 
injection  is  made  below  the  infraorbital  foramen,  so  as  to  reach  the 
middle  and  anterior  dental  nen^es.  With  the  index  finger  of  the  left 
hand  the  foramen  is  approximately  located  by  exerting  pressure  upon 
the  nerve-exit.  The  lip  is  lifted  up  with  the  middle  finger  of  the  same 
hand  and  the  needle  is  now  inserted  between  the  apices  of  the  cuspid 
and  first  bicuspid  teeth.  The  needle  is  slowly  pushed  forward  until 
its  point  is  felt  beneath  the  finger  tip.  To  reach  the  nerve  supply  of 
the  hard  palate  one  injection  is  made  near  the  posterior  palatine  canal, 
and  the  other  near  the  foramina  of  Scarpa.  The  great  palatine  nerves 
pass  through  the  posterior  palatine  canals  on  either  side  of  the  hard 
palate.  The  canals  lie  about  three-eighths  of  an  inch  above  the  edge  of 
the  alveolar  process  and  the  last  molar  tooth.  They  move  posteriorly 
with  the  eruption  of  the  successive  teeth.  The  naso-palatine  nerves 
pass  through  the  foramina  of  Scarpa  (incisive  foramen)  which  are 
situated  in  the  line  of  the  suture  of  the  maxillary  bones.  If  an  imagi- 
nary line  is  drawn  from  the  distal  borders  of  the  two  cuspids  and 
passing  over  the  hard  palate,  the  line  will  ordinarily  pass  through  the 
foramina.  The  needle  should  be  inserted  directly  back  of  the  papilla, 
which  lies  posteriorly  between  the  central  incisor  teeth. 

To  anesthetize  one-half  of  the  mandible,  three  injections  for 
the  deposition  of  the  anesthetic  solution  are  necessary.  The  first 
injection  is  applied  near  the  mandibular  foramen,  the  second  near 
the  mental  foramen,  and  the  third  into  the  incisive  fossa.  To  locate 
the  mandibular  foramen  in  the  mouth,  the  lingual  surface  of  the  ramus 
is  palpated  with  the  finger,  the  anterior  sharp  border  of  the  coronoid 
process  is  easily  felt  about  five-eighths  of  an  inch  posterior  of  the  third 
molar.  The  process  passes  downward  and  backward  of  the  third 
molar,  and  enters  into  the  external  oblique  line.  Mesially  from  this 
ridge  is  to  be  found  a  small  triangular  concave  plateau,  which  is 
facing  downward  and  outward,  being  bound  mesially  by  a  distinct 
bony  ridge  and  covered  with  mucous  membrane.  As  there  is  no 
anatomical  name  attached  to  this  space,  Braun  has  called  it  the  re- 
tro molar  triangle  (trigonum  retromolare).  In  the  closed  mouth  it  is 
located  at  the  side  of  the  upper  third  molar,  and  in  the  open  mouth 
it  is  found  midway  between  the  upper  and  lower  teeth.     Immediately 


LOCAL   ANESTHESIA.  413 

back  of  the  mesial  border  of  this  triangle,  directly  beneath  the  mucous 
membrane,  lies  the  lingual  nerve,  and  about  three-eighths  of  an  inch 
farther  back  the  mandibular  nerve  is  to  be  found.  This  last  nerve 
lies  close  to  the  bone,  and  enters  into  the  mandibular  foramen,  which  is 
partly  covered  by  the  mandibular  spine. 

Before  starting  the  injection  the  patient  should  be  cautioned  to 
rest  his  head  quietly  on  the  headrest  of  the  chair,  as  any  sudden  move- 
ment or  interference  with  the  hand  of  the  operator  may  be  the  cause 
of  breaking  the  needle  in  the  tissue.  The  syringe,  provided  with  a 
one-inch  needle,  is  held  in  a  horizontal  position,  resting  on  the  occlud- 
ing surfaces  of  the  teeth  from  the  cuspid  backward  and  slightly  toward 
the  median  line.  The  needle  is  to  be  inserted  three-eighths  of  an  inch 
above  and  the  same  distance  back  of  the  occluding  surface  of  the  third 
lower  molar,  the  needle  opening  facing  the  bone.  This  position  will 
insure  the  correct  direction  of  the  needle  point  so  as  to  reach  the  tissues 
immediately  surrounding  the  nerves,  and  not  lose  the  injection  in  the 
adjacent  thick  muscle  tissue.  The  needle  must  always  be  in  close  touch 
with  the  bone,  and  is  now  slowly  pushed  forward,  depositing  a  few  drops 
of  fluid  on  its  way  until  the  ridge  is  reached.  About  five  drops  of  fluid 
are  injected  in  this  immediate  neighborhood  for  the  purpose  of  anes- 
thetizing the  lingual  nerve.  The  needle  is  pushed  very  slowly  forward, 
always  keeping  in  close  touch  with  the  bone  and  depositing  fluid  on  its 
way,  until  it  is  pushed  in  about  five-eighths  of  an  inch.  It  is  impor- 
tant carefully  to  feel  the  way  along  the  bony  wall  of  the  ramus  as  the 
needle  may  have  to  pass  over  the  roughened  and  bony  elevations, 
which  afford  attachment  to  the  internal  pterygoid  muscle.  During 
the  injection  the  syringe  should  remain  in  the  same  horizontal  posi- 
tion as  heretofore  outlined.  Soon  after  the  injection,  paresthesia  of 
one-half  of  the  tongue  on  the  side  of  the  injection  occurs,  which  is  soon 
followed  by  anesthesia  of  the  mandibular  nerve.  Paresthesia  of  the 
mucous  membrane  and  half  of  the  lower  lip  is  also  estabhshed.  The 
pulps  of  the  lower  teeth,  including  the  cuspid  and  lateral  incisor  and 
the  gum  tissue  on  both  sides  of  the  jaw,  are  anesthetized,  including  a 
part  of  the  anterior  floor  of  the  mouth.  The  complete  anesthesia  of 
the  two  nerves  also  anesthetizes  the  whole  alveolar  process  in  this 
region.  About  five  minutes  are  required  for  the  complete  anesthe- 
tization of  the  lingual  nerve,  and  at  least  fifteen  minutes  for  the  man- 
dibular nerve.  Braun  claims  that  the  injection  is  absolutely  free  from 
danger,  while  Romer  states  that  danger  may  arise  if  the  whole  quantity 
of  the  solution  should  accidentally  be  injected  into  a  vein. 

The  mental  foramen  lies  midway  between  the  superior  and  in- 


414  LOCAL    ANESTHESIA. 

ferior  border  of  the  body  of  the  mandible  on  its  external  surface, 
usually  below  the  second  bicuspid  teeth.  Its  opening  always  faces 
posteriorly.  An  injection  near  this  point  increases  the  anesthesia  in 
the  bicuspid  region.  The  incisive  fossa  is  a  shallow  depression  on 
the  external  surface  of  the  mandible  between  the  cuspid  teeth.  It 
may  be  located  by  the  palpating  finger  immediately  above  the  chin. 
A  number  of  small  foramina  are  found  in  this  region  for  the  passage 
of  nerves  and  nutrient  vessels.  The  lower  incisors  may  be  anes- 
thetized by  making  injections  anteriorly  into  the  incisive  fossa  and 
one  posteriorly  in  the  region  corresponding  to  the  fossa.  Usually, 
peridental  anesthesia  is  to  be  preferred  for  these  teeth. 

Conductive  anesthesia  is  serviceable  if  a  number  of  teeth  have 
to  be  removed  at  one  visit.  It  should  be  borne  in  mind,  however, 
that  in  average  only  one-half  of  either  jaw  should  be  anesthetized 
at  one  sitting  so  as  to  keep  the  quantity  of  the  injected  anesthetic 
solution  within  the  limits  of  ordinary  dosage. 

The  Injection  into  the  Pulp. — By  pressure  anesthesia,  pressure 
cataphoresis,  or  contact  anesthesia,  as  the  process  is  variously  termed, 
we  understand  the  introduction  of  a  local  anesthetizing  agent  in  solu- 
tion by  mechanical  means  through  the  dentin  into  the  pulp  for  the 
purpose  of  rendering  this  latter  organ  insensible  to  pain.  Simple 
hand  pressure  with  a  suitable  instrument,  the  hypodermic  syringe 
or  the  so-called  high  pressure  syringe,  is  recommended  for  such  pur- 
poses. Regarding  the  principles  of  pressure  anesthesia,  it  should  be 
remembered  that  we  cannot  force  a  liquid  through  healthy  dentin  by 
a  mechanical  device  without  injury  to  the  tooth  itself.  If  a  cocain 
solution  is  held  in  close  contact  with  the  protoplasmic  fibers  of  the 
dentin,  the  absorption  of  cocain  takes  place  in  accordance  with  the 
law  of  osmosis.  The  imbibition  of  the  anesthetic  is  enhanced  by  em- 
ploying a  physiological  salt  solution  as  a  vehicle.  On  the  other  hand, 
living  protoplasm  reacts  unfavorably  against  the  ready  absorption  of 
substances  by  osmosis  for  two  reasons:  (i)  Its  albumin  molecule  is 
relatively  large  and  not  easily  diffusible,  and  (2)  as  an  integral  part  of 
its  life  it  possesses  "vital"  resistance  toward  foreign  bodies.  These 
latter  factors  are  sufficiently  demonstrated  by  the  fact  that  it  is  very 
difficult  to  strain  living  tissue.  Dehydration  of  the  protoplasm  in- 
creases the  endosmosis  of  the  anesthetic  solution  markedly. 

When  we  apply  the  same  "pressure"  anesthesia  upon  carious 
dentin,  the  above  statements  do  not  hold  good.  We  are  able  to  press 
fluids  quite  readily  through  carious  dentin.  We  must  bear  in  mind 
that  such  dentin  has  been  largely  deprived  of  its  inorganic  salts,  leaving 


LOCAL    ANESTHESIA.  415 

an  elastic  spongy  matrix  in  position.  By  drying  out  this  dentin  and 
then  confining  the  anesthetic  solution  under  a  suitable  water-tight 
cover,  the  pressure  applied  by  the  finger  is  quite  sufficient  to  obtain  the 
results.  Colored  fluids  may  be  readily  pressed  through  such  dentin  and 
even  stain  the  pulp. 

In  teeth  not  fully  calcified  and  in  so-called  soft  teeth,  pressure 
anesthesia  is  more  readily  obtained  while,  according  to  Zederbaum, 
the  process  fails  in  "teeth  of  old  persons,  teeth  of  inveterate  tobacco 
chewers,  worn,  abraded  and  eroded  teeth,  teeth  with  extensive  second- 
ary calcific  deposits,  teeth  whose  pulp  canals  are  obstructed  by  pulp 
nodules,  teeth  with  metallic  oxides  in  tubules,  teeth  with  leaky  old 
fillings,  badly  calcified  teeth — ^mainly  all  from  one  and  the  same  cause, 
namely,  clogged  tubuh.  In  most  cases  no  amount  of  persistent  pres- 
sure will  prove  successful." 

From  the  foregoing  it  will  be  observed  that  the  so-called  high 
pressure  syringes  possess  little  merit  relative  to  pressure  anesthesia. 
The  pressure  which  can  be  produced  by  a  good  working  all-metal 
syringe,  holding  it  between  the  index  and  middle  fingers  and  forcing 
the  piston  with  the  thumb,  amounts  to  250  to  300  pounds  in  the  average 
man.  The  pressure  required  in  pressure  anesthesia  to  produce  a 
perfect  contact  is  usually  much  less  than  the  above  force. 

Methods  of  Anesthetizing  the  Pulp. — i.  The  pulp  is  wholly  or  par- 
tially exposed.  Isolate  the  tooth  with  the  rubber  dam  and  clean  it 
with  water  and  alcohol.  Excavate  the  cavity  as  much  as  possible 
and  if  the  pulp  is  not  exposed,  dehydrate  with  alcohol  and  hot  air. 
Saturate  a  pledget  of  cotton  or  a  piece  of  spunk  with  a  concentrated 
cocain  or  novocain  solution,  place  it  into  the  prepared  cavity  and 
cover  it  with  a  piece  of  vulcanizable  rubber  and  with  a  suitable  bur- 
nisher apply  slowly,  increasing  continuous  pressure  from  one  to  three 
minutes.  The  pulp  may  now  be  exposed  and  tested.  If  it  is  still 
sensitive,  repeat  the  process.  Loeffler  states  that  "  this  pressure  may 
be  applied  by  taking  a  short  piece  of  orange  wood,  fit  it  into  the  cavity 
as  prepared,  and  direct  the  patient  to  bite  down  upon  this  with  in- 
creasing force.  In  this  way  we  can  obtain  a  well-directed  regulated 
force  or  pressure,  and  with  less  discomfort  to  the  patient  and  operator." 
Miller  described  this  process  as  follows:  "After  excavating  the 
cavity  as  far  as  convenient  and  smoothing  the  borders  of  it,  take  an 
impression  in  modeling  compound,  endeavoring  to  get  the  margins 
of  the  cavity  fairly  well  brought  out;  put  a  few  threads  of  cotton  into 
the  cavity  and  saturate  them  thoroughly  with  a  5  to  10  per  cent  solu- 
tion of  cocain,  cover  this  with  a  small  bit  of  rubber  dam,  and  then 


4l6  LOCAL   ANESTHESIA. 

press  the  compound  impression  down  upon  it.  We  obtain  thereby  a 
perfect  closure  of  the  margin,  so  that  the  liquid  cannot  escape  and  one 
can  then  exert  pressure  with  the  thumb  sufl&cient  to  press  the  solution 
into  the  dentin. 

2.  The  pulp  is  covered  with  a  thick  layer  of  healthy  dentin.  With 
a  very  small  spade  drill  bore  through  the  enamel  or  direct  into  the  dentin 
at  a  most  convenient  place,  guiding  the  drill  in  the  direction  of  the  pulp 
chamber.  Blow  out  the  chips,  dehydrate  with  alcohol  and  hot  air, 
and  apply  the  syringe  provided  with  a  special  needle,  making  as  nearly 
as  possible  a  water-tight  point.  Apply  slow,  continuous  pressure  for 
two  or  three  minutes.  With  a  round  burr  the  pulp  should  now  be 
exposed,  and  if  still  found  sensitive,  the  process  is  to  be  repeated. 

Recently  a  method  has  come  into  vogue  which  allows  successful 
anesthetization  of  the  pulp  by  injecting  the  anesthetic  solution  around 
the  apex  of  the  tooth.  The  spongy  alveolar  process,  which  contains 
lymph  channels,  allows  the  ready  penetration  of  the  fluid.  The 
injection  should  be  made  close  to  the  bone,  pushing  the  needle  slowly 
toward  the  apex,  while  the  fluid  is  deposited  drop  by  drop.  No 
wheal  should  be  raised  by  the  injection,  otherwise  the  benefits  of  the 
pressure  from  the  dense  gum  tissue  is  lost. 

According  to  Hertwig,  the  protoplasm  of  the  cell  primarily  transfers 
irritation;  and,  secondly,  transmits  absorbed  materials.  Therefore, 
the  anesthetic  solution  has  to  pass  through  the  entire  dentinal  fiber 
because  the  nerve  tissue  of  the  pulp  proper  is  reached.  Consequently 
a  certain  period  of  time  is  required  before  the  physiological  effect  of 
the  anesthetic  is  manifested.  This  period  of  latency  is  dependent 
upon  the  thickness  of  the  intermediate  layer  of  dentin  or  bone.  The 
successful  anesthetization  of  the  pulp  depends  largely  upon  this  most 
important  factor  of  allowing  sufl&cient  time  for  the  proper  migration 
and  action  of  the  drug. 

The  anesthetizing  of  the  peridental  membrane  for  the  treatment 
of  pyorrhea  alveolaris  is  a  comparatively  simple  matter  if  carried  out 
according  to  the  methods  as  outlined  under  the  heading  of  peridental 
anesthesia.  Sometimes  a  topical  application  of  a  fairly  concentrated 
novocain-adrenalin  solution  (about  lo  per  cent)  and  applied  to  the 
pockets  by  means  of  cotton  ropes  accomplishes  the  desired  purpose. 
The  surgical  treatment  of  pyorrhea  is  materially  simplified  if  the  tissues 
under  consideration  are  relieved  of  sensation. 

Local  anesthesia  for  operations  about  the  mouth,  exclusive  of  the 
extraction  of  teeth. 

In  operating  about  the  mouth  for  an  abscess,  a  cystic  or  a  solid 


LOCAL   ANESTHESIA.  417 

tumor  of  the  approximate  size  of  a  large  walnut,  a  malposed  tooth, 
or  for  any  other  purpose,  the  rhomboid  infiltration  according  to 
Hackeilbruch  affords  the  simplest  means  of  producing  a  most  satis- 
factory anesthesia.  After  previously  cleansing  the  field  of  operation 
with  an  antiseptic  solution,  a  very  small  drop  of  phenol  is  placed  at 
A  and  B  to  superficially  obtund  the  point  of  puncture.  The  needle 
is  quickly  thrust  through  the  mucosa  at  A,  and  at  once  slow  pres- 
sure is  exerted  on  the  piston,  moving  the  needle  steadily  along  the 
external  line  of  the  tumor.  The  needle  is  now  partially  withdrawn, 
without,  however,  leaving  the  original  puncture,  and  a  second  injec- 
tion or  as  many  as  may  be  needed  are  made  in  opposite  directions. 
This  maneuver  is  now  repeated  at  B  and  thus  a  circumscribed  infil- 
tration of  the  whole  tumor  is  obtained.  If  the  tumor,  etc.,  is  very 
large,  additional  punctures  and  injections  may  be  made  as  outlined 
in  the  schematic  drawing.  After  ten  to  fifteen  minutes'  waiting  the 
extirpation  of  the  tumor  may  be  begun.  For  injecting  the  soft  tis- 
sues other  than  the  gum  a  i  per  cent  novocain — adrenalin  solution — 
one  tablet  dissolved  in  2  c.c.  of  water — ^is  quite  sufficient. 

The  anesthetization  of  the  soft  and  hard  palate  is  comparatively 
easily  accomplished.  The  injection  on  the  hard  palate  is  started  at 
the  gingival  edge  of  the  alveolar  periosteum  on  both  sides  of  the  jaw 
toward  the  median  line.  As  the  gum  tissue  is  extremely  dense,  great 
force  is  required  for  a  complete  infiltration  in  this  region,  and  only 
small  quantities  of  the  solution  are  required.  The  soft  palate  is  easily 
infiltrated  by  inserting  the  curved  needle  posteriorly  to  the  third 
molar. 

Small  tumors  and  cysts  on  the  tongue  or  the  floor  of  the  mouth 
are  best  anesthetized  by  the  rhomboid  infiltration  of  Hackenbruch. 
For  the  complete  extirpation  of  a  ranula,  the  injection  is  made  into 
the  cyst  wall  near  the  periphery,  after  which  the  cyst  is  slit  open  and 
a  small  quantity  of  the  anesthetic  solution  is  injected  into  the  inner 
surface  of  the  cyst.  Large  cysts,  tumors  and  major  operations  on 
the  tongue  require  the  anesthetization  of  both  lingual  nerves.  In 
injecting  and  operating  on  the  floor  of  the  mouth,  the  index  finger  of 
the  left  hand  should  be  placed  on  its  external  surface  as  a  guide  to  the 
needle  or  the  knife. 

Local  anesthesia  is  indicated  in  all  minor  and  in  relatively  many 
major  operations  on  the  mucous  surfaces,  the  skin,  and  the  teeth. 
Local  anesthesia  is  not  a  substitute  for  general  anesthesia;  its  use- 
lessness  is  materially  increased  by  familiarizing  one's  self  with  the 
modern  methods  of  its  production  and  with  a  perfect  mastering  of 


4l8  LOCAL    ANESTHESIA. 

the  technique.  The  danger  of  poisoning  has  been  practically  elimi- 
nated by  using  isotonic  solutions  containing  a  relative  small  percent- 
age of  the  anesthetic  in  combination  with  the  alkaloid  of  the  supra- 
renal capsule.  Even  if  the  danger  of  general  necrosis  is  small  under 
the  very  best  conditions,  the  danger  from  local  anesthesia  is  always 
less.  The  greater  majority  of  all  dental  operations  can  be  safely 
carried  out  under  local  anesthesia,  provided  the  operator  has  acquired 
a  complete  working  knowledge  of  the  various  components  which,  as  a 
whole,  constitute  this  important  branch  of  dental  therapeutics. 


CHAPTER   XXVI. 
THE  EXTRACTION  OF  TEETH. 

BY    FERDINAND    J.    S.    GORGAS,    A.M.,  M.D,,   D.  D.  S. 

The  extraction  of  teeth,  although  usually  regarded  as  a  minor 
surgical  operation,  is,  nevertheless,  an  operation  that  frequently  pre- 
sents great  difficulties,  and  is,  perhaps,  more  often  performed  than 
any  other  in  surgery.  To  successfully  extract  teeth  requires  an  accurate 
knowledge  of  the  histology,  anatomy,  and  physiology  of  these  organs, 
and  the  structures  in  direct  relationship  with  them.  The  anatomy 
referred  to,  denominated  "  dental  anatomy,"  includes  that  part  of  the 
science  of  organic  structure  which  relates  to  the  bones  of  the  head, 
especially  the  jaws;  the  origin  and  distribution  of  the  vessels  and  nerves 
supplying  the  dental  tissues  with  blood  and  sensation;  also  a  knowl- 
edge of  the  muscles  concerned  in  moving  the  lower  jaw,  as  well  as 
those  which  are  instrumental  in  producing  the  varied  facial  expressions. 

As  the  teeth  are  of  dermal  origin — morphological  appendages  of 
the  skin,  and  compared  with  such  tissues  as  hair  and  nails — the  origin 
and  development  of  their  hard  structures,  viz.,  enamel,  dentin,  and 
ceiAentum,  should  be  well  understood. 

The  teeth,  as  before  stated,  being  dermal  appendages,  are  not  a  part 
of  the  osseous  system,  and  the  science  of  embryonic  evolution  teaches 
that  they  are  inserted  in  sockets,  as  is  common  with  all  large  teeth, 
and  also  that  they  have  a  strong  attachment.  In  the  human  subject  all 
the  teeth  are  imbedded  in  well-developed  alveolar  cavities  of  the  supe- 
rior and  inferior  maxillary  bones,  their  function  being  to  seize,  bite,  and 
masticate  the  food. 

The  enamel  is  derived  from  the  ectoderm,  differing  in  this  respect 
from  bone,  which  is  a  product  of  the  mesoderm.  The  enamel  cover- 
ing the  exposed  portion,  or  crown,  of  the  tooth,  being  its  protective 
covering,  is  the  hardest  structure  in  the  body,  and  is  not,  like  bone, 
regenerated.  Its  structural  elements  are  enamel  rods  or  prisms,  and 
interprismatic  or  cement  substance,  which  holds  the  rods  or  prisms 
together.  When  fractured,  the  tissue  separates  along  the  cemental 
line — this  is  known  as  the  cleavage  of  the  enamel. 

The  dentin  is  derived  from  the  mesoderm,  and  constitutes  the  body 
of  the  tooth,  determines  its  form,  and  is  similar,  in  respect  to  its  origin, 

419 


420  THE    EXTRACTION    OF    TEETH. 

to  bone.  The  structural  elements  of  the  dentin  are  minute  canals — 
tubules,  and  intertubular  sulpstance,  the  canals  radiating  from  a  central 
cavity  which  contains  the  pulp  of  the  tooth. 

The  cementum,  which  covers  the  root  of  the  tooth  and  incloses  the 
dentin,  at  the  gingival  border  or  neck  of  the  tooth,  slightly  overlapping 
the  enamel,  is  a  variety  of  bone  tissue,  destitute,  however,  of  the  Haver- 
sian canals  common  to  bone,  but  contains  lacunae  and  canaliculi  like 
bone.  The  cementum  is  composed  of  parallel  lamellae  of  bone  tissue, 
small  vessels  penetrating  these  thin  plates,  while  other  vessels,  derived 
from  the  pulp,  pass  through  the  cementum  in  the  opposite  direction. 
Fibers  from  the  investing  membrane  of  the  root  of  the  tooth — peri- 
cemental membrane,  and  which  resemble  the  fibers  of  Sharpey  in  bone 
— are  firmly  attached  to  the  cementum,  and  furnish  a  medium  of  con- 
nection by  which  the  tooth  is  securely  held  in  its  alveolar  cavity;  they 
also  account  for  the  resistance  offered  by  the  tooth  to  its  forcible  re- 
moval by  the  forceps. 

The  pericemental  membrane  lines  the  alveolar  cavity  and  surrounds 
the  root  of  the  tooth.  Its  cellular  elements  are  fibroblasts,  osteoblasts, 
osteoclasts,  and  epithelial  cells,  the  latter  being  located  between  the 
fibers  of  the  membrane. 

The  fibers  of  the  pericemental  membrane,  formed  and  renewed  by 
the  fibroblasts,  extend  into  the  cementum  and  have  a  transverse  direc- 
tion, being  attached  at  one  extremity  to  the  cementum  of  the  root  of 
the  tooth,  and  at  the  other  to  the  bony  wall  of  the  alveolar  cavity. 
Resembling  Sharpey's  fibers  of  bone,  these  fibers  of  the  pericemental 
membrane  are  white  and  inelastic,  their  function  being  to  increase  and 
renew  the  fibrous  tissue  of  the  membiane  by  which  the  toQth  is  sup- 
ported in  place. 

This  fibrous  tissue  consists  of  two  varieties,  one  of  which  is  coarse 
and  radiating,  and  forms  the  bulk  of  the  tissue,  and  by  its  strength 
firmly  secures  the  tooth;  the  other  variety  is  fine  and  interlaces  with 
the  coarse  variety,  being  connected  with  the  blood  vessels  permeating 
the  tissue.  From  the  gingival  portion  of  the  cementum,  the  fibers  of 
the  pericemental  membrane  pass  horizontally,  some  of  them  connect- 
ing with  the  membrane  of  adjoining  teeth,  and  others  passing  into  the 
connective  tissue  of  the  adjacent  mucous  membrane,  thus  giving  hard- 
ness to  the  gums.  The  pericemental  membrane  is  richly  supplied 
with  blood,  some  of  the  vessels  entering  the  membrane  near  the  apex 
of  the  root,  others  from  the  Haversian  canals,  while  a  third  supply  is 
derived  from  the  mucous  membrane  of  the  gum  near  the  gingival 
border. 


THE  EXTRACTION  OF  TEETH. 


421 


The  teeth,  being  of  dermal  origin,  are  attached  by  insertion  into 
well-developed  cavities  in  the  alveolar  processes  of  the  jaws,  which  are 
known  as  alveoli,  and  which  are  formed  by  the  outer  and  inner  plates 
of  the  alveolar  process.  The  shape,  size,  and  length  of  the 
roots  of  the  teeth  determine  the  shape,  size  and  depth  of  the 
alveoli.  (Fig.  283.)  Each  alveolus  consists  of  compact  bone  tissue 
surrounded  by  cancellated  or  spongy  tissue,  which  acts  as  a  cushion 
against  the  shocks  of  mastication.  The  outer  and  inner  plates  of  the 
alveolar  process  are  connected  by  numerous  septa  which  outline  the 
shapes  of  the  orifice  of  the  cavities  of  the  teeth.  Dr.  I.  Norman 
Broomell,  in  his  treatise  on  the  "Anatomy  and  Histology  of  the 
Teeth,"  describes  the  alveoli  as  follows  (Figs.  284,  285  and  286) : 
"The  first  socket,  or  that  next  to  the  mesial  surface  of  the  bone,  gives 
support  to  the  central  incisor  tooth.     It  forms  almost  a  perfect  cone, 


Fig.  283. 

and  has  an  average  depth  of  almost  half  an  inch.  Its  lower  border  is 
circular,  and  the  anterior  or  labial  portion  describes  a  larger  circle  than 
the  posterior  or  palatal  half.  The  mesial  and  distal  walls  are  somewhat 
flattened.  The  second  cavity  proceeding  backward  from  the  mesial 
line,  supports  the  lateral  incisor  tooth.  It  is  also  conic,  but  much 
smaller  than  the  preceding.  It  is  seldom  over  |  to  j\  of  an  inch  in 
depth.  It  is  much  flattened  on  its  mesial  and  distal  walls,  giving  the 
appearance  of  an  oblong,  rather  than  a  round  cavity.  This  socket, 
as  well  as  that  for  the  central  incisor,  occupies  an  almost  vertical  position 
in  the  process.  Very  frequently  the  socket  for  the  lateral  incisor 
presents  a  slight  distal  curve  at  its  upper  extremity.  The  third  socket, 
or  that  giving  support  to  the  cuspid  tooth,  is  much  larger  and  deeper 
than  those  previously  described.  It  extends  upward,  inward,  and 
backward,  to  the  average  depth  of  f  to  f  of  an  inch.  In  transverse 
section,  its  labial  wall  presents  a  much  larger  circle  than  its  palatal 


422 


THE  EXTRACTION  OF  TEETH. 


margin.  The  labial  and  distal  walls  are  much  flattened  and  some- 
what convex.  The  general  direction  of  this  socket  is  to  the  distal. 
The  socket  which  supports  the  first  bicuspid  is  usually  divided  from 
mesial  to  distal  by  a  thin  septum  of  bone,  thus  forming  an  outer  or 


Fig.  284. 


buccal  socket,  and  an  inner  or  palatal  socket.  This  division  seldom 
exists  to  the  full  depth  of  the  cavity,  but  usually  begins  about  midway 
of  its  length.  The  lower  margin  of  this  socket  is  oblong  or  egg-shaped, 
its  outer  or  buccal  portion  forming  a  larger  curve  than  its  palatal. 


Fig.  285. 

The  lateral  walls  are  slightly  concave  or  flattened,  until  the  point  of 
separation  is  reached,  when  they  become  more  circular,  the  alveoli 
above  this  point  becoming  cone-shaped. 

"It  is  not  uncommon  for  this  socket  to  be  a  single  cavity,  and  when 


THE    EXTRACTION    OF    TEETH.  423 

thus  formed  it  resembles  a  flattened  cone,  with  the  buccal  and  palatal 
margins  rounded. 

"The  next  socket  gives  support  to  the  second  bicuspid  tooth,  in  most 
instances  being  a  single  cavity,  but  in  rare  instances  it  is  divided  near  its 
upper  extremity.  In  general  outline  it  resembles  the  socket  for  the 
first  bicuspid.  The  socket  for  the  first  molar  is  much  larger  than  any 
of  those  previously  described;  its  inferior  margin  presents  a  circular 
outline  on  its  buccal  and  palatal  portions, 
the  former  curve  being  larger  than  the 
latter.  The  mesial  and  distal  walls  are 
flattened  and  slightly  concave.  The 
upper  three-fourths  of  this  socket  is 
divided  into  three  separate  compart- 
ments, being  so  arranged  that  two  are 
on  the  buccal  and  one  upon  the  palatal 
side.  The  septa  separating  the  two 
buccal  cavities  from  the  palatal  cavity 
are  heavy  and  strong,  while  that  placed 
between  the  two  buccal  sockets  is  thin 
and  frail.  The  two  buccal  cavities  are 
usually  flattened  upon  their  mesial  and 
distal  sides.  The  palatal  socket  is  larger 
and  somewhat  deeper  than  the  buccal, 
the  average  depth  of  all  being  about  ^  an 

^^^^-  Fig.  286. 

"The  socket  for  the  second  molar  is 

similar  in  most  respects  to  that  for  the  first  molar,  except  that  it  is 
somewhat  smaller.  The  same  description  might  answer  for  the  third 
molar  socket,  which  in  general  is  similar  to  the  alveoli  for  the  other 
molars.  It  is  smaller  than  the  second  molar  socket,  and  may  be  a 
single  cavity,  or  it  may  be  divided  into  three  or  more  compartments." 
(Fig.  284.) 

The  average  length  of  an  upper  central  incisor  root  in  the  fraction  of 
an  inch  is  .49;  of  an  upper  lateral  incisor  is  .5 1 ;  of  £> n  upper  cuspid  .68 ;  of 
an  upper  first  bicuspid  .48;  of  an  upper  second  bicuspid  .55;  of  an 
upper  first  molar  .51;  of  an  upper  second  molar  .51;  of  an  upper  third 
molar  .44;  of  a  lower  central  incisor  .47;  of  a  lower  lateral  incisor  .50; 
of  a  lower  cuspid  .60;  of  a  lower  first  bicuspid  .54;  of  a  lower  second 
bicuspid  .56;  of  a  lower  first  molar  .52;  of  a  lower  second  molar  .50; 
of  a  lower  third  molar  .36.* 

*  These  measurements  are  taken  from  Black's  Dental  Anatomy.    . 


424  THE  EXTRACTION  OF  TEETH. 

The  upper  central  incisor  has  a  single  root  which  is  of  conical  form, 
its  labial  side  more  flattened  than  its  lingual.  The  mesial  and  distal 
surfaces  of  this  root  are  also  somewhat  flattened,  and  taper  gradually 
from  the  base  to  the  apex.  The  upper  lateral  incisor  has  also  a  single 
root,  which  is  conical  in  form,  and  much  more  flattened  from  the  mesial 
to  the  distal  surfaces  than  the  root  of  the  central  incisor.  At  the  junc- 
tion of  the  root  with  the  crown  this  root  is  circular  in  form,  the  labial 
portion  forming  the  segment  of  a  larger  circle  than  the  lingual  portion; 
it  is  generally  a  straight  root.  The  upper  cuspid  has  also  a  single 
root,  which  is  the  largest  and  longest  of  any  of  the  teeth;  it  is  rounded  on 
the  labial  and  lingual  surfaces,  the  labial  forming  the  segment  of  a 
larger  circle  than  the  lingual.  This  root  gradually  diminishes  in  size 
from  the  neck  of  the  tooth  to  its  apex,  and  forms  a  perfect  cone.  The 
upper  first  bicuspid  has  usually  two  roots  (although  sometimes  it  has 
but  one),  w^hich  are  quite  similar  in  form.  The  buccal  root,  however, 
is  usually  a  little  longer  than  the  lingual  root,  and  both  roots  taper  to 
slender  apexes  with  an  inclination  to  curve  at  their  extremities.  The 
point  of  bifurcation  of  these  roots  is  usually  some  distance  above  the 
neck  of  the  tooth. 

When  this  tooth  has  a  single  root,  it  is  much  flattened  from  the 
mesial  to  the  distal  surface,  indicating  a  tendency  toward  the  formation 
of  two  roots.  The  second  upper  bicuspid  has  usually  a  single  root 
which  is  round  on  the  buccal  and  lingual  surfaces,  and  flattened  on 
the  mesial  and  distal  surfaces.  The  upper  first  molar  has  three  roots, 
two  buccal  and  one  lingual,  the  disto-buccal  being  the  smallest,  and 
more  rounded  than  the  mesio-buccal  root.  The  lingual  root  is  the 
largest  and  longest  of  the  three  roots,  forming  a  long  curve  which  ends 
in  a  sharp-pointed  apex.  The  upper  second  molar  has  also  three 
roots,  two  buccal  and  one  lingual,  which  are  much  smaller  than  those 
of  the  first  molar,  and  are  more  inclined  to  converge  than  to  diverge. 
In  general  outlines  they  resemble  those  of  the  first  molar.  The  root 
of  the  upper  third  molar,  like  the  crown,  is  subject  to  a  greater  variety 
of  form  and  number  of  roots  than  any  other  tooth  in  the  mouth. 
Normally  it  has  the  same  number  of  roots  as  the  two  preceding  molars, 
but  sometimes  as  many  as  four  or  five  are  developed.  Frequently, 
the  three  roots  are  so  fitsed  together  as  to  present  a  single  root  with  a 
line  of  demarcation  between  them,  thus  indicating  by  such  an  outline 
the  character  of  the  tooth. 

The  lower  central  incisor  has  a  single  root  which  is  usually  smaller 
than  that  of  any  other  tooth,  and  is  flattened  from  the  mesial  to  the 
distal  surface,  while  its  labial  and  lingual  surfaces  are  rounded.     The 


THE  EXTRACTION  OF  TEETH.  425 

broad  mesial  and  distal  surfaces  of  this  root,  which  is  straight,  taper 
gradually  from  the  neck  to  the  apex. 

The  root  of  a  lower  lateral  incisor  is  shghtly  longer  and  larger,  but 
in  other  respects  is  similar  to  that  of  the  lower  central  incisor.  The 
root  of  the  lower  cuspid  is  shorter  and  more  flattened  on  its  mesial 
and  distal  surfaces  than  that  of  the  upper  cuspid.  Its  labial  and 
lingual  surfaces  are  convex,  and,  like  that  of  the  upper  cuspid,  the 
labial  forms  the  segment  of  a  larger  circle  than  the  Ungual.  The  root 
of  the  lower  first  bicuspid  is  usually  single  and  straight,  tapering  gradu- 
ally from  the  neck  to  the  apex.  Its  buccal  and  lingual  surfaces  are 
convex,  while  the  mesial  and  distal  surfaces  may  sometimes  be  slightly 
convex,  or  flattened,  and  present  a  slight  longitudinal  concavity.  The 
root  of  the  lower  second  bicuspid  is  also  single,  and  is  larger  and  longer 
than  the  root  of  the  lower  first  bicuspid,  and  its  mesial  and  distal  sur- 
faces are  also  similar.  In  some  cases  it  tapers  gradually  from  the 
neck  to  the  apex,  while  in  others  its  apex  may  be  blunt  and  rounded. 

The  roots  of  the  lower  first  molar,  two  in  number,  situated  imme- 
diately beneath  the  mesial  and  distal  halves  of  the  crown,  are  greatly 
flattened  from  the  mesial  to  the  distal  surfaces,  and  each  is  broad  at 
the  neck  from  the  buccal  to  the  lingual  surface.  The  mesial  root  is 
usually  larger  and  longer  than  the  distal  root,  the  latter  having  a  longi- 
tudinal depression  which  renders  it  weaker  than  the  mesial  root. 
The  distal  root  is  generally  straight,  and  gradually  tapers  from  the 
neck  to  the  apex,  ending  in  a  pointed  extremity.  The  lower  second 
molar  has  also  two  roots,  a  mesial  and  a  distal,  which  are  generally 
closer  together  than  those  of  the  lower  first  molar,  and  are  less  flattened 
upon  their  mesial  and  distal  surfaces,  and  are  more  rounded,  and  taper 
more  gradually  from  their  necks  to  their  apexes,  which  terminate 
in  rounded  ends.  The  roots  of  the  lower  third  molars  are  norrrially 
two  in  number,  like  those  of  the  lower  first  and  second  molars,  but 
frequently  a  single  conical  root  is  presented;  in  other  cases  three  roots 
may  be  developed,  which  are  usually  crooked  and  irregular,  with  a 
tendency  to  diverge  from  the  crown. 

Under  normal  conditions,  and  if  performed  on  scientific  principles, 
tooth-extraction  is  not  a  difficult  operation;  although  cases  are  some- 
times met  with,  where,  owing  to  abnormal  conditions,  the  operation 
requires  considerable  judgment  and  skill,  severely  trying  the  patience 
of  the  operator  and  the  endurance  of  the  patient.  It  is  therefore 
difficult  to  formulate  special  rules  which  may  be  literally  followed. 
The  axiom,  which  is  an  established  rule  in  all  surgical  procedures, 
that  "every  operation  is  performed  quick  enough  that  is  performed 


426  THE    EXTRACTION    OF    TEETH. 

well,"  is  particularly  applicable  to  tooth-extraction.  A  kind  manner 
and  a  tender  regard  for  the  physical  and  mental  suffering  of  the  patients, 
on  the  part  of  the  operator,  will,  in  the  majority  of  cases,  so  impress 
them,  that  they  will  quietly  submit  to  his  judgment  and  skill.  It  is 
well  never  to  promise  more  than  it  is  probable  can  be  performed;  and 
in  the  case  of  children,  to  adhere  to  the  truth,  for  deception  may  render 
a  first  operation  easy  of  accomplishment,  but  will  react  in  the  case  of  a 
second  one,  and  leave  such  unhappy  impressions  upon  the  mind  that 
years  cannot  entirely  efface. 

Excessive  solicitude  should  also  be  avoided  upon  the  part  of  the 
operator,  and  in  all  cases  patience  and  gentleness  should  be  exercised. 
The  unnecessary  display  of  instruments,  together  with  the  preparation 
of  them  in  the  presence  of  the  patient,  should  also  be  avoided. 

While  it  is  true  that  the  most  expressive  lamentations  by  the  patient 
do  not  invariably  indicate  acute  suffering,  yet  there  are  other  cases 
where  no  outward  manifestations  of  pain  may  be  exhibited,  and  at  the 
same  time  the  effect  on  the  nervous  system  be  such  as  to  severely  tax 
the  vital  energy.  Hence  it  is  better  not  to  exact  too  much  of  a  nervous 
patient,  who  may  heroically  nerve  herself  to  quietly  endure  intense 
suffering,  and  show  no  visible  signs  of  agony. 

The  question  as  to  "whether  or  no  a  tooth  is  to  be  extracted"  may 
be  answered  as  follows:  "  When  a  tooth  or  a  part  thereof  can  be  made 
of  no  further  use  to  the  patient,  or  when  its  retention  cannot  be  ac- 
complished with  comfort  to  its  possessor,  or  when  its  presence  prevents 
the  correction  of  more  important  teeth,  it  should  be  extracted."  Such 
an  answer  may  embrace  all  indications  for  this  operation.  On  the 
other  hand  certain  conditions  which  have  been  termed  "contra- 
indications" against  tooth-extraction  have  been  advanced  with  more 
or  less  reason.  The  following  are  the  more  important:  The  avoidance 
of  such  an  operation  during  the  periods  of  menstruation,  gestation,  and 
lactation,  as  it  may  seriously  interfere  with  these  functions.  The 
more  prominent  of  these  contra-indications,  however,  is  the  condition 
of  pregnancy,  as  the  shock  of  such  an  operation  as  tooth-extraction 
may,  it  is  asserted,  cause  miscarriage  at  certain  periods  of  its  existence. 

The  term  "abortion"  signifies  the  expulsion  of  the  product  of 
conception  from  the  womb  before  the  end  of  the  yth  month,  and  is 
the  great  accident  of  pregnancy. 

It  is  most  liable  to  occur  during  the  3rd,  4th,  and  5th  months 
of  gestation,  for  the  reason  that  at  these  periods,  there  is  no  adhesion 
between  the  ovum  and  uterus.  As  soon  as  the  chorion  and  the  decidua 
are  developed,  separation  of  these  organs  becomes  more  difficult,  and 


THE    EXTRACTION    OF    TEETH.  427 

miscarriage  is  not  so  prone  to  occur;  hence,  the  danger  of  such  an  ac- 
cident diminishes  as  gestation  advances. 

When  it  is  absolutely  necessary  to  extract  a  tooth  at  a  certain  period 
in  this  condition,  and  palliative  measures  have  failed  to  give  relief, 
and  extraction  will  prove  to  be  a  lighter  tax  upon  the  patient's  vital 
powers  than  a  severe  and  prolonged  attack  of  toothache,  and  especially 
if  a  proneness  to  abortion  exists,  the  family  physician  should  be  con- 
sulted, and  the  dental  practitioner  be  governed  by  his  opinion.  The 
pathological  conditions  of  the  uterus  which  predispose  to  abortion, 
comprise  all  that  interfere  with  the  development  of  the  ovum,  such  as 
displacement,  inflammatory  affections  of  the  lining  membrane,  uterine 
tumors,  disease  of  the  ovaries,  rectum  and  bladder;  the  most  common 
causes  of  abortion  are  to  be  found  in  the  ovum.  An  affection  which 
has  been  regarded  as  another  contra-indication  is  hemophilia  (hemor- 
rhagic diathesis).  This  condition  is  characterized  by  severe  bleeding 
from  trivial  injuries,  and  is  generally  hereditary,  and  transmitted 
through  the  females  to  their  male  descendants.  It  is  due  to  a  decrease 
of  coagulability  in  the  blood;  also  to  changes  in  the  vessels, such  as  may 
be  caused  by  disease,  the  vessels  becoming  so  weak  as  to  be  unable  to 
withstand  the  normal  pressure.  Hemophiha  may  occur  during  the 
course  of  scurvy,  purpura,  leukemia,  etc.  When  such  a  diathesis  is 
present,  proper  measures  should  be  resorted  to  for  controlling  the 
heart's  action  and  increasing  the  coagulability  of  the  blood,  such  as  the 
administration  of  acetate  of  lead  in  two  grain  doses  every  two  hours, 
ornux  vomica,  or  aconite,  or  digitalis,  or  gaUic  acid,  or  chlorid  of  iron, 
or  the  following  formula: 

I^ — Infusi  digitalis,  5ii 

Ext.  ergotae,  fluidi, 

Tincturae  krameriae,  aa  3j 

Dose: — A  tablespoonful  as  required. 

Also  such  styptics  for  application  to  the  bleeding  cavity,  as  adrenalin 
chlorid,  tannic  acid,  antipyrin,  chlorid  of  iron,  powdered  subsulphate  of 
iron,  orthoform,  etc.  Extreme  debility  and  nervous  depression  have 
also  been  regarded  as  contra-indications  against  tooth-extraction, 
the  latter  often  resulting  from  dread  of  the  operation.  The  pain  of 
an  aching  tooth  may  sometimes  aggravate  the  symptoms  of  an  existing 
disease,  or  may  at  least  retard  recovery,  when  sedative  treatment  is 
indicated,  such  as  the  administration  of  bromid  of  potassium,  or 
sodium,  valerianate  of  ammonia,  etc.,  with  tonics. 

The  condition  of  the  membranous  tissue  of  the  mouth  must  also 
be    considered,    such    as    erysipelatous    inflammation,    for   example. 


428  THE  EXTRACTION  OF  TEETH. 

owing  to  its  tendency  to  spread  so  as  to  involve  the  glands  and  throat, 
as  a  result  of  tooth-extraction.  The  nervous  affection  known  as  epi- 
lepsy, characterized  by  convulsions  and  loss  of  consciousness,  the 
existence  of  which  is  generally  made  known  by  the  patient  prior  to  the 
operation,  has  also  been  named  as  one  of  the  contra-indications 
against  tooth-extraction;  but  from  the  fact  that  proper  precautions  can 
be  taken  to  guard  the  patient  against  any  injury  occurring  to  him  during 
the  existence  of  the  paroxysm,  this  affection  need  not  prevent  the  per 
formance  of  the  operation. 

The  extraction  of  the  deciduous  teeth  requires  so  little  force, 
owing  to  the  degree  of  physiological  absorption  of  both  their  roots  and 
alveolar  processes  at  the  period  when  their  removal  is  required,  that 
it  may  be  considered  a  simple  procedure.  Care,  however,  must  be 
taken  not  to  injure  the  developing  permanent  teeth  located  directly 
under  the  deciduous  ones.  The  greatest  difficulty  met  with  is  the 
task  of  gaining  the  consent  of  such  young  patients.  A  false  promise 
not  to  hurt  will  destroy  the  confidence  of  the  patient  in  the  veracity 
of  the  operator,  and  what  the  latter  may  gain  by  deception  at  one 
operation  will  only  increase  the  difficulty  at  a  subsequent  one.  The 
most  important  matter  connected  with  the  extraction  of  the  deciduous 
teeth,  is  for  the  operator  to  possess  an  accurate  knowledge  of  the 
order  in  which  nature  proposes  to  replace  these  teeth  with  the  per- 
manent ones;  for  in  no  instance  will  any  interruption  with  this  order 
be  tolerated,  without  such  results  occurring  as  the  irregular  arrange- 
ment of  the  teeth  of  the  permanent  set.  The  following  is  the  order  of 
eruption  of  both  the  deciduous  and  permanent  teeth: 

DECIDUOUS  TEETH.  PERMANENT   TEETH. 

Central  incisors    s  to  8  months                 First  molars  5  to    6  yeara 

Lateral  incisors    7  to  10    "                         Central  incisors  6  to    8 

First  molars        12  to  16    "                        Lateral  incisors  7  to    g 

Cuspids               14  to  20    "                        First  bicuspids  9  to  10 
Second  molars    20  to  36    "                        Second  bicuspids  10  to  12 

Cuspids  II  to  13 

Second  molars  12  to  14 

Third  molars  17  to  21 

The  -first  step  in  the  operation  of  tooth-extraction  is  to  make  a  care- 
ful examination  to  determine  the  location  and  condition  of  the  tooth 
to  be  removed,  its  relations  to  the  adjoining  teeth,  and  the  general 
state  of  the  mouth;  and,  if  an  anesthetic  agent  is  to  be  employed,  the 
systemic  condition  of  the  patient. 

The  second  step  is  to  select  the  proper  instruments  to  be  used  during 
the  operation.     The  third  step  is  to  determine  the  direction  in  which  the 


THE    EXTRACTION    OF    TEETH.  429 

force  it  is  necessary  to  employ  can  be  applied  in  the  line  of  least  re- 
sistance, owing  to  the  difference  in  anatomical  structure,  the  number 
of  roots,  the  class  of  tooth,  and  the  position  of  the  tooth  in  the  alveolar 
arch. 

The  operation  itself  may  also  be  divided  into  three  stages:  i.  The 
application  of  the  forceps  in  order  to  secure  a  firm  hold  on  the  tooth 
to  be  removed,  which  is  usually  the  upper  part  of  the  cervical  portion 
or  neck  (Fig.  283),  so  that  the  edges  of  the  beaks  of  the  instrument  may 
be  forced  between  this  part  of  root  and  the  margins  of  the  alveolus; 
for  by  thus  opening  the  orifice  by  expansion,  or  by  a  slight  fracture  of 
these  edges,  the  removal  of  a  normally  formed  tooth  is  greatly  facilitated. 

2.  The  application  of  the  required  degree  of  force  by  which  the 
pericemental  attachment  of  the  tooth  with  its  alveolar  cavity  is  loosened. 

3.  The  careful  removal  of  the  loosened  tooth  from  its  cavity,  and 
from  between  the  jaws  and  over  the  lips,  in  a  manner  that  w^ill  prevent 
injury  to  the  adjacent  teeth,  and  laceration  of  the  lips  by  the  ragged 
decayed  tooth  crown;  or  by  the  loosened  tooth  suddenly  leaving  its 
cavity,  as  in  the  case  of  a  lower  tooth,  and  the  forceps  fracturing  another 
in  the  opposite  jaw.  Hence,  the  lips  of  the  patient,  as  well  as  the 
fingers  of  the  left  hand  of  the  operator  holding  the  lips  open,  should  be 
protected  by  a  napkin.  Each  stage  of  the  operation  should  be  com- 
pleted before  beginning  the  succeeding  one,  and  no  movement  be  made 
by  the  forceps  more  rapidly  than  the  eye  can  follow.  In  performing 
this  operation,  the  object  should  be  the  removal  of  the  entire  tooth,  with 
as  little  mutilation  of  surrounding  soft  tissues  as  is  possible.  The 
application  of  three  forces  is  usually  regarded  as  necessary  in  ex- 
tracting, namely  traction,  rotation,  and  pressure;  "traction"  is  de- 
fined as  the  drav/ing  force,  "rotation"  is  the  turning  around  on  an 
axis  or  center;  "pressure"  is  the  force  exerted  by  one  body  on  another 
— applied  to  this  operation,  it  is  the  force  used  on  a  tooth  when  raising 
and  pushing  it  from  its  cavity. 

Position  0}  Operator  and  Patient. — ^The  position  of  the  operator  in 
performing  this  operation,  and  also  that  of  the  patient,  should  depend 
upon  the  teeth  to  be  extracted — whether  upper  or  lower  teeth;  whether 
the  teeth  are  on  the  right  or  the  left  side  of  the  mouth.  For  extracting  the 
upper  teeth,  the  operator  should  occupy  a  position  on  the  right  side  of 
the  patient,  whose  head  should  rest  in  the  depression  of  the  head-rest 
of  the  dental  chair,  the  back  of  w^hich  should  be  lowered  at  about  an 
angle  of  forty-five  degrees.  In  such  a  position  the  head  of  the  patient 
is  thrown  well  back,  being  encircled  by  the  left  arm  of  the  operator 
which  rests  on  the  edge  of  the  head-rest,  thus  giving  the  head  a  firm 


430  THE    EXTRACTION    OF    TEETH. 

support  by  pressure  against  his  breast.  The  fingers  of  his  left  hand 
are  used  to  distend  the  lips  of  the  patient,  and  also  to  retain  a  napkin 
in  place,  so  that  injury  of  the  lips  may  be  prevented  while  the  de- 
tached tooth  is  being  removed  from  between  them. 

For  extracting  the  upper  teeth  on  the  right  side,  the  position  of  the 
operator  should  be  to  the  right  and  a  little  to  the  front  of  the  patient, 
who  is  seated  in  the  dental  chair,  with  an  observance  of  the  directions 
already  given.  For  extracting  the  upper  teeth  on  the  left  side,  the 
position  of  the  operator  should  be  on  the  right  and  a  little  more 
to  the  front  of  the  patient,  than  for  the  teeth  on  the  right  side. 
For  extracting  the  lower  teeth,  the  operator  should  occupy  a  posi- 
tion on  the  right,  but  more  toward  the  rear,  of  the  patient,  with  the 
palm  of  his  left  hand  pressed  against  body  of  the  lower  jaw  over  the 
cheek,  his  fingers  over  the  body  of  the  lower  jaw,  and  his  thumb  de- 
pressing the  lower  Up,  and  assisting  in  supporting  the  jaw.  The 
back  of  the  dental  chair,  which  is  lowered,  should  be  almost  vertical, 
permitting  the  patient  to  assume  a  more  upright  position.  A  small 
stool  for  the  operator  placed  to  the  rear  of  the  chair,  wull  enable  him 
to  overreach  the  head  of  the  patient,  and  permit  his  having  more  com- 
mand of  his  right  arm  and  wrist. 

For  the  successful  removal  of  both  upper  and  lower  teeth,  it  is 
necessary  that  the  head  of  the  patient  should  be  so  firmly  supported 
that  the  entire  force  exerted  by  the  operator  should  be  borne  by  the  tooth, 
and  this  force  so  controlled  as  to  prevent  injury,  either  to  the  adjoining 
teeth,  or  to  those  in  the  opposite  jaw,  by  a  loosened  tooth  suddenly 
leaving  its  cavity. 

Instruments  Employed  for  the  Extraction  of  Teeth. — ^The  instru- 
ments employed  for  the  extraction  of  teeth  are  forceps,  elevators,  and 
the  screw.  There  are  special  recognized  forms  of  forceps  adapted  to 
the  different  classes  of  teeth,  and  also  other  forms  which  are  applicable 
to  teeth  presenting  abnormal  shapes  of  both  crowns  and  roots.  Per- 
haps the  best  rule  to  follow  is  for  the  operator,  after  some  experience, 
to  employ  those  forms  with  which  he  is  the  most  successful. 

The  early  dentists  employed  very  uncouth  instruments  for  extract- 
ing teeth,  and  the  now  almost  obsolete  turnkey  of  Garengeo  was  con- 
sidered to  be  a  great  improvement  on  the  extracting  instruments  that 
preceded  it.  This  instrument,  the  use  of  which  has  been  productive  of 
many  serious  accidents,  consists  of  either  a  straight  or  bent  shaft,  and 
two  or  more  hooks,  with  a  bolster  to  rest  upon  the  inner  surface  of 
the  gums  over  the  alveolar  cavity  of  the  tooth  to  be  extracted,  which 
forms  the  fulcrum.     After  the  use  of  the  lancet  to  separate  the  gums, 


THE    EXTRACTION    OF    TEETH.  43 1 

the  pointed  beaks  of  the  hook  are  firmly  attached  to  the  outside  sur- 
face of  the  neck  of  the  tooth,  the  handle  of  the  key  grasped  firmly  with 
the  right  hand,  and  the  tooth  raised  from  its  cavity  by  a  firm  and 
steady  rotation  of  the  wrist  of  the  operator.  With  the  improved 
instruments  used  at  the  present  time,  the  direction  of  the  force  is  in 
the  line  of  the  axis  of  the  tooth,  while  that  of  the  key  is  made  in  a  lateral 
direction  only. 

To  perform  the  operation  of  tooth-extraction  successfully,  the 
operator  should  be  provided  with  forceps  of  the  best  quality,  so  well 
tempered  that  the  beaks  will  spring  instead  of  fracture  under  the  force 
to  which  they  are  subjected,  and  so  shaped  as  to  permit  of  accurate 
adjustment  without  interfering  with  the  adjoining  teeth.  The  beaks 
should  also  be  so  curved  as  to  overreach  the  crowns  of  the  teeth  when 
their  edges  are  applied  to  the  necks,  and  thus  avoid  fractures  of  the 
crowns;  and  so  thin  and  sharp  that  the  use  of  the  gum  lancet  may 
be  dispensed  with  in  most  cases,  and  permit  of  the  edges  of  the 
beaks  being  introduced  between  the  gum  margin  and  the  thin  walls 
of  the  orifices  of  the  alveolar  cavities,  A  badly  adapted  forceps 
presents  to  the  surface  to  which  it  is  applied  but  one  or  two 
points,  which  prevent  the  application  of  the  necessary  traction. 
The  handles  of  these  instruments  should  be  wide,  and  of  such  a 
form  as  will  fit  the  hand  of  the  operator,  be  perfectly  rigid  when 
firmly  grasped,  and  serrated  on  their  outer  surfaces  to  prevent  slipping 
through  the  hand.  A  curve  on  the  end  of  one  of  the  handles  is  adapted 
to  the  little  finger  of  the  hand  holding  the  instrument,  and  materially 
assists  in  applying  the  required  force  in  the  case  of  firmly  implanted 
teeth.  The  manner  of  applying  and  using  the  forceps  may  be 
described  as  follows:  The  forceps  is  firmly  grasped  in  the  right 
hand  with  the  palm  of  the  hand  inward  and  the  thumb  on  the  top, 
with  its  ball  pressed  between  the  handles  in  the  bifurcation,  with  such 
force  as  will  regulate  and  limit  the  pressure  of  the  beaks  after  their 
edges  are  applied  to  the  portion  of  the  tooth  at  the  neck  to  be  grasped. 
By  using  the  ball  of  the  thumb  in  the  manner  described  an  increase  of 
the  pressure,  to  a  greater  degree  than  is  necessary,  on  the  tooth  may  be 
avoided  without  incurring  the  danger  of  crushing  it. 

The  first  or  second  finger  (according  to  their  length)  of  the  hand 
holding  the  forceps  should  be  inserted  between  the  handles  near  the 
bifurcation,  and  employed  for  separating  the  beaks,  and  also  to  assist 
in  maintaining  a  firm  hold  on  the  instrument.  The  little  finger  of 
the  right  hand  is  applied  to  the  curved  end  at  the  extremity  of  the 
outer  handle  of  the  forceps,   and,   with  the  serrated   outer  surface 


432 


THE    EXTRACTION    OF    TEETH. 


THE    EXTRACTION    OF    TEETH.  433 

of  the  handles,  will  prevent  the  instrument  from  slipping  through 
the  hand.  The  inner  beak  of  the  forceps,  when  applying  it  to 
the  neck  of  the  tooth,  should  be  placed  in  position  first,  then  the 
outer  beak,  care  being  taken  to  keep  these  beaks  clear  of  the  crown  of 
the  tooth,  and  thus  avoid  its  fracture;  then,  according  to  the  class  of 
tooth,  rotation,  or  the  outward  and  inward  motions  are  made  to  break 
the  attachment  of  the  tooth  to  its  alveolar  cavity.  In  some  cases, 
especially  of  frail  roots,  it  may  be  necessary  to  apply  forceps  with  cut- 
ting-edged circular  beaks  to  the  outside  of  the  outer  and  inner  walls 
of  the  alveolar  cavity  and  cut  through  such  walls,  in  order  to  obtain  a 
firmer  hold  on  the  stronger  portions  of  such  roots.  What  is  termed  "  a 
cultivated  sense  of  touch"  is  soon  acquired  by  the  operator,  when  the 
loosening  of  a  tooth  by  rotation,  or  the  outward  or  inward  motion" 
(according  to  the  class  of  tooth)  becomes  at  once  apparent;  or  its 
yielding  in  one  direction  only,  when  a  change  in  the  application  of  the 
traction  may  secure  its  removal  from  its  cavity  with  slight  effort. 
Cases  have  occurred  in  the  practice  of  the  writer  where  a  firmly  im- 
planted cuspid  tooth  has  resisted  all  efforts  to  remove  it,  to  such  a  degree 
as  to  render  it  dangerous  to  apply  greater  force,  when  the  postponement 
of  the  operation  to  the  following  day  has  resulted  in  its  easy  extraction, 
owing  to  the  effects  of  the  inflammation  excited  in  its  investing  mem- 
brane by  the  previous  attempt. 

After  applying  the  beaks  of  the  forceps  to  the  neck  of  the  tooth, 
they  should  not  be  pressed  together  more  tightly  than  is  necessary 
for  securing  and  maintaining  a  firm  hold;  otherwise  there  is  danger  of 
fracturing  the  tooth. 

Considering  the  different  classes  of  teeth,  the  following  rules  may  be 
formulated  for  their  removal  with  the  forceps:  Beginning  with  the 
upper  central  and  lateral  incisors,  which  may  be  grouped  together 
on  account  of  the  similarity  of  their  roots  and  environment,  the  force 
for  loosening  these  teeth  should  first  be  applied  in  the  direction  of  a 
line  drawn  through  the  greatest  axis  of  the  tooth  at  the  same  time  using 
rotation,  as  these  are  single  rooted  teeth  of  conical  form;  should  any 
portion  of  the  alveolar  walls  of  their  cavities  be  in  danger  of  removal 
by  the  strong  adhesion  of  their  roots,  the  rotary  motion  w^ill  loosen  it. 

In  all  cases  the  pressure  applied  should  be  labial,  for  the  reason 
that  it  is  in  the  line  of  least  resistance,  the  alveolar  process  on  the  labial 
aspect  being  thinner  than  on  the  lingual;  another  reason  is  that  pres- 
sure toward  the  lingual  causes  more  pain.  Labial  pressure,  when  not 
excessive,  will  enlarge  the  orifice  of  the  alveolar  cavity,  without  the 

danger  of  fracturing  the  margins  to  any  degree.     (Fig,  287.) 
28 


434 


THE    EXTRACTION    OF   TEETH. 


THE    EXTRACTION    OF    TEETH. 


435 


436  THE    EXTRACTION    OF    TEETH. 

For  the  extraction  of  the  upper  cuspids  a  considerable  degree  of 
traction  is  usually  necessary,  more,  perhaps,  than  for  any  other  teeth, 
as  these  teeth  have  the  longest  roots,  and  are,  as  a  rule,  firmly  implanted 
in  their  cavities.  The  traction  applied  should  be  in  the  labial  direction, 
as  this  is  in  the  line  of  least  resistance,  and  as  soon  as  an  impression 
is  made,  and  the  tooth  slightly  loosened  by  such  force,  then  slight  rota- 
tion will  assist  in  displacing  it;  the  rotary  motion  will  also  tend  to 
detach  any  portion  of  the  process  which  may  adhere  to  the  root,  as 
this  is  by  no  means  an  uncommon  occurrence.  The  rotary  movement 
should  be  applied  in  such  a  manner  that  the  labial  portion  of  the  tooth 
is  moved  toward  the  median  line,  from  the  fact  that  the  root  of  this 
tooth  frequently  has  a  direction  backward.  (Fig.  288.)  For  the  ex- 
traction of  the  upper  bicuspids,  traction  is  generally  employed.  In 
the  case  of  the  upper  first  bicuspid,  the  force  employed  should  be 
limited  in  degree,  as  this  tooth  has  usually  two  slender  roots  and  the 
process  over  the  buccal  root  is  thicker  than  over  the  root  of  the  cuspid, 
hence,  there  is  danger  of  fracturing  this  root  if  great  force  is  employed. 
On  this  account  the  force  should  be  carefully  applied,  and  in  the  lingual 
direction  to  a  greater  degree  than  in  the  buccal  direction.  The  second 
upper  bicuspid  has  usually  a  single  root  which  is  round  on  the 
buccal  and  lingual  surfaces,  and  flattened  on  the  mesial  and  distal 
surfaces,  the  root  being  disproportionately  long  compared  with  the 
circumference  of  the  neck.  For  the  extraction  of  this  tooth,  traction 
may  be  applied  in  the  line  of  least  resistance,  which  is  the  buccal — 
that  is  according  to  its  outward  inclination,  and  when  shghtly  loosened, 
the  rotary  motion  may  be  resorted  to  completely  displace  the  tooth. 
(Fig.  289.)  For  the  removal  of  the  upper  first  and  second  molars, 
which  may  also  be  grouped  together  on  account  of  similarity  in  form, 
position  and  environment,  traction  should  be  applied  first  in  a  buccal 
direction  according  to  the  outward  inclination  of  the  tooth,  for  the 
reason  that  the  resistance  is  first  offered  by  a  single  or  lingual  root, 
and  when  an  impression  is  made  upon  this  root,  that  of  the  two  buccal 
roots,  the  smaller  ones,  is  soon  overcome,  and  a  slightly  rotary  motion, 
although  the  roots  may  diverge  to  a  degree,  will  displace  the  tooth; 
the  process  is  also  thinner  on  the  buccal  aspect  than  on  the  lingual. 
Care  should  be  taken,  however,  not  to  make  the  buccal  pressure  too 
great,  for  in  such  a  case  considerable  fracture  of  the  buccal  wall  of  the 
process  may  result.  (Figs.  290,  291,  292  and  293.)  For  the  extraction 
of  the  upper  third  molars,  traction  should  be  made  downward  and  back- 
ward. The  roots  of  this  tooth  are  frequently  so  fused  together  as  to 
present  but  one  of  an  irregular  form,  which  permits  the  use  of  the  rotary 


THE    EXTRACTION    OF    TEETH. 


437 


438 


THE    EXTRACTION    OV    TEETH. 


1-1 


THE  EXTRACTION  OF  TEETH. 


439 


motion  in  the  direction  of  the  raphe  at  the  median  line  of  the  hard 
palate  or  roof  of  the  mouth.  These  teeth  being  the  last  in  the  upper 
arch,  and  near  the  tuberosity  of  the  process,  are  not  usually  very  firmly 
implanted,  especially  as  the  alveolar  process  surrounding  the  distal 
surfaces  of  their  necks  is  but  imperfectly  developed.  Hence  care 
should  be  taken  that  a  tooth  of  this  class,  when  loosened  by  the  forceps, 
does  not  escape  from  the  instrument,  and  slipping  down  the  throat 
enter  the  larynx  (Fig.  294) .  It  is  not  unusual  for  the  upper  third  molars 
to  erupt  on  the  outer  side  of  the  alveolar  ridge  with  their  occlusal  sur- 
faces directed  toward  the  cheek;  in  such  cases  the  direction  of  the  force 
should  be  outward  and  upward,  and  the  mutilation  of  the  tuberosity 
be  avoided  on  the  account  of  the  danger  of  penetrating  the  antrum, 
and  also  of  injuring  the  vessels  and  nerves  passing  through  the  tuberos- 
ity in  this  locality.  As  the  gum  tissue  at  the  distal  surface  of  these 
teeth  often  adheres  strongly  to  the  neck,  it  is  better  to  employ  the  gum 
lancet  to  sever  the  connection,  and  thus  avoid  the  danger  of  tearing  the 
gum.  The  form  of  lancet  represented  by  Fig.  310  (3)  answers  for 
such  cases. 

The  lower  teeth  are  usually  more  difficult  to  extract  than  the  upper 
ones,  especially  the  lower  third  molars  when  partly  erupted  or  impacted, 
owing  to  the  space  between  the  second  lower  molar  and  the  ascending 
ramus  of  the  jaw  not  being  sufficient  for  their  accommodation;  such  a 
difficulty  may  be  greatly  increased  when  the  patient  is  unable  to  open 
the  mouth  to  any  extent  owing  to  the  inflammation  incited  by  the  tooth 
itself  in  the  adjacent  tissues,  or  by  other  pathological  conditions,  such 
as  alveolar  abscess  for  example.  The  fact  that  the  inferior  maxillary 
bone  is  a  movable  one,  also  adds  to  the  difficulty  of  extracting  the  lower 
teeth,  as  it  is  necessary  for  the  operator  to  hold  the  jaw  immovably, 
by  placing  the  palm  of  his  left  hand  over  that  portion  of  the  cheek 
covering  the  body  and  border  of  the  bone,  his  fingers  under  the  jaws, 
and  his  thumb  pressing  down  the  lower  lip,  and  also  assisting  in  sup- 
porting the  jaw. 

The  external  oblique  line  extending  across  the  outside  surface  of 
the  lower  jaw,  from  near  the  mental  process  to  the  base  of  the  ramus 
and  the  mylo-hyoid  ridge  on  the  innersurfaceof  this  bone,  which  extends 
from  a  point  near  the  base  of  the  bone  at  the  median  line,  and  passes 
backward  and  upward  to  the  base  of  the  ascending  portion,  giving 
origin  to  the  mylo-hyoid  muscle  which  forms  the  greater  part  of  the 
floor  of  the  mouth;  both  of  these  prominences  add  to  the  thickness 
of  the  alveolar  ridge  over  the  roots  of  the  lower  molars,  and  increase 
the  difficulty  of  extracting  them;  this  is  especially  the  case  with  the 


440 


THE    EXTRACTION    OF    TEETH. 


THE    EXTRACTION    OF    TEETH. 


441 


442  THE    EXTRACTION    OF    TEETH. 

lower  third  molars,  when  their  roots  curve  posteriorly,  or  these  teeth 
are  but  partly  erupted,  or  impacted. 

For  extracting  the  lower  central  and  lateral  incisors  and  cuspids, 
these  teeth  having  single,  straight  and  mesio-distal  flattened  roots,  the 
operator  in  removing  them  occupies  a  position  a  little  back  on  the  right 
side  of  the  patient,  who  is  seated  more  uprightly  in  the  dental  chair 
than  for  the  removal  of  the  upper  teeth.  A  narrow  beaked  forceps 
is  employed  for  the  removal  of  the  lower  central  and  lateral  incisors, 
such  as  are  represented  by  Figs.  295  and  296,  and  the  outw-ard  and  in- 
ward motions  are  applied  with  a  force  sufficient  to  expand,  but  not  to 
fracture  to  any  degree,  the  orifices  of  their  alveolar  cavities. 

The  lower  cuspids,  being  larger  teeth,  and  more  firmly  implanted 
than  the  lower  incisors,  require  stronger  forceps  for  their  removal; 
hence,  the  lower  bicuspid  forceps,  represented  by  Fig.  297,  is  generally 
employed.  For  extracting  the  lower  first  and  second  bicuspids,  which 
have  generally  but  a  single  root,  which  is  straight,  tapering  gradually 
from  the  neck  to  the  apex,  that  of  the  second  being  larger  and  longer 
than  that  of  the  first  bicuspid,  the  motion  required  should  be  out- 
wark  and  inward,  accompanied  with  a  slight  rotary  motion  as  the  tooth 
is  yielding,  to  assist  in  detaching  the  process  from  the  root.  (Fig.  298.) 
For  extracting  the  lower  first  and  second  molars,  the  outward  and 
inward  motions  should  be  made;  the  roots  of  these  teeth,  two  in  num- 
ber, usually  diverge  and  stand  across  the  alveolar  ridge,  being  situated 
immediately  beneath  the  mesial  and  distal  halves  of  the  crowns. 

They  are  flattened  on  their  mesial  and  distal  surfaces,  and  broad 
at  the  neck  from  the  buccal  to  the  lingual  surfaces;  the  mesial  root  usu- 
ally being  somewhat  larger  and  longer  than  the  distal  root.  The  instru- 
ments adapted  for  their  removal  are  illustrated  by  Figs.  299  and  300. 
The  points  on  the  concave  edges  of  beaks  of  this  forceps  should  be 
inserted  in  the  space  between  the  roots  on  each  side  of  the  alveolar 
ridge,  the  concave  surfaces  grasping  the  convex  surfaces  of  the  roots. 
Care  should  be  taken  when  applying  the  forceps  that  no  part  of  the 
tongue  be  inclosed  between  the  beaks  and  the  roots;  the  danger  of  a 
lower  molar  suddenly  leaving  its  cavity  after  being  loosened,  and  the 
forceps  fracturing  teeth  in  the  opposite  jaw  should  be  guarded  against. 
Some  prefer  to  apply  the  first  force,  in  loosening  these  teeth,  in  the 
direction  of  the  inclination  of  the  tooth  in  its  cavity,  either  outward  or 
inward.  When  the  two  roots  of  a  lower  molar  diverge  greatly  it  may 
become  necessary  to  use  the  splitting  forceps  represented  by  Fig.  301, 
the  sharp  edges  of  which  are  carried  down  over  the  crown  to  the  space 
between  the  roots,  and  the  crown  divided  at  the  center  of  the  buccal 


THE    EXTRACTION    OF    TEETH. 


443 


444 


THE    EXTRACTION    OF    TEETH. 


and  lingual  surfaces,  using  a  strong  pair  of  root  forceps  to  remove  each 
root  thus  separated.  The  extraction  of  a  lower  second  molar  is 
usually  an  easier  operation  than  that  of  a  first  molar,  for  the  reason 
that  the  roots  of  the  second  do  not  diverge  from  the  neck  to  the  same 
degree.  The  extraction  of  the  lovi^er  third  molar,  when  the  teeth 
occupying  the  arch  are  not  unusually  large,  or  irregular  in  position,  is 
not  difficult  and  can  be  accomplished  by  the  forceps  represented  by 
Fig.  302.  The  outward  and  inward  motions  are  usually  employed  for 
loosening   the   lower  third  molars,  except  in  cases  where,  owing  to 


11  i- 


Fig.  303. — Deciduous  Teeth  lorceps. 


rriegularity  in  position,  it  may  be  better  to  apply  the  first  force  accord- 
ing to  the  outward  or  mw  ard  inclination  of  the  tooth. 

The  operator  and  patient  occupy  the  same  positions  in  the  extrac- 
tion of  both  the  lower  first  and  second  molars.  When  the  force  it 
would  be  necessary  to  use  in  attempting  to  extract  an  abnormally 
shaped,  or  located  lower  third  molar  would  endanger  the  bone  of  the 
jaw,  and  especially  when  there  is  a  backward  curvature  of  the  root, 
it  is  better  to  cut  away  the  process  with  a  bone-cutting  bur,  operated 
by  the  dental  engine,  until  a  sufficient  portion  of  the  root  is  exposed 
to  be  grasped  by  the  forceps;  this  method  can  also  be  followed  in  the 
case  of  hypercementosed  roots  of  other  teeth;  also  in  cases  of  partly 


THE    EXTRACTION    OF   TEETH. 


445 


m 


<d)j) , 


u 


o 


I  m  iniu 


<o 


446 


THE    EXTRACTION    OF    TEETH. 


THE  EXTRACTION  OF  TEETH. 


447 


erupted,  and  impacted  teeth.  In  loosening  abnormal  lower  third 
molars,  the  direction  of  the  force  applied  should  be" outward,  backward, 
and  upward.  What  is  known  as  the  elevating  forceps  is  also  employed 
for  the  extraction  of  partially  erupted  lower  third  molar  teeth,  the 
pointed  ends  of  the  beaks  being  applied  in  the  space  between  such  a 
tooth  and  the  second  molar,  the  latter  tooth  being  used  as  a  fulcrum. 
When  a  secure  hold  is  obtained,  the  handles  of  the  instrument  are 
depressed  and  the  abnormally  placed  tooth  is  forced  from  its  cavity, 
or  so  loosened  that  it  can  be  readily  seized  with  the  root  forceps. 
After  extracting  any  class  of  tooth,  the  expanded  margins  of  the  alveolar 


Fig.  308. 

cavity  should  be  gently  pressed  together  with  the  thumb  and  forefinger. 
As  a  preventive  against  hemorrhage,  and  the  after-pain  of  extraction, 
it  has  been  recommended  to  fill  the  cavity  from  which  the  tooth  has 
been  removed  with  powdered  orthoform,  or  to  apply  a  solution  of  phenol 
sodique  on  a  pledget  of  cotton. 

The  Extraction  0}  Deciduous  Teeth.— The  extraction  of  the  decidu- 
ous teeth  is  performed  in  the  same  manner  as  those  of  the  permanent 
teeth,  smaller  and  fewer  instruments,  however,  being  required.  Fig. 
303  represents  a  set  of  three  forms  of  small  forceps  suitable  for  the  re- 
moval of  the  deciduous  teeth,  although  many  operators  employ  the 


448 


THE    EXTRACTION    OF    TEETH. 


smaller  beak  forceps  of  the  permanent  teeth  instruments,  especially 
the  root-forceps,  for  the  removal  of  such  teeth.  Less  force  is  required 
for  the  extraction  of  the  deciduous  teeth  for  reasons  before  given,  but 
it  is  necessary  that  care  should  be  taken  that  the  operation  is  per- 
formed in  such  a  manner  that  the  developing  permanent  teeth,  or  their 
A  crypts,  are  not  injured.  In  some  instances 
the  developing  crown  of  a  bicuspid  has 
been  brought  away  in  extracting  a  deciduous 
molar,  owing  to  the  position  of  the  crown 
of  the  former  tooth  between  the  unabsorbed 
roots  of  the  latter. 

The  Extraction  of  Roots  of  Teeth. — ^The 
extraction  of  roots  is  sometimes  a  difficult 
operation,  but  usually  they  are  more  easily 
removed  than  entire  teeth,  especially  when 
they  have  remained  in  the  alveoli  for  a  con- 
siderable time  after  the  loss  of  their  crowns, 
and  have  not  become  exceedingly  fragile 
from  decay.  When  long  retained,  the  at- 
tachment of  roots  becomes  weakened  by 
their  loss  of  substance  and  absorption  of 
their  cavities,  together  with  the  deposition 
of  bone  at  the  apexes  of  their  cavities  to 
such  a  degree  as  to  render  their  removal 
easy,  as  they  are  held  in  position  simply  by 
their  connection  with  the  gum.  It  often 
becomes  necessary,  however,  to  extract 
firmly  implanted  roots,  owing  to  their  sepa- 
ration from  the  crowns  when  attempting  to 
extract  the  entire  tooth,  and  great  difficulty 
is  often  encountered,  and  to  such  a  degree 
as  to  render  it  necessary  to  use  special  in- 
struments devised  for  these  cases.  The 
instruments  employed  for  the  extraction  of 
roots  are  known  as  root-forceps,  and  eleva- 
tors, and,  as  a  general  rule,  these  root  forceps  have  long  and  slender 
beaks,  which  are  not  adapted  for  the  application  of  great  force;  hence 
the  movements  made  with  them  should  be  gentle,  as  well  as  effective. 
Figs.  304,  305,  and  306  represent  useful  forms  of  root-forceps.  Figs. 
304  and  305  are  designed  by  Dr.  M.  H.  Cryer  for  the  extraction  of 
any  single-rooted  tooth,  and  for  third  molars,  and  frail  lower  incisors. 


llG.   309. 


THE    EXTRACTION    OF    TEETH. 


449 


The  slender  beak  bayonet-shaped  forceps,  devised  by  Dr.  B.  F. 
Arrington,  and  represented  by  Fig.  306,  is  a  useful  instrument  for 
difficult  upper  roots. 

Fig.  308  represents  the  common  forms  of  elevators.  In  using  the 
elevator,  care  is  necessary  that  the  instrument  does  not  slip  and  wound 
the  mouth  of  the  patient. 

In  the  employment  of  the  elevator,  an  adjoining  tooth  or  root,  if 
present,  is  used  as  a  fulcrum;  in  other  cases,  the  thumb  of  the  hand  of 
the  operator  holding  the  instrument  may  be  thus  used.  The  point  or 
edge  of  the  blade  of  the  elevator  is  inserted  between  the  root  to  be  re- 
moved and  the  adjoining  tooth  or  root,  and  by  a  slight  rotary  motion  the 


Fig.  310. 


root  is  forced  from  its  cavity.  An  instrument  in  the  form  of  a  screw  is 
also  used  for  the  extraction  of  frail  roots,  and  single-rooted  teeth. 
(Fig.  309.)  Before  the  screw  is  introduced  into  the  root,  the  walls  of 
which  have  become  greatly  funneled  out  by  decay,  so  as  to  render  them 
incapable  of  sustaining  the  pressure  of  the  forceps,  the  exposed  surface 
of  the  root  should  be  reamed  out  to  remove  the  soft,  decomposed 
matter,  and  thus  a  sufficiendy  firm  hold  for  the  screw  be  secured.  The 
screw  is  then  carefully  inserted  by  half-turns  until  it  obtains  a  firm 
hold  in  the  root,  and  force  in  the  line  of  the  axis  of  the  root  is  then 
applied,  and  its  extraction  accomplished.  The  screw,  after  it  is  se- 
curely fixed  in  the  root,  may  be  detached  from  its  handle  and  the 
beaks  of  a  forceps  applied  to  the  root,  the  screw  within  affording  sup- 
port, and  the  frail  root  be  successfully  extracted. 
29JJ 


450 


THE    EXTRACTION    OF    TEETH. 


Gum  Lancets. — ^The  use  of  the  lancet,  when  necessary,  precedes  the 
application  of  the  forceps  for  the  purpose  of  separating  the  adherent 
gum  tissue  at  the  necks  of  the  teeth.  The  form  of  forceps 
as  at  present  constructed,  with  thin  sharp-edged  beaks, 
renders  the  use  of  the  lancet  only  necessary  where  there 
is  a  risk  of  laceration  or  tearing  the  soft  tissues  sur- 
rounding the  tooth  or  root  to  be  extracted;  in  the  case 
of  deeply  imbedded  roots,  and  third  molar  teeth,  and 
teeth  standing  alone,  the  gum  lancet  may  be  advanta- 
geously employed.  Fig.  310  represents  useful  forms  of 
lancets,  and  Fig.  311  an  all-metal  lancet  which  is  capable 
of  being  effectually  sterilized.  Fig.  310  (3)  represents 
a  useful  lancet  for  separating  the  gum  tissue  from  the 
posterior  surface  of  the  neck  of  a  third  molar  tooth. 

Fig.  310  (5)  represents  a  useful  form  of  lancet  for 
liberating  erupting  deciduous  teeth,  opening  abscesses, 
and  performing  other  surgical  operations.  The  manner 
of  using  the  gum  lancet  when  extracting  teeth  is  as  fol- 
lows: The  sharp  edge  of  the  blade  is  pressed  against 
the  neck  of  the  tooth  and  within  the  free  edge  of  the 
gum,  and  passed  around  the  inner  and  outer  surfaces  of 
the  neck  as  deeply  as  possible,  after  which  the  blade  of 
the  instrument  is  inserted  in  the  interproximal  spaces 
anterior  and  posterior  to  the  tooth  to  be  extracted.  By 
such  a  method  the  membranous  attachment  of  the  tooth 
at  its  cervical  portion  is  completely  severed,  and  a  way 
is  made  for  inserting  the  edges  of  the  beaks  of  the 
forceps;  the  danger  of  the  slipping  of  the  lancet  is  also 
avoided  by  applying  the  edge  at  an  angle  to  the  neck, 
and  a  secure  hold  upon  the  tooth  obtained  with  the 
forceps.  When  extracting  the  deciduous  teeth,  the  use 
of  the  gum  lancet  is  unnecessary  and  at  the  same  time 
injudicious,  for  the  reason  that  these  teeth  are  less  firmly 
implanted  than  the  permanent  teeth,  the  process  about 
them  being  softer  and  more  yielding,  and  at  the  period 
when  their  removal  is  necessary  their  roots  are  so  much 
absorbed  and  their  attachment  to  the  alveolar  cavity  is 
so  greatly  weakened  that  but  little  force  is  required  to 
detach  them.  The  employment  of  the  lancet  in  the  case 
of  the  deciduous  teeth  is  also  injudicious,  for  the  reason 
that  the  pain  caused  by  this  instrument  may  be  such  as  to  prevent  a 


Fig.  311. 


THE    EXTRACTION    OF    TEETH.  45 1 

further  continuance  of  the  operation  without  force  is  employed  on  the 
patient,  which  is  always  unpleasant  and  to  be  avoided  if  possible. 

The  Casualties  Attending  Tooth-extraction. — ^The  operator  should 
at  all  times  be  prepared  to  avert  and  also  to  successfully  meet  the 
dangers  attending  tooth-extraction,  which  may  be  enumerated  as 
follows:  The  fracture  of  the  whole  or  a  portion  of  the  crown  of  the 
tooth  is  the  most  frequent  accident  occurring  during  this  operation, 
and  may  be  occasioned  by  an  ill- adapted  instrument  being  used;  by 
its  improper  application;  by  too  much  force  being  applied,  and  too 
forcible  movements  made  in  loosening  the  tooth.  This  accident  may 
sometimes  be  unavoidable,  and  when  such  is  apparent  it  is  better  to 
inform  the  patient  of  its  probability. 

The  extraction  of  the  wrong  tooth  may  occur  as  the  result  of  failure 
to  make  a  careful  preliminary  examination;  or  from  an  incorrect  diag- 
nosis; or  from  carelessness  in  applying  the  forceps,  especially  when 
the  teeth  are  crowded.  If  the  conditions  are  favorable,  replantation 
may  be  resorted  to. 

Fracture  of  the  alveolar  process  may,  to  a  limited  degree,  and  where 
it  involves  the  margins  of  the  alveoli  only,  be  a  common  necessity  in 
extraction,  but  in  no  case  should  the  fracture  be  so  extensive  as  to  cause 
serious  injury. 

Fracture  of  the  jaws  is  not  probable  when  using  the  forceps  as  at 
present  constructed,  without  excessive  and  unnecessary  force  is  em- 
ployed, or  the  bone  is  in  a  diseased  condition. 

A  sound  tooth  may  be  extracted  when  it  is  joined  by  a  cemental 
fusion  with  the  roots  of  another  requiring  removal,  and  in  such  a  case 
may  be  an  unavoidable  accident. 

The  escape  of  a  posterior  tooth  or  root  into  the  larynx  or  pharynx 
may  occur  when  a  tooth,  such  as  a  third  molar,  suddenly  leaves  its 
cavity  and  escapes  from  the  forceps  during  the  operation  of  extracting 
it.  If  the  fingers  cannot  remove  the  tooth,  resort  may  be  had  to  the 
pharyngeal  forceps. 

Dislocation  of  the  lower  jaw  is  an  accident  only  likely  to  occur 
from  a  laxity  of  the  ligaments  of  the  temporo-maxillary  articulation, 
due  to  a  previous  luxation  from  any  cause. 

Syncope  or  fainting  is  a  common  and  unavoidable  accident  attend- 
ing tooth-extraction.  In  such  a  case  the  patient  should  be  placed  in  a 
horizontal  position  by  lowering  the  back  of  the  chair  to  such  a  degree 
that  the  feet  are  elevated,  and  the  blood  gravitates  to  the  brain.  Stimu- 
lation by  wine,  whiskey  or  brandy,  or  the  aromatic  spirits  of  ammonia, 
in  doses  of  half  a  dram  in  half  a  wine-glass  of  water,  will  increase 


452  THE  EXTRACTION  OF  TEETH. 

the  heart's  action;  rubbing  and  slapping  the  hands,  or  the  application 
of  cold  water  to  the  face  and  breast,  may  also  prove  effective;  after 
which  the  patient  should  be  kept  at  rest  for  some  time. 

Shock  during  tooth-extraction  is  often  confounded  with  syncope, 
and  as  far  as  the  ordinary  symptoms  of  this  latter  condition  extend, 
these  two  are  analogous  and  differ  in  degree  and  duration  more  than 
in  character.  In  shock  there  is  a  state  of  prostration,  a  pallor  of  the 
whole  surface,  pale  and  bloodless  lips,  a  loss  of  luster  in  the  eyes,  the 
eyeball  partially  concealed  by  the  drooping  upper  eyelid,  dilated  nos- 
trils, a  cold,  clammy  moisture  often  gathered  in  beads  upon  the  fore- 
head, a  low  temperature,  weakness  of  muscles,  bewildered  mind,  often 
insensibility,  and  there  may  be  nausea  and  vomiting.  The  aged  are 
slower  in  recovering  from  the  effects  of  shock  than  the  young,  although 
they  have  more  power  of  resistance;  in  the  young  the  impression  is 
more  easily  made,  but  subsides  sooner  than  in  the  old.  The  treatment 
of  shock  consists  in  placing  the  patient  flat  on  the  back,  and  the  use 
of  such  stimulants  as  brandy,  or  aromatic  spirits  of  ammonia,  in  the 
same  doses  as  for  syncope.  Heat  applied  to  the  epigastrium  by  means 
of  flannel  wrung  out  in  hot  water,  or  the  hot  water  rubber  bag,  and 
mustard  plasters  are  beneficial.  Small  chips  of  ice  swallowed  whole 
will  allay  the  nausea  and  vomiting. 

Forcing  teeth  or  roots  into  the  antrum  in  the  endeavor  to  extract 
them,  especially  when  the  alveolus  communicates  with  this  cavity  owing 
to  absorption  occasioned  by  the  action  of  pus.  In  such  a  case,  the 
orifice  of  the  opening  into  the  antrum  should  be  enlarged,  and  the  tooth 
or  root  removed  with  the  pharyngeal  forceps. 

The  mutilation  of  the  maxillary  tuberosity  in  extracting  an  upper 
molar  should  always  be  avoided,  as  severe  hemorrhage  may  result 
from  the  rupture  of  the  posterior  dental  artery,  which  may  be  difficult 
to  control;  also  injury  to  the  palatine  branches  of  nerves;  in  some  cases 
deafness  has  been  ascribed  to  such  an  accident;  also  an  opening  into 
the  antrum,  as  a  result  of  the  mutilation  of  the  tuberosity.  When  the 
fracture  of  the  tuberosity  is  slight,  the  parts  may  be  pressed  together  by 
the  thumb  and  finger  to  control  the  hemorrhage  when  it  is  severe,  and 
the  parts  packed  with  medicated  gauze,  which  should  remain  for 
several  days  before  removal. 

Alveolar  hemorrhage  from  the  extraction  of  a  tooth  may  result 
from  the  condition  of  the  parts  involved,  such  as  the  character  of  the 
blood,  which  is  shown  by  want  of  coagulability;  also  from  diseased 
walls  of  the  vessels,  and  inflammation  in  the  adjacent  tissues;  and 
finally  from  the  predisposition  of  the  patient,  as  in  hemophilia.     To 


THE  EXTRACTION  OF  TEETH.  453 

determine  whether  the  blood  is  coagulable,  a  small  quantity  may  be 
caught  in  a  vessel,  and  if  it  forms  a  clot  in  the  course  of  two  or  three 
minutes  much  cause  for  alarm  is  removed,  and  the  line  of  treatment 
sufficiently  clear,  as  the  diagnosis  may  indicate  the  cause  to  be  either 
vascular  or  mechanical.  A  failure  in  the  contraction  of  the  mouths 
of  the  bleeding  vessels,  or  adhesion  of  the  vessels  to  the  walls  of  the 
surrounding  bony  canal,  or  the  rupture  of  an  abnormally  large  vessel 
may  also  be  causes  of  alveolar  hemorrhage.  Usually  the  hemorrhage 
after  the  extraction  of  teeth  ceases  within  one  hour,  although  a  slight 
oozing  may  continue  longer,  and  does  not  require  treatment;  if  it 
should  be  more  prolonged,  as  the  result  of  great  inflammation  in  the 
adjacent  parts,  or  the  patient  is  anemic,  or  predisposed  to  the  hemor- 
rhagic diathesis  (hemophilia),  treatment  for  its  arrest  is  required. 

For  the  arrest  of  alveolar  hemorrhage  (arterial),  such  styptics  are 
useful  as  tannic  acid,  gallic  acid,  iodoform  gauze,  alum,  nitrate  of 
silver,  perchlorid  or  persulphate  of  iron  (either  of  w^hich  may  be  used 
in  solution  or  powder) ,  or  carbolized  resin  (resin  and  phenol  in  chloro- 
form), or  adrenalin  chlorid,  or  styptic-colloid  (a  combination  of  tannic 
acid,  collodion,  and  tincture  of  benzoin),  or  orthoform.  The  prepara- 
tions of  iron  and  nitrate  of  silver  are  considered  objectionable  on  ac- 
count of  the  clot  formed  by  them  being  soluble  in  the  blood,  and  the 
escharotic  action  of  the  nitrate  of  silver  not  being  limited  to  the  alveolar 
cavity,  and  the  surface  of  the  wound  thus  extended. 

The  local  treatment  consists  in  first  removing  the  clotted  blood  from 
the  cavity,  and  this  is  especially  necessary  in  case  of  secondary  hemor- 
rhage, where  the  clot  may  be  found  protruding  from  the  vacant  cavity, 
and  in  some  cases  almost  filling  the  mouth.  After  the  removal  of  the 
clot,  the  alveolar  cavity  should  be  syringed  wdth  ice-cold  water,  to  which 
is  added  a  small  quantity  of  phenol  sodique  (phenate  of  soda),  and  a 
pledget  of  cotton  or  lint  saturated  with  the  styptic  applied  to  the  apex 
of  the  cavity  and  over  the  mouth  of  the  bleeding  vessel. 

Dry  absorbent  cotton  is  then  introduced  over  the  styptic,  and 
firmly  condensed,  so  that  the  cavity  is  tightly  filled  to  and  a  little  be- 
yond its  orifice.  In  severe  cases  of  alveolar  hemorrhage,  a  compress 
is  a  valuable  adjunct,  in  order  to  increase  the  pressure  on  the  cotton 
plug,  filling  the  cavity.  Such  a  compress  may  consist  of  a  cork  with 
a  concave  end  to  fit  over  the  cotton  plug,  and  of  such  a  length  as  will 
permit  the  opposing  teeth  to  press  against  it  with  some  force;  or  it 
may  consist  of  either  semiplastic  gutta-percha,  or  modeling  com- 
pound; tannic  acid,  or  other  styptic,  is  incorporated  in  the  gutta-percha, 
a  plug  of  which  is  held  by  the  pliers  for  a  short  time  in  hot  water  to 


454  THE    EXTRACTION    OF    TEETH. 

soften  it,  and  after  the  bleeding  cavity  is  dried  with  hot  absorbent 
cotton,  the  warm  styptic  plug  is  firmly  pressed  to  the  bottom  of  the 
cavity,  and  held  there  until  it  hardens;  also  bathing  the  root  of  the 
extracted  tooth,  when  it  is  a  single  root,  with  the  styptic  and  returning 
it  to  its  cavity;  also  a  plug  of  half  hardened  plaster  of  Paris;  also  when 
the  hemorrhage  occurs  from  the  cavities  of  several  teeth,  a  plaster 
impression  of  the  mouth,  or  a  part  of  it,  taken  in  the  ordinary  manner, 
and  allowed  to  remain  in  position  for  some  time  before  attempting 
its  removal.  Other  mechanical  styptics  such  as  matico  leaf,  spider's 
web,  burnt  cork,  puff-ball,  powdered  resin,  etc.,  have  been  suggested. 
When  matico  leaf  is  employed,  the  fresh  leaf  is  preferable,  or  if  in  a 
dry  state  it  may  be  moistened  with  water  and  then  rolled  into  a  con- 
venient form,  with  the  rough  side  outward  and  forced  into  the  cavity. 
Packing  the  cavity  with  cotton  moistened  with  Canada  balsam  is  also 
recommended,  as  it  does  not  require  any  prolonged  pressure.  Car- 
bolized  resin  may  be  applied  on  a  saturated  strip  of  the  fungus  amdou. 

The  plugs  containing  the  styptic  should  be  retained  in  position  for 
from  24  to  48  hours  and  then  be  cautiously  removed ;  and  if  a  compress 
is  applied,  the  jaws  should  be  secured  and  continuous  pressure  main- 
tained by  a  four-tailed  bandage  passed  from  the  chin  over  the  head. 
During  the  treatment  the  patient  should  be  kept  at  rest,  and  abstain 
from  the  use  of  hot  fluids,  alcohol,  and  tobacco,  as  they  relax  the  ar- 
teries, and  favor  a  return  of  the  hemorrhage.  In  connection  with  the 
styptic,  and  in  cases  where  the  hemorrhage  has  resulted  from  the  ex- 
traction of  a  tooth  or  root  which  has  been  held  in  place  only  by  gum 
tissue,  and  the  cavity  after  extraction  is  of  little  depth  wherein  to  pack 
the  styptic,  the  following  internal  remedy  has  been  suggested  by  Dr. 
W;  L.  Robinson,  and  can  be  administered  with  benefit:  Three  grains 
of  tannic  acid  dissolved  in  one- third  of  a  tumbler  of  water;  two  tea- 
spoonfuls,  to  be  given  every  five  minutes  until  three  doses  are  taken, 
after  which  the  same  quantity  is  given  every  fifteen  minutes.  When 
such  measures  as  have  been  referred  to  for  the  arrest  of  alveolar  hemor- 
rhage fail,  resort  may  be  had  to  the  cautery,  either  the  galvano  cautery, 
or  the  Paquelin  benzoline  cautery. 

The  after-pains  of  extraction  when  due  to  pericementitis,  or  any  form 
of  septic  infiltration,  may  be  relieved  by  either  filling  the  vacant  cavity 
with  a  pledget  of  cotton  soaked  with  phenol  sodiqup,  or  with  a  solution 
composed  of  glacial  carbolic  acid,  §j,  liq.  potassae,  §j,  and  water 
Bviij;  or  by  applying  to  such  a  cavity  one  drop  of  a  one  per  cent  solu- 
tion of  nitro-glycerin  in  half  a  wine-glass  of  cold  water;  or  a  five  per 
cent  solution  of  equal  parts  of  cocain  and  iodoform.     If  such  local 


THE  EXTRACTION  OF  TEETH.  455 

applications  fail,  a  solution  of  one-eighth  of  a  grain  of  morphine  may 
be  injected  into  the  gum  over  the  vacant  cavity. 

The  ajter-treatment  of  extraction  is  often  of  great  benefit  to  the 
patient.  In  ordinary  cases  the  use  of  a  twenty  per  cent  solution  of 
phenol  sodique  is  of  great  service,  or  a  three  per  cent  aqueous  solution 
of  pyrozone,  especially  if  the  case  has  been  one  of  pericementitis  or 
alveolar  abscess;  either  of  these  antiseptic  solutions  may  be  used  as  a 
mouth  wash,  and  the  mouth  rinsed  for  several  days.  Filling  the  cavity 
with  powdered  orthoform,  as  soon  as  the  bleeding  has  subsided,  is  also 
beneficial.  Where  an  alveolar  abscess  has  existed  for  some  time 
previous  to  the  extraction  of  the  tooth,  and  the  process  has  to  a  degree 
become  necrosed,  the  cavity  should  be  syringed  with  a  solution  of  ten 
grains  of  either  the  sulphate  or  the  iodid  of  zinc,  which  will  separate 
the  dead  from  the  living  portion  of  the  bone,  forming  a  sequestrum. 

When  extracting  teeth  a  careful  observance  of  the  rule  before  re- 
ferred to,  namely,  "that  no  movement  should  be  made  with  the 
forceps  faster  than  the  eye  can  readily  follow,"  may  prevent  the  oc- 
currence of  accidents  liable  to  attend  this  operation — namely,  serious 
fractures,  te  aring  the  gums,  etc.  Should  the  gum  adhere  so  firmly  to 
the  process  that  it  begins  to  tear  away,  the  operation  should  be 
suspended  until  the  attachment  is  severed  by  the  lancet  or  curved 
scissors. 

Sterilizing  Instruments. — The  absolute  sterilization  of  operating 
instruments,  such  as  forceps,  etc.,  is  demanded,  inasmuch  as  infected 
matter  is  much  more  readily  communicated  by  them  through  wounds 
than  by  the  fingers  of  the  operator.  Sterilization  is  so  easily  accom- 
plished that  there  is  no  excuse  for  neglecting  it.  A  simple  and  effective 
method  is  by  immersing  the  instruments  in  boiling  water  to  which  one 
or  two  per  cent  of  carbonate  of  soda  has  been  added  to  prevent  rusting. 
Five  minutes  immersion  in  such  a  solution  will  answer  for  forceps 
and  three  minutes  for  smaller  instruments,  unless  they  have  become 
coated  with  a  thick  dry  coat  of  infectious  matter,  when  a  longer  boiling 
is  required,  and  a  subsequent  immersion  in  a  one  to  thirty  per  cent, 
solution  of  phenol.  Lysol  may  be  substituted  for  the  phenol  as  it 
will  not  rust  the  instruments,  and,  hence,  does  not  require  the  use  of  a 
solution  of  soda.     Trichlorphenol  is  also  an  efficient  sterilizing  agent. 

The  strictest  aseptic  and  antiseptic  precautions  should  be  ob- 
served when  operating  on  the  mouth. 

The  extraction  of  teeth  under  the  influence  of  anesthetic  agents 
has  become  so  general,  and  there  are  so  few  cases  in  which  either  a 
local  or  a  general  anesthetic  is  not  admissible,  that  a  writer  on  this 


456  THE  EXTRACTION  OF  TEETH. 

subject  has  declared  it  to  be  an  almost  barbarous  procedure,  when 
performed  without  the  aid  of  such  an  agent. 

The  operator  should,  however,  in  all  cases  be  governed  by  the 
condition  of  the  patient,  which  can  be  determined  by  a  physical  ex- 
amination. Local  anesthetic  agents  applied  by  the  hypodermic 
method  are  employed  to  obviate  the  dangers  of  general  anesthetics, 
which  are  administered  by  inhalation.  When  using  the  hypodermic 
method,  several  dangers  are  to  be  avoided:  i.  The  needle  of  the 
syringe  should  not  penetrate  a  vein,  as  the  entire  dose  may  be  carried 
to  vital  centers;  hence,  a  locality  should  be  selected  for  puncturing  that 
is  free  from  veins,  nerves,  and  large  blood  vessels;  the  vascular  and 
soft  structures  of  the  cheeks  beyond  the  gum  should  also  be  avoided. 

2.  Both  the  needle  of  the  syringe,  and  the  anesthetic  solution, 
should  be  rendered  sterile  before  using;  otherwise  an  abscess  may 
result  from  infection.  The  direct  application  of  a  strong  solution 
of  the  anesthetic  agent  to  be  used  to  the  area  of  the  gum  into  which  the 
needle  is  to  be  inserted,  will  enable  the  puncturing  to  be  made  without 
pain. 

The  selection  of  a  general  anesthetic  agent,  when  one  is  preferred, 
should  be  governed  by  the  condition  of  the  patient  and  the  nature 
of  the  operation;  and  the  physiological  action  of  the  agent  employed 
should  be  well  understood 

A  combination  of  nitrous  oxid  and  oxygen,  although  transient  in 
its  effects,  may  answer  for  the  majority  of  cases  of  tooth-extraction, 
especially  when  few  teeth  are  to  be  removed;  while  in  other  more  pro- 
longed operations,  as  the  extraction  of  a  number  of  teeth  and  roots, 
sulphuric  ether  may  be  preferable;  or  after  anesthetization  by  nitrous 
oxid,  the  effects  may  be  continued  by  the  inhalation  of  ether.  For 
the  physiological  action  of  the  different  anesthetic  agents,  and  the 
manner  of  their  administration,  the  student  should  consult  authorities 
on  this  subject.  Before  extracting  teeth  under  the  influence  of  an 
anesthetic  agent,  the  operator  should  be  prepared  to  meet  all  dangerous 
symptoms  liable  to  occur.  Restoratives,  such  as  aqua  ammonia  for 
inhalation,  aromatic  spirits  of  ammonia  for  internal  or  subcutaneous 
use,  also  brandy  or  whiskey  as  stimulants,  together  with  tablets  of 
sulphate  of  strychnine  gr.  ^V  to  -^  for  subcutaneous  use.  For  weak 
and  debilitated  patients,  the  subcutaneous  injection  of  morphine,  gr. 
I  to  \,  and  gr.  ^^jj  to  ^^^  of  atropine,  previous  to  the  inhalation,  is  rec- 
ommended. The  heart  and  respiration  should  be  carefully  examined 
previous  to  the  administration  of  every  general  anesthetic,  as  a  wise 
precautionary  measure.     A  suitable  mouth  prop  or  gag,  for  separating 


THE  EXTRACTION  OF  TEETH.  457 

the  jaws  and  keeping  them  open,  is  a  necessary  adjunct,  especially 
in  the  use  of  nitrous  oxid,  on  account  of  the  rigidity  of  the  muscles. 

All  of  the  instruments  necessary  to  be  used  should  be  within  easy 
reach,  and  in  case  where  a  number  of  teeth  are  to  be  extracted,  the 
number  of  forceps  should  be  limited,  so  that  there  may  be  as  little 
change  of  instruments  as  possible,  and  for  this  reason  the  universal 
forceps  are  to  be  preferred. 

In  the  administration  of  a  general  anesthetic,  the  operator  should 
invariably  insist  on  the  presence  of  a  third  person  in  the  room  on 
account  of  possible  hallucinations  on  the  part  of  the  patient. 

As  soon  as  the  tooth  is  removed  from  the  mouth,  the  head  of  the 
patient  should  be  slightly  inclined,  so  that  the  blood  may  run  into  the 
cuspidor,  and  the  patient  kept  at  rest  until  complete  recovery  takes  place. 

Whether  teeth  should  be  extracted  when  affected  by  pericementitis, 
or  alveolar  abscess,  is  a  mooted  question.  With  the  remedies  now 
employed  for  the  relief  of  the  after-pains  of  extraction,  the  writer  can- 
not see  any  necessity  for  subjecting  a  patient  to  prolonged  suffering 
by  delaying  the  removal  of  the  offending  tooth. 

The  Chapter  on  "The  Treatment  of  Impacted  Lower  Third 
Molars,"  by  Dr.  C.  Edmund  Kells,  in  this  work,  renders  unnecessary 
any  reference  to  the  subject  at  this  time. 


CHAPTER  XXVII. 
THE  TREATMENT  OF  IMPACTED  LOWER  THIRD  MOLARS. 

BY  C.  EDMUND  KELLS,  D.  D.  S. 

The  removal  of  badly  impacted  lower  third  molars  was  undoubtedly 
always  a  serious  operation,  and  admittedly  sometimes  a  dangerous  one 
according  to  some  authors,  until  1903  when  the  writer  presented  to  the 
profession,  through  a  paper  read  before  the  National  Dental  Associa- 
tion, an  entirely  new  technique  by  which  the  work  is  very  greatly  sim- 
plified, and  practically  freed  from  danger  and  all  subsequent  bad 
effects. 

Having  since  that  date  made  some  changes  in  the  technique, 
though  still  adhering  to  the  basic  principles  of  the  original  operation, 
we  will  only  describe  the  technique  used  today. 

By  an  '^impacted  lower  third  molar"  is  meant  one  which  lies  in  a 
more  or  less  horizontal  position,  and  is  firmly  interlocked  between  the 
ramus  of  the  jaw  and  the  second  molar,  and  it  is  to  such  teeth  only  that 
this  operation  applies.  Third  molars  that  are  found  far  removed 
from  the  second  molar  in  the  ramus  or  body  of  the  jaw  should  be  called 
misplaced,  and  not  impacted  teeth,  for  they  are  really  not  impacted  in 
the  strict  meaning  of  that  word.  Their  removal  when  indicated  calls 
for  special  surgical  procedure  which  need  not  here  be  considered. 

As  a  rule,  an  impacted  third  molar  is  not  brought  to  the  operator 
for  attention  until  the  patient  has  been  suffering  for  some  time,  and 
when  presenting,  the  probabilities  are  that  the  mouth  cannot  be  opened 
to  any  extent,  and  yet  that  same  patient  intelligent  though  he  may  be 
will  expect  to  have  the  tooth  "pulled"  at  once  and  painlessly  at  that. 

Did  these  conditions  obtain  upon  any  other  part  of  the  body,  the 
patient  would  undoubtedly  be  put  to  bed,  most  probably  in  a  sanitarium, 
with  all  the  attendant  annoyances  of  trained  nurses,  speciahsts,  etc. 
and  therefore  there  is  no  reason  why  the  dentist  should  not  be  entitled 
to  some  consideration,  and  refuse  to  operate  until  conditions  become 
more  favorable. 

Possibly  in  extreme  cases,  it  might  be  advisable  to  administer  ether 
or  chloroform,  forcibly  open  the  jaws  and  remove  the  tooth,  but  fortu- 
nately for  the  writer,  in  all  his  experience  he  has  never  met  with  such  a 

459 


460        THE    TREATMENT   OF   IMPACTED    LOWER    THIRD   MOLARS. 

case,  and  he  would  fear  that  the  after  effects  of  such  treatment  would  be 
more  harmful  than  if  a  milder  course  had  been  pursued. 

If,  therefore,  a  patient  presents  unable  to  open  the  mouth,  the  writer 
proceeds  with  every  possible  means  for  reducing  the  local  inflammation 
by  the  use  of  poultices,  leeches  and  warm  lotions  within  the  mouth, 
antiphlogistine  outside  of  the  face  and  neck,  supplemented  when  ad- 
visable, by  the  use  of  some  anodyne,  while  the  nourishment  of  the 
patient  must  be  given  careful  consideration. 

Under  this  treatment  the  patient  should  soon  be  free  from  pain, 
and  conditions  should  improve  more  or  less  rapidly  and  as  soon  as  the 
mouth  can  be  opened  sufficiently  wide,  and  not  before,  the  tooth  will 
be  removed. 

Naturally  when  the  patient  can  open  the  mouth  wide  enough  upon 
presentation,  the  operation  is  not  thus  delayed. 


Fig.  312. 

Impacted  lower  third  molars  should  be  divided  into  two  classes: 

1.  Where  the  distal  cusp  only  of  the  third  molar  has  erupted,  and 
is  plainly  visible,  while  the  mesial  cusp  is  firmly  locked  under  the  con- 
vexity of  the  crown  of  the  second  molar  and: 

2.  In  which  no  part  of  the  third  molar  has  erupted,  and  its  pres- 
ence and  position  are  only  discovered  by  the  skiagraph. 

Class  I.  Good  specimens  from  the  writer's  own  practice  of  such 
cases  are  shown  in  Fig.  312. 

It  is  very  evident  from  the  skiagraphs  that  such  molars  cannot  be 
removed  as  found,  by  means  of  an  elevator  or  forceps  without  breaking 
either  the  third  molar  itself,  or  badly  fracturing  the  overlapping  crown 


THE  TREATMENT  OF  IMPACTED  LOWER  THIRD  MOLARS.    46 1 

of  the  second  molar,  and  it  has  been  the  practice  of  the  leading  oral 
surgeons  to  either  extract  the  second  molar,  and  let  the  third  molar 
alone,  or  to  bur  away  the  bone  covering  the  entire  third  molar  or  from 
its  entire  lingual  side,  before  attempting  its  removal,  these  operations 
being  usually  performed  in  hospitals  and  under  the  influence  of  ether 
or  chloroform,  and  entailing  a  very  considerable  loss  of  bone,  tremend- 
ous mutilation  of  both  soft  and  hard  tissues  naturally  necessitating  a 
long  period  of  repair  and  subsequent  treatment. 

It  does  appear  to  the  writer  that  the  removal  of  these  impacted 
molars  can  best  be  undertaken  in  a  dental  ofl&ce,  and  with  a  local 
anesthetic. 

Here  the  patient  is  placed  in  a  sitting  posture,  and  the  best  of  light 
is  secured.  The  saliva  tube  keeps  the  mouth  dry.  The  dental  engine 
and  all  other  necessar}'  accessories  are  only  to  be  found  in  a  well- 
appointed  dental  office.  With  all  these  advantages,  why  should  not 
this  work  be  performed  better,  more  quickly  and  with  less  tax  upon 
both  the  patient  and  operator  than  if  done  in  a  hospital. 

Upon  studying  the  skiagraphs  of  such  cases  in  the  early  days  of 
X-ray  work,  it  occurred  to  the  writer  that  if  the  interlocking  mesial 
cusp  of  the  imprisoned  third  molar  were  cut  away,  it  would  then  be 
released,  and  therefore  but  little 
cutting  away  of  the  surrounding 
process  would  be  necessary  to 
allow  of  its  removal  with  com- 
parative ease,  and   putting   this 
theory  into  practice  proved  its 
correctness. 

In  Fig.  313,  are  seen  the  teeth 
of  cases  shown  in  Fig.  312,  the  mesial  cusps  having  been  cut  away 
before  their  removal. 

That  was  the  original  operation,  now  to-day  instead  of  cutting  off 
the  mesial  cusp  only,  the  mesial  half  or  more  of  the  crown  itself  is  cut 
off  as  will  now  be  described. 

First  a  skiagraph  of  the  tooth  is  taken  upon  a  film  held  within  the 
mouth,  from  which  we  should  learn  at  least  the  general  contour  and 
position  of  the  tooth.  If  for  any  reason  this  skiagraph  cannot  be 
taken,  then  one  should  be  attempted  with  a  plate  held  on  the  side  of 
the  head. 

When  ready  to  operate,  the  mouth  is  first  sprayed  or  rinsed  (or 
both)  with  a  weak  solution  of  hydronaphthol  or  other  antiseptic,  the 
tissues  around  the  molar  and  well  up  on  the  ramus  are   thoroughly 


Fig. 


462         THE   TREATMENT   OF   IMPACTED   LOWER   THIRD   MOLARS. 

sponged  off  with  pyrozone,  sprayed  again,  dried  and  painted  with  iodin, 
thus  rendering  the  field  of  operation  as  aseptic  as  possible. 

1.5  c.c.  Novocain  L.  Suprarenin — Synthetic  2  per  cent  solution  are 
injected  into  the  Pterygo-mandibular  space  in  which  is  found  the  alveo- 
lar nerve,  and  .5  c.c.  of  this  solution  is  injected  into  the  region  half  way 
between  the  point  of  entrance  of  the  needle  and  the  alveolar  nerve,  a 
very  small  quantity  being  injected  at  the  moment  of  the  insertion  of 
the  needle  as  usual.  Thus  anesthesia  of  the  inferior  alveolar  and 
lingual  nerves  is  obtained,  which  allows  of  a  painless  operation. 

The  effects  of  the  Novocain  are  not  exhibited  immediately,  but  in 
from  twenty  to  forty  minutes  entire  sensation  in  and  around  the  molar 
should  have  disappeared,  the  operation  being  commenced  after  the  gum 
has  become  insensible.  At  the  last  moment  ^  c.c.  of  this  solution  should 
be  injected  in  the  gum  on  the  sides  of  the  third  molar.* 

The  gum  above  the  entire  crown  only  is  incised  and  removed.  The 
process  above  the  crown  down  to  the  neck  of  the  tooth  only  is  removed  by 

burs,  usually  about  a  No.  4  round  bur  in 
the  straight  or  contra-angle  hand  piece 
whichever  will  reach  most  advantageously. 
This  bur  is  then  run  down  the  lingual  and 
'  '^^^'  buccal  surfaces  of  the  crown  only,  remov- 

ing the  process  adjacent  thereto. 

Next  with  a  small  diamond  disk  or  knife  edge  carborundum  stone, 
\  in.  to  f  in.  in  diameter,  the  tooth  is  well  nicked  transversely  in 
about  the  center  of  the  crown. 

With  one  of  the  writer's  special  impaction  burs  of  extra  length  (Fig. 
314)  in  the  contra-angle  handpiece,  the  crown  of  the  tooth  is  severed 
perpendicularly  by  a  sawing  motion  of  the  bur,  the  handpiece  being 
meanwhile  tilted  first  to  the  lingual  and  then  to  the  buccal  down  to  an 
angle  of  possibly  forty-five  degrees,  the  bur  cutting  right  down  through 
the  pulp  chamber  painlessly.  In  Fig.  315  are  shown  teeth  which  were 
removed  by  cutting  them  through  in  this  manner.  A  model  of  the  case 
as  presenting  is  first  shown,  then  a  skiagraph,  and  lastly  the  tooth 
which  was  removed  and  placed  in  a  plaster  model  for  reference. 

In  Fig.  316  is  shown  a  tooth  of  which  fully  one-third  was  cut 
off,  and  this  was  done  painlessly. 

Two  of  these  cases  belong  to  Class  II,  as  there  were  no  indications 
of  the  presence  of  the  molars,  and  they  were  only  discovered  by  the 
writer  pursuing  his  usual  practice  of  always  looking  for  past  due  un- 
erupted  third  molars. 

*  For  this  method  of  conductive  anesthesia  credit  must  be  given'Dr.  Guido  Fischer. 


THE   TREATMENT    OF    IMPACTED    LOWER    THIRD    MOLARS.       463 

With  the  enamel  of  this  tooth  as  dense  and  hard  as  it  invariably  is, 
this  is  no  rapid  process  and  several  burs  will  be  used  up  before  the 
crown  is  finally  separated.     By  carefully  following  these  instructions 


Fig.  315. 

very  little  or  no  mutilation  of  the  soft  tissues  occurs — a  very  desirable 
attainment. 

Once  the  crown  is  severed,  the  anterior  portion  then  being  loose 
is  readily  removed  by  almost  any  small  beaked  forceps,  such  as  are 
found  in  every  set  of  extracting  instruments,  or  it  may  easily  be  brought 
to  the  surface  by  any  suitable  elevator. 

With  plenty  of  space  thus  made  for  the  forward  movement  of  the 
root  and  the  process  having  been  removed 
as  previously  described  from  the  sides  of 
the  remaining  portion  of  the  crown  it  is  not 
very  difficult  to  work  the  beaks  of  a  suitable 
pair  of  forceps  down  so  as  to  get  a  good  hold 
upon  the  remaining  portion  of  the  crown  and 
gradually  with  a  twisting  motion  and  a  for- 
ward pull  loosen  the  tooth  from  its  socket. 

However  great  care  must  be  taken  at  this  stage  and  if  the  tooth 
will  not  start  under  moderate  force  it  might  be  advisable  to  bur  away 
more  of  the  surrounding  process,  and  possibly  start  it  from  its  seat  by 
an  elevator.     Finally  the  root  will  yield  when  after  being  drawn  well 


Fig.  .-^jio. 


464 


THE   TREATMENT   OF   IMPACTED   LOWER  THIRD   MOLARS. 


forward  it  can  readily  be  raised  and  removed  from  the  mouth  without 
further  difficulty. 

All  forceps  upon  the  market  as  far  as  the  writer  knows  being  de- 
signed for  the  extraction  of  the  teeth  which  stand  vertically  in  the  jaw 
are  naturally  not  so  well  adapted  to  teeth  in  the  horizontal  position. 

Therefore  their  selection  requires  no  little  care  and  judgment  as 
undoubtedly  no  other  tooth  varies  so  much  from  a  standard  form  as  the 


Fig.  317 


Fig.  319. 


Fig.  320. 


one  in  question.  It  is,  however,  most  fortunate  that  the  portion  of  the 
tooth  to  be  grasped  is  strong  and  solid  and  even  though  the  forceps  do 
not  fit  perfectly  there  is  little  danger  of  breaking  the  root. 

Large  roots  like  those  shown  in  Fig.  313,  could  be  fairly  well  grasped 
by  the  special  forceps  shown  in  Fig.  317.  Those  shown  in  Fig.  318, 
are  No.  45  of  the  Ash  make  but  have  been  ground  out  in  such  a  manner 


THE    TREATMENT    OF    IMPACTED    LOWER    THIRD    MOLARS.        465 

as  to  make  them  grasp  a  horizontal  tooth  very  satisfactorily  in  many 
cases.  Upon  closing  these  beaks  on  the  remaining  portion  of  the 
tooth  the  action  is  Uke  that  of  a  double  inclined  plane  tending  to  force 
the  beaks  downward  and  thus  precluding  their  slipping  off. 

Sometimes  either  of  the  forceps  shown  in  Fig.  319,  and  Fig.  320, 
will  appear  to  fit  and  grasp  the  tooth  to  the  best  advantage.     These  are 


Fig.  321. 


also  special  instruments  made  for  the  writer  in  his  early  days  for  the 
extraction  of  lower  single-rooted  teeth  or  single  roots  of  molars,  at  that 
time  there  being  no  instruments  on  the  market  of  a  similar  design. 
They  have  smooth  beaks  and  operate  upon  the  elevator  principle. 

The  writer's  complement  of  extracting  instruments  would  be  most 
incomplete  did  it  not  include  the  elevators  shown  in  Fig.  321,  which 
were  made  in  his  father's  office  more  than  forty  years  ago.    For  start- 
30 


466         THE   TREATMENT   OF   IMPACTED   LOWER   THIRD    MOLARS. 

ing  from  their  sockets  both  impacted  and  free  lower  third  molars  they 
are  frequently  invaluable. 

Upon  the  removal  of  the  tooth  the  patient  should  hold  a  warm 
antiseptic  solution  in  the  mouth  changing  it  frequently  for  fifteen 
minutes  at  least  when  the  injured  tissues  are  dried,  painted  with  tinc- 
ture of  aconite  and  iodin  (equal  parts)  which  completes  the  operation. 

Never  under  any  circumstances  should  the  socket  he  packed  with 
gauze  or  anything  else  if  the  operatioti  has  been  performed  as  indicated 
for  the  blood  clot  and  saliva  are  the  very  best  remedial  agents  to  be  had. 

The  patient  is  instructed  to  bathe  the  mouth  at  intervals  of  every 
two  or  three  hours  for  three  to  five  minutes  at  a  time  with  a  warm  weak 
solution  of  Pond's  Extract,  Tichenor's  Antiseptic  or  Hydronaphthol 
and  to  return  the  following  day. 

At  this  sitting  the  socket  is  generally  washed  out  with  a  warm  an- 
tiseptic solution.  Sometimes  when  advisable  the  socket  is  dried  and 
touched  with  phenol  and  then  thoroughly  but  gently  swabbed  with 
aconite  and  iodin.  If  not  necessary  the  phenol  is  omitted  and  only 
the  aconite  and  iodin  used. 

This,  treatment  is  repeated  at  intervals  of  two  or  three  days  as  long 
as  necessary,  possibly  a  week  or  ten  days  during  which  length  of  time 
it  is  well  to  keep  an  eye  on  the  condition  of  the  socket. 

By  the  removal  of  an  impacted  molar  in  this  manner  there  occurs 
no  undue  laceration  of  the  soft  parts  nor  any  great  strain  upon  or  frac- 
ture of  the  alveolar  process.  The  conditions  are  the  very  best  for  rapid 
healing  and  as  a  matter  of  fact  rapid  healing  does  take  place.  The 
writer  has  had  some  cases  in  which  he  did  absolutely  nothing  to  the 
socket  after  the  day  of  operation. 

New,  perfectly  sterilized  burs  are  always  used  in  this  work. 

Having  found  it  impossible  to  wash  out  a  deep  socket  satisfactorily 
with  any  syringe  or  spray  available  the  writer  devised  the  following 
appliance  for  this  purpose. 

A  silver  tube  No.  13  B.  &  S.,  and  about  six  inches  long  was  fitted 
with  a  small  ball  at  one  end  and  to  its  center  was  slipped  a  small  piece 
of  rubber  tubing  by  which  the  tube  can  be  held  securely  in  an  Ivory 
porte  polisher  and  therefore  more  easily  manipulated. 

To  the  free  end  of  the  tube  is  attached  two  or  three  feet  of  rubber 
tubing  connected  in  turn  with  an  ordinary  DeVilbiss  bottle  which  throws 
a  fine  stream  instead  of  spray.  In  use  the  ball  end  of  the  tube  is  bent 
so  it  can  reach  the  bottom  of  the  socket  where  it  is  placed  and  which 
from  its  shape  it  will  not  injure.  The  bottle  filled  with  a  warm  antisep- 
tic solution  is  held  by  the  assistant.     It  is  connected  to  the  compressed 


THE    TREATMENT    OF    IMPACTED    LOWER    THIRD    MOLARS.        467 

air  outlet,  the  saliva  tube  is  correctly  adjusted,  and  at  the  given  signal 
the  assistant  opens  the  valve  slightly. 

In  this  manner,  through  the  flexibility  of  the  rubber  connections  the 
operator  can  manipulate  the  silver  tube  with  the  delicacy  of  a  pen. 
Thus  a  gentle  stream  painlessly  and  thoroughly  washes  out  the  entire 
socket,  the  contents  of  the  bottle  being  quickly  run  through  the  mouth. 
In  the  absence  of  compressed  air  the  practitioner  can  improvise  some- 
thing which  will  answer  by  using  a  syringe  in  place  of  the  bottle  and 
connecting  it  to  the  silver  tube  by  rubber  tubing. 


Fig.  322. 


In  Fig.  322,  is  shown  this  appliance. 

The  mere  fact  that  a  lower  third  molar  is  impacted  does  not  neces- 
sarily call  for  its  removal  and  sometimes  a  very  careful  examination 
must  be  made  upon  which  to  base  a  diagnosis. 

In  a  comparatively  young  patient  when  there  is  inflammation  about 
an  impacted  lower  third  molar  we  may  usually  attribute  the  cause 
entirely  to  the  third  molar  itself  and  if  this  proves  to  be  the  case 
extract  it. 

But  later  in  life  especially  when  there  is  no  inflammation  of  the 


468 


THE   TREATMENT    OF    IMPACTED    LOWER   THIRD    MOLARS. 


surrounding  parts  and  the  patient  complains  of  pain  in  that  region  one 
must  be  very  careful  in  his  diagnosis  for  if  the  conditions  are  like  those 


Fig.  323. 


Fig.  324. 


shown  in  Fig.  323,  it  will  be  readily  seen  that  the  removal  of  the  third 
molar  will  not  cure  the  trouble. 


THE    TREATMENT    OF    IMPACTED    LOWER    THIRD    MOLARS. 


469 


A  much  more  marked  case  is  shown  in  Fig.  324,  which  is  only  inserted 
here  as  a  matter  of  interest  as  it  is  an  upper  case. 

Here  we  see  that  the  distal  surfaces  of  the  second  molars  beneath 


■PBVH^^^HHIH 

jj 

1 

Fig.  325. 


Fig.  326. 

their  enamel  lines  have  been  abraded  (not  absorbed)  by  contact  with 
the  impacted  third  molars  to  such  an  extent  as  to  expose  their  pulps. 

When  this  has  progressed  so  far,  as  in  these  cases,  that  the  tooth 
cannot  be  filled  and  saved  then  the  second  molar  should  be  extracted^ 


470         THE   TREATMENT   OF   IMPACTED    LOWER   THIRD    MOLARS. 

when  the  third  molar  will  gradually  erupt  and  possibly  become  a  use- 
ful member  of  the  dental  arch. 

The  writer  has  been  surprised  to  see  the  favorable  positions  taken 
by  such  third  molars  in  the  course  of  from  five  to  ten  years. 

Such  cases  cannot  but  emphasize  the  necessity  for  the  early  skia- 
graphing  of  all  unerupted  and  past  due  third  molars  and  when  neces- 
sary removing  them  before  they  injure  the  second  molars. 


^r                              ^ 

■■ 

^ 

^k 

-<'^ "  ■ 

•jr.',    _^^^^B 

Fig.  327. 

In  Fig.  325  is  seen  a  good  example  of  the  disadvantages  of  delay 
in  removing  an  impacted  lower  third  molar. 

In  1905  this  unerupted  lower  molar  was  discovered  by  means  of  a 
skiagraph  but  the  patient,  a  highly  strung  nervous  young  lady,  would 
not  listen  to  its  removal  because  it  gave  her  no  trouble.  Now  eight 
years  later  she  comes  in  suffering,  and  with  the  third  molar  still  in- 
visible, which  means  that  this  has  burred 
its  way  into  the  second  molar  and  she  will 
undoubtedly  lose  that  tooth. 

Again  in  Fig.  326,  is  shown  a  case  where 
the  third  molar  was  only  discovered  by  the 
X-ray,  found  just  sufficiently  interlocked  to 
prevent  its  eruption  but  not  sufficiently 
mal-posed  to  warrant  its  extraction. 

The  gum  over  it  was  entirely  cut  away. 
Then  for  three  months  the  tooth  was  con- 
stantly worried  first  with  wedges  of  cotton 
forced  under  the  mesial  cusp  and  later  with  silk  and  wooden  wedges 
and  occasionally  using  force  upon  a  thin  bladed  steel  instrument.  At 
the  end  of  this  time  the  tooth  was  released  and  started  upward  where- 
upon operations  were  suspended.  In  due  course  of  time  this  tooth 
will  undoubtedly  fully  erupt  without  further  assistance. 

Model  327  shows  its  condition  one  year  after  the  work  was  begun. 

In   Fig.   328  is  shown    another    such   case   under  treatment  as 

just  described  at  the  present  writing.     The  third  molar  is  securely 


Fig.  328. 


THE    TREATMENT   OF    IMPACTED    LOWER    THIRD    MOLARS.      '47 1 

locked  but  stands  so  near  the  vertical  that  the  writer  is  assured  of  the 
possibility  of  its  forcible  eruption  and  becoming  a  useful  tooth. 

In  Fig.  329,  is  shown  what  is  probably  the  most  remarkable  case 
of  impacted  third  molars  on  record. 

They  are  all  in  the  mouth  of  a  young  woman  and  have  been  watched 
by  the  writer  for  nearly  ten  years;  she  has  never  been  aware,  of  their 
presence  and  it  is  certainly  to  be  hoped  that  she  never  will  be. 


Fig.  329. 

It  is  the  writer's  regular  practice  to  skiagraph  the  region  for  all 
missing  third  molars  in  adults  where  there  are  any  possibilities  of  their 
not  having  been  extracted  and  in  that  way  he  has  undoubtedly  rendered 
many  patients  invaluable  service. 

The  work  herein  described  was  only  rendered  possible  through  the 
agency  of  the  Roentgen  Ray  and  is  but  one  of  many  lines  in  which  den- 
tistry has  been  placed  under  the  greatest  of  obligations  to  Prof.  Roentgen, 
their  discoverer. 


CHAPTER    XXVIII. 
iHE  PLANTING  OF  TEETH. 

BY  C.  EDMUND  KELLS,  JR.,  D.  D.  S. 

The  planting  of  teeth  in  the  human  jaws  may  be  done  under 
various  conditions,  and  therefore  the  operations  may  be  classified, 
chronologically  as  they  were  introduced  into  the  practice  of  dentistry, 
as  follows: 

1.  Replanting-. 

2.  Transplanting. 

3.  Implanting. 

Replanting. — By  this  term  is  designated  the  operation  of  restoring 
to  its  original  socket  the  tooth  which  has  been  torn  therefrom  either 
accidentally  or  intentionally.  This  operation  has  been  more  or  less 
in  vogue  ever  since  the  days  of  Ambrose  Pare,  who  died  in  1590,  and 
today  is  considered  good  practice  by  many  of  our  ablest  operators, 
under  the  following  conditions: 

A.  When  the  tooth  has  been  accidentally  removed  by  force. 

B.  When  a  tooth  has  been  accidentally  removed  by  the  forceps. 

C.  As  a  last  resort  to  cure  a  refractory  alveolar  abscess. 

A.  In  almost  any  case  where  one  or  more  of  the  anterior  teeth 
were  knocked  out,  it  would  be  no  less  than  criminal  neglect  for  the 
operator  not  to  at  least  attempt  their  replacement.  Under  these 
circumstances  the  tooth  should  be  carefully  washed  and  examined. 
If  the  crown  is  found  fractured  or  badly  cracked,  it  should  be  cut  ofif 
and  replaced  by  an  artificial  substitute.  If  carious,  it  should  be  filled. 
Pulp  chamber  and  root  canal  should  be  cleansed  and  filled.  The 
writer  prefers  to  fill  from  the  crown,  using  oxy-chloride  of  zinc  for 
filling  the  pulp  chamber  and  canal,  after  which  the  foramen  is  enlarged 
and  the  canal  drilled  and  tapped,  and  a  gold  screw  inserted,  using 
the  S.  S.  White  "anchor"  screw  instruments  for  the  purpose.  This 
insures  the  substantial  and  perfect  sealing  of  the  end  of  the  canal. 
The  cavity  in  the  crown  is  then  filled  with  whatever  material  is  best 
suited  to  the  case  in  hand,  after  which  the  tooth  is  placed  in  an  anti- 
septic solution. 

As  to  the  best  time  to  replace  the  tooth,  there  appears  to  be  a 

473 


474  THE  PLANTING  OF  TEETH. 

difference  of  opinion.  Some  operators  prefer  to  await  the  subsidence 
of  the  local  inflammation  which  naturally  follows  the  injury,  whilst 
others  insist  that  the  sooner  the  teeth  are  replanted,  the  better. 

However,  whenever  the  tooth  is  replaced,  the  method  of  procedure 
is  about  the  same.  The  entire  mouth  and  socket  should  first  be  sprayed 
with  an  antiseptic  solution,  and  the  region  about  the  socket  protected 
by  napkins.  The  hands  having  been  previously  well  cleansed  by  the 
use  of  carbolic  soap,  the  blood  clot  is  removed  from  the  socket  which 
is  then  carefully  swabbed  out  with  cotton  saturated  with  the  antiseptic 
solution.  The  tooth  is  then  taken  from  its  bath,  a  crystal  of  resorcin 
placed  upon  its  apex  and  then  quickly  inserted  into  the  socket.  If 
by  slow  and  gentle  pressure  the  tooth  cannot  be  returned  to  its  original 
position,  the  writer  believes  it  better  practice  to  enlarge  the  socket 
rather  than  shorten  the  root. 

Just  as  a  surgeon  considers  it  necessary  to  hold  in  firm  apposition 
the  two  ends  of  a  broken  bone,  so  it  is  essential  that  the  replaced 
tooth  should  be  firmly  fixed  in  its  position.  While  wire  or  silk  ligatures 
are  used  by  some,  it  is  undoubtedly  better  to  swage  by  the  usual 
method  a  cap  of  No.  30  pure  gold  to  fit  the  crown  of  the  replaced  tooth 
and  one  or  more  on  each  side,  which,  when  cemented  in  place,  will 
hold  it  firmly  in  position  during  the  process  of  repair — usually  about 
four  weeks.  This  splint  should  not  extend  quite  to  the  gum  line  and 
the  proper  occlusion  of  the  teeth  should  be  carefully  considered. 

The  after  treatment  of  these  cases  consists  in  applying  the  tincture 
of  aconite  and  iodin  (equal  parts)  twice  daily  to  the  dried  gums  about 
the  socket  and  adjoining  teeth  until  all  soreness  disappears.  The 
patient  should  be  instructed  to  thoroughly  cleanse  the  region  about 
the  replanted  tooth  after  each  meal,  which  can  best  be  done  with  an 
antiseptic  solution  in  an  ordinary  rubber  bulb  syringe.  With  this 
the  liquid  can  be  readily  and  forcibly  injected  between  the  teeth  and 
thus  keep  them  free  from  debris. 

The  patient  should  be  kept  under  constant  surveillance  and 
should  the  splint  loosen,  it  should  be  re-cemented  at  once.  At  the 
end  of  the  fourth  week  the  splint  should  be  carefully  removed  and  if 
the  tooth  is  not  found  to  be  perfectly  solid,  replaced  and  worn  until 
perfect  union  has  been  obtained. 

B.  A  tooth  might  be  accidentally  removed  by  the  forceps  by  the 
slipping  of  the  instrument  during  the  operation,  due  to  the  move- 
ment of  the  patient,  or  by  the  operator  in  undue  haste  placing  his 
instrument  upon  the  wrong  tooth. 

Again,  the  crown  of  a  lower  first  molar  having  been  lost,  the 


THE  PLANTING  OF  TEETH.  475 

second  molar  may  have  tipped  forward  to  such  an  extent  that  any 
attempt  to  remove  the  ofttimes  diverging  roots  of  the  first  molar  would 
result  in  dislodging  the  second  bicuspid. 

Such  roots  should  be  separated  by  a  suitable  instrument  in  the 
dental  engine  and  each  root  extracted  separately  which  would  remove 
all  possible  danger  to  the  second  bicuspid. 

The  same  method  of  treatment  previously  described  should  be 
followed  in  cases  of  accidental  extraction,  and  in  such  instances  the 
teeth  always  replaced  without  unnecessary  delay. 

C.  Notwithstanding  the  advanced  methods  of  treatment  of  diseased 
teeth,  by  amputation  of  the  ends  of  the  roots,  removal  of  necrosed 
portions  of  the  alveolar  process,  etc.,  etc.,  there  still  present,  from  time 
to  time,  cases  of  alveolar  abscess  which  cannot  be  cured  by  the  ordinary 
means. 

Usually  these  conditions  are  caused  by  either  the  root  filling  or 
a  broken  instrument  protruding  through  the  end  of  the  root,  or  on  the 
other  hand  from  the  failure  of  the  root  filling  to  reach  the  end  of  the 
canal. 

Under  these  circumstances,  when  all  other  methods  have  failed 
and  as  a  last  resort,  the  operation  of  replanting  is  justified,  and  usually 
results  in  a  cure. 

Here  again  the  operative  procedure  differs  radically  with  different 
operators.  Some  always  cut  off  the  end  of  the  root  and  do  not  replace 
the  tooth  for  some  time,  waiting  for  the  conditions  about  the  socket  to 
improve.  Others  never  alter  the  roots  if  it  can  be  avoided,  and  replant 
at  once.     The  writer  uses  the  latter  method. 

In  extracting  a  tooth  for  the  purpose  of  replanting,  the  utmost 
care  must  be  exercised  in  selecting  forceps  that  fit  the  tooth  and  will 
not  check  or  mar  the  crown. 

Once  it  is  in  hand,  the  cause  of  the  trouble  will  be  seen  and  must 
be  removed.  The  tooth  is  then  treated  as  previously  described. 
The  socket  is  carefully  washed  out,  making  sure  to  include  and  cleanse 
the  pus  pocket  thoroughly,  curetted  if  necessary,  and  the  tooth  replaced 
under  antiseptic  conditions  and  splinted  firmly  in  place.  Under  these 
circumstances  the  splint  should  have  been  made  before  the  tooth  was 
extracted. 

Replanting  for  the  cure  of  pyorrhea  is  practically  impossible. 
The  operation  is  not  warranted  when  the  disease  is  in  its  incipiency, 
at  which  time  the  operation  might  prove  successful  in  eradicating  the 
disease,  and  later  on  when  it  would  be  tolerated,  the  loss  of  the  socket 
enders  it  impracticable. 


476 


THE    PLANTING    OF   TEETH. 


Prognosis. — Usually,  sooner  or  later,  the  roots  of  replanted 
teeth  become  absorbed  and  finally  the  teeth  are  lost.  However,  such 
teeth  have  been  reported  still  in  good  condition  twenty  years  after 
replanting.  The  writer  has  under  observation  a  first  lower  molar 
still  in  good  condition  which  he  replanted  over  fifteen  years  ago. 

Fig.  330  shows  model  and  a  skiagraph  of  this  case  taken  during 
the  preparation  of  this  chapter. 

These  roots  present  a  very  unusual  appearance  for  a  replanted 
tooth.  As  will  be  stated  later  on,  the  pericementum  shows  in  a 
skiagraphic  picture  as  a  white  line  around  a  normal  root.  In  this 
instance  this  white  line  is  present  in  its  entirety,  and  it  assuredly  appears 


n 

1''^^ 

Bfr''-  '^^^^ 

jw^ii 

Fig.  330. 


that  the  pericementum  was  revivified  and  not  obliterated  as  usual, 
which  is  most  remarkable.  This  tooth  was  replanted  in  less  than 
two  hours  after  extraction. 

The  value  of  replanting  is  very  forcibly  shown  by  the  following 
case. 

While  in  the  act  of  brushing  her  teeth  a  lady  fainted  and  fell  to 
the  floor,  the  handle  of  the  brush  driving  the  right  upper  lateral  up 
into  the  maxillary  bone  and  dislocating  the  upper  central  incisors. 

A  skiagraph  of  the  case  was  taken  to  discover  if  possible  the  con- 
dition surrounding  the  roots  of  these  teeth. 

Figure  331  shows  a  model  of  the  case  as  presented  and  in  figure 
332  is  shown  a  skiagraph  showing  the  root  of  the  lateral  fractured 
diagonally. 

The  two  parts  of  this  tooth  were  carefully  extracted,  put  together 
by  an  iridio-platinum  screw  set  in  cement,  and  the  repaired  tooth  then 
replanted.  The  centrals  were  reduced  to  their  proper  positions  and  a 
gold  splint  put  on. 


THE   PLANTING    OF    TEETH. 


477 


At  this  writing,  sixteen  months  from  the  date  of  the  accident,  the 
three  teeth  in  question  are  in  perfect  condition. 

In  figure  ^i,t,  is  shown  a  model  of  the  case  as  it  now  appears  and  in 
figure  334,  the  skiagraph  taken  immediately  after  the  replanting  of  the 
lateral.     Illustrations  are  kindly  loaned  by  the  Items  of  Interest. 


Fig.  331. 


Fig.  332. 


Transplanting  is  the  operation  of  introducing  into  a  fresh  natural 
socket  a  root  either  freshly  extracted  or  not.  This  operation  also 
dates  back  to  the  days  of  Pard,  and  has  always  been  practised  more 
or  less  until  recent  years. 

However,  at  this  date,  we  may  safely  say  it  has  become  obsolete, 
the  necessity  for  it  having  been  overcome  by  present  methods  of  crown 
and  bridge  work,  and  the  more  modern  operation  of  implanting. 

Implanting. — By  this  is  meant  the  drilling  of  a  socket  into  the 
alveolar  process,  and  implanting  therein  a  natural  root. 


Fig.  333. 


Fig.  334. 


In  1885  Dr.  W.  J.  Younger,  of  San  Francisco,  conceived  and  per- 
formed this  operation,  and  it  was  at  once  and  without  much  thought 
adopted  by  very  many  operators. 

It  being  decidedly  the  most  spectacular  operation  ever  devised 
for  clinics,  scores  of  teeth  were  publicly  implanted  within  the  following 
year  or  two,  and  as  most  of  these  operations  were  performed  under 


478  THE  PLANTING  OF  TEETH. 

decidedly  unfavorable  conditions,  failure  was  the  almost  universal 
result.  These  unfortunate  results  proved. so  very  disastrous  that  the 
operation  so  far  as  the  profession  in  general  was  concerned  was  dis- 
continued almost  as  abruptly  as  it  was  adopted. 

Notwithstanding  these  general  results,  here  and  there  a  careful 
operator  appreciated  that  implanting  with  discretion  was  to  a  certain 
extent  a  success,  and  therefore  had  a  field  of  usefulness  decidedly 
its  own. 

At  this  writing,  when  we  know  that  implanted  teeth  have  rendered 
service  from  five  to  fourteen  years,  it  is  not  rational  to  absolutely  con- 
demn the  operation. 

Indications. — When  a  case  presents  with  one  or  several  of  the 
eight  anterior  teeth  missing  in  single  spaces  and  the  alveolar  process 
is  full,  hard  and  healthy,  it  may  be  stated  without  fear  of  contradiction 
that  a  denture  is  the  least  desirable  method  of  their  replacement. 
A  bridge  is  satisfactory  while  it  lasts,  but  in  the  present  stage  of  the 
art,  such  is  by  no  means  permanent  work,  and  when  it  does  fail  it 
leaves  the  patient  in  a  worse  than  his  original  condition,  through  the 
loss  of  the  supporting  roots.  If  therefore  the  patient  is  a  good  healthy 
subject,  implantation  is  certainly  indicated,  and  if  that  fails,  bridging 
may  still  be  resorted  to. 

Again,  cases  present  where  the  temporary  lateral  remains  in  situ 
for  many  years  after  it  should  have  been  succeeded  by  a  permanent 
tooth.  Finally  the  tooth  is  lost  and  a  skiagraph  reveals  the  absence 
of  the  permanent  tooth  in  the  alveolus. 

In  these  cases,  the  alveolar  process  is  full  and  there  is  plenty  of 
space  therein  for  the  making  of  a  socket,  and  if  the  patient  is  in  good 
health,  certainly  it  would  be  better  to  at  least  first  attempt  implantation 
before  mutilating  the  adjoining  tooth  by  bridging. 

Precautions. — The  drilling  of  a  socket  in  the  alveolus  sounds 
like  a  very  heroic  operation,  while  as  a  matter  of  fact  when  compared. 
to  some  others,  such  for  example  as  the  extraction  of  impacted  third 
molars,  it  is  very  simple. 

As  before  stated,  if  the  alveolar  process  is  not  sufficiently  large  to 
contain  the  socket,  it  should  not  be  attempted.  Otherwise  the  only 
precautions  necessary  are  to  sufficiently  comprehend  the  anatomy  of 
the  parts  so  as  to  avoid  entering  the  nasal  fossa  or  the  antrum,  or 
injuring  the  contents  of  the  anterior  palatine  canal  in  the  upper  jaw, 
or  the  inferior  dental  nerve  in  the  lower. 

The  suggestions  for  the  antiseptic  treatment  given  for  replanting 
hold  good  in  implanting. 


THE   PLANTING   OF   TEETH. 


479 


It  has  been  found  that  mature  roots  are  most  desirable  for  implant- 
ing as  they  appear  to  withstand  the  process  of  absorption  more  suc- 
cessfully than  young  teeth,  and  only  small  straight  roots  should  be 
used. 

In  drilling  the  socket,  great  care  must  be  taken  not  to  perforate 
either  the  external  or  internal  alveolar  plate,  which  would  insure 
failure  of  the  operation. 

Procedure. — As  a  natural  tooth  can  rarely  be  found  to  suit  the 
case  in  hand  for  implanting,  any  desirable  root  may  be  used  and 
a  suitable  artificial  crown,  preferably  porcelain,  mounted  thereon 
after  the  canal  has  been  filled.  An  impression  is  first  taken,  and 
in  the  model  made  therefrom,  a  hole  is  drilled  to  represent  the  socket 
to  be  made  in  the  jaw.  In  this  the  root  is  placed  while  the  crown  is 
made.     The  complete  and  absolute  fixation  of  the  implanted  tooth 


Fig.  335. 


being  necessary,  the  writer  considers  that  the  gold  splint  as  recom- 
mended for  replanted  teeth  should  be  used  here  as  well,  and  this  can 
be  made  from  this  model  after  the  crown  is  completed. 

The  root  and  its  finished  crown  mounted  thereon  is  now  carefully 
cleansed  and  placed  in  an  antiseptic  bath. 

There  is  nothing  better  than  a  compressed  air  spray  for  use  in  the 
planting  of  teeth,  but  if  that  is  not  at  hand,  a  good  atomizer  should 
be  used  with  a  sterilizing  bath.  The  mouth  is  thus  sterilized  as  for 
replanting,  the  hands  carefully  cleansed,  and  the  points  of  all  instru- 
ments to  be  used  immersed  in  a  sterilizing  bath. 

Small  pieces  of  sponge,  having  been  previously  boiled,  are  also 
placed  in  the  bath. 

Novocain,  as  preferred,  is  then  injected  so  as  to  thoroughly 
anesthetize  the  territory  to  be  operated  upon,  whereupon  all  is  in 
readiness  for  the  first  step  of  the  operation,  which  is 


480  THE  PLANTING  OF  TEETH. 

The  cutting  of  the  flap,  which  has  been  done  in  three  ways: 
I.  The  ordinary  X  incision  which  leaves  four  small  corners  of  the 
gum  to  be  turned  up. 

2.  The  letter  H  cut  which  gives  the  operator  two  small 
caps  to  take  care  of,  and 

3.   The  ( )  shaped  cut  which  gives  him  but  one. 

These  are  shown  in  Fig.  335,  and  an  instrument  well 
shaped  for  their  execution  in  Fig.  336. 

The  cuts  should  be  clean  and  to  the  bone,  and  with  this 
instrument  the  periosteum  and  gum  are  separated  from  the 
alveolar  process  and  turned  upward. 

'■  If  coarse  bladed  round  burs  are  to  be  used  for  drilling  the 
socket,  the  flaps  of  the  gum  in  the  first  and  second  method 
may  not  be  much  injured,  but  if  the  reamers  are  used  they 
would  undoubtedly  be  badly  cut,  it  being  impossible  to  hold 
them  out  of  their  way. 

Experience  has  proven  that  if  provision  is  made  for  ample 
restoration  of  the  gum  upon  the  labial  surface  of  the  implanted 
tooth,  the  lingual  surface  need  not  be  much  considered.  In 
fact  the  satisfactory  restoration  of  the  gum  tissue  appears  to 
be  about  the  least  of  the  difficulties  of  implanting. 

If,  therefore,  the  reamers  are  used  the  third  cut  should  be 
made,  as  the  f^ap  being  large  and  single  can  be  held  away 
from  the  cutter  by  any  suitable  instrument. 

Drilling  of  the  Socket. — For  this  purpose  the  following 
instruments  are  listed  in  the  dental  catalogues.     (Fig.  337.) 

The  writer  prefers  the  Ottolengui  reamers,  and  proceeds  as 
follows  (Fig.  338) : 

A,  being  the  tooth  to  be  implanted,  three  reamers  are 
selected,  one  of  each  size  of  the  root  at  the  points  marked  B 
C  D.  Setting  the  collar  upon  the  smallest  to  gauge  the  full 
depth  of  the  socket,  the  flap  is  held  away,  the  parts  again 
sprayed  and  the  socket  quickly  drilled  to  this  depth.  The 
gauge  on  the  second  reamer  is  set  to  the  point  D,  and  the  socket 
is  correspondingly  enlarged  to  this  depth.  This  operation  is 
repeated  with  the  third  reamer  to  the  point  C.  We  now 
have  a  socket  which  we  are  assured  is  of  the  required  depth 
'       ■  and  of  the  shape  shown  in  Fig.  339. 

Resuming  our  medium  size  reamer,  and  being  careful  to  main- 
tain our  antiseptic  precautions,  the  steps  of  the  cavity  are  gradually 
trimmed  away,  and  we  find  that  with  few  fittings  of  the  root  (after 


THE  PLANTING  OF  TEETH. 


481 


each  of  which  it  is  returned  to  the  antiseptic  bath),  we  have  expe- 
ditiously accompHshed  the  making  of  a  satisfactory  socket. 

Dr.  Robert  Eugene  Payne,  of  New  York,  has  used  the  following: 
An  old  tooth  brush  handle  is  trimmed  at  one  end  to  as  near  the  shape 
and  size  of  the  root  to  be  implanted  as  is  possible — and  it  is  then 
boiled  in  distilled  water  for  two  hours — after  which  it  is  placed  in  the 
sterilizing  solution.  When  the  socket  is  nearly  finished,  this  "form" 
is  pushed  in  with  considerable  force  and  the  alveolar  process  being 
more  or  less  yielding  is  crowded  away  and  the  root  will  fit  the  socket 
snugly. 


1  i  \ 


The  socket  is  then  well  sprayed,  and  carefully  swabbed  out  with 
prepared  pieces  of  sponge  that  no  debris  be  allowed  to  remain  therein. 
A  few  crystals  of  resorcin  are  placed  upon  the  apex  of  the  root,  when 
it  is  pressed  into  place  and  spHnted  firmly  into  position,  where  it  must 
be  held  from  four  to  ten  weeks,  as  may  be  necessary. 

The  same  after  treatment  as  described  for  replanting  should  be 
followed  here.  Strange  as  it  may  appear,  but  Httle  after  trouble 
need  be  expected. 

Difficulties  to  be  Met. — The  problem  of  holding  the  i^nplanted 
tooth  firmly  in  place  is  often  a  difficult  one.  Likewise  is  it  often 
impossible  to  mount  the  crown  in  such  alignment  upon  the  root  as 
to   have  it  exactly  correct  when  placed  in  position  in  the  jaw,  this 


482 


THE   PLANTING    OF   TEETH, 


Fig.  338.      Fig.  339. 


being  due  to  the  socket  in  the  mouth  not  corresponding  exactly  with 
the  one  made  in  the  plaster  cast. 

To  overcome  these  the  writer  has  fitted  the  coping  and  post  to 
the  root  and  set  it  with  gutta-percha  as  shown  in  Fig.  340,  and  im- 
planted this  only.  A  clasp  band  is  then  fitted  to  the  adjoining  teeth  with 
a  projecting  arm  and  tube,  the  latter  fitting  the  post  exactly.  In  Fig.  341 
is  shown  such  method  as  it  appears  in  the  mouth.  By  this  means  is 
avoided  the  thickness  of  the  gold  splint  upon  the 
occlusal  surfaces  of  the  teeth,  and  the  opportunity 
for  maintaining  aseptic  conditions  about  the  im- 
planted root  is  the  best. 

After  the  root  has  become  firm,  the  post  is 
readily  heated  and  removed,  when  the  porcelain 
crown  can  be  added  and  a  perfectly  satisfactory 
alignment  of  the  same  be  obtained. 

By  means  of  the  Roentgen  Ray  the  condi- 
tions about  the  roots  of  planted  teeth  may  be 
studied  with  great  satisfaction.     In  Fig.  342  at 
A  is  shown  a  skiagraph  of  a  replanted  tooth, 
and  its  normal  neighbors  are   seen  at  B.  B.     The  pericementum  is 
more   or  less   clearly   shown  around   the   latter,  while    it   has  been 
obliterated  about  the  planted  tooth,  the  distinct  outlines  of  its  root 
having  faded  away. 

This  clearly  proves  the  accepted  theory  of  the  attachment  of 
planted  teeth,  which  is  as  follows:  The  root  of  the  planted  tooth 
becomes  attacked  and  absorbed  at  different  points,  which 
places  are  immediately  filled  in  with  a  deposit  of  bone. 
Thus  a  solid  union  is  formed  between  the  cementum  and 
the  socket,  the  pericementum  becoming  obliterated. 

Implanted  teeth  may  be  detected  in  the  mouth  by 
tapping  their  crowns  lightly  with  a  steel  instrument,  the 
resultant  sound  being  very  different  from  that  given  off 
by  a  normal  tooth  the  root  of  which  is  surrounded  by 
pericementum. 

The  duration  of  the  root  evidently  depends  upon  the  relative 
ratio  of  damage  and  repair.  In  some  cases,  the  absorption  proceeds 
exceedingly  slowly,  in  others  much  more  rapidly;  but  the  day  finally 
comes  when  the  attachment  becomes  too  weak  to  support  the  crown 
and  it  is  exfoliated  like  a  temporary  tooth.  In  Fig.  343  is  shown 
the  remains  of  an  implanted  tooth  which  had  stood  in  the  mouth  but 
little  over  a  year. 


Fig.  340. 


THE  PLANTING  OF  TEETH. 


483 


Figure  344  is  a  skiagraph  of  an  implanted  root,  the  crown  from 
which  had  come  off.  This  is  a  splendid  illustration  of  the  causes  at 
work  around  such  roots.  The  lines  surrounding  the  cuspid  and 
central  roots  upon  either  side,  represent  the  pericementum.  This 
is  absent  about  the  implanted  root,  it  having  been  obliterated  by  the 
process  of  anchylosis  which  has  taken  place.  Near  its  apex  can  be 
seen  the  first  stages  of  the  process  of  absorption. 


Ftg,  341. 


In  Fig.  345  is  shown  a  skiagraph  of  a  replanted  tooth  nearing  its 
last  days  of  usefulness.  The  gold  screw  with  which  its  apical  fora- 
men had  been  sealed  is  plainly  shown.  Notwithstanding  the  exten- 
sive absorption,  this  tooth  is  still  quite  solid  and  gives  no  external 
evidence  of  its  early  fate. 

Many  implanted  teeth  have  lasted  from  three  to  six  years,  while 


Fig.  342. 


Fig.  343 


Fig.  344. 


a  few  have  been  reported  from  ten  to  fourteen  years.  The  majority, 
however,  fail  within  two  years  and  some  secure  no  attachment  what- 
ever. 

The  writer  considers  that  implanted  teeth  which  prove  of  service 
for  five  years  should  be  classed  amongst  the  successful  and  satisfactory 
dental  operations. 


484 


THE   PLANTING    OF   TEETH. 


Fig.  345- 


Artificial  Roots. — Immediately  upon  the  discovery  of  the  loss 
of  implanted  teeth  by  absorption  various  operators  experimented 
with  artificial  roots  of  numerous  materials  and  shapes.  Posts,  screws, 
and  cribs  of  silver,  tin,  gold,  platinum,  lead  and  porcelain;  all  these, 
and  probably  others  were  tried  but  all 
proved  failures.  Dr.  R.  E.  Payne  con- 
ceived the  idea  of  drilling  a  perfectly 
circular  socket  and  enlarging  it  at  the 
bottom.  In  this  was  placed  a  closely 
fitting  cylindrical  capsule  which  was 
then  filled  with  soft  rubber  which  upon 
pressure  expanded  the  capsule  and 
rendered  it  solid  at  once.  An  ordinary 
continuous  gum  tooth  was  then  cemented 
in  the  capsule  as  shown  in  Fig.  346. 

But  unfortunately  the  tissues  of  the  jaw  will  not  tolerate  these 
capsules  and  they  remain  in  place  but  a  few  wrecks.  One  might 
suppose  that  if  a  silver  elbow-joint  could  be  successfully  inserted 
in  an  arm  and  made  to  do  good  service,  and 
silver  nails  remain  in  bones  in  which  they  have 
been  driven,  that  a  silver  capsule  carefully  ex- 
panded in  the  jaw  would  also  remain  in  place, 
but  such  does  not  follow,  the  reason  being  that 
the  structure  of  the  long  bones  is  different  from 
that  of  the  alveolar  process. 

In   Fig.  347    is  shown   a  platinum   capsule 
which  was  expanded  in  the  jaw,  by  an  instru- 
mefit  devised  for  the  purpose,  where  it  remained  but  a  few  weeks. 

In  Fig.  348  is  shown  a  skiagraph  of  another  of  the  forms  of  cap- 
sules implanted  by  the  writer,  the  picture  having  been  taken  shortly 
after  the  operation.  This  was  held  in  place  by 
a  clamp  and  tube  for  three  weeks,  when  this 
retaining  appliance  was  removed  and  the  cap- 
sule appeared  perfectly  solid.  However,  about 
six  weeks  later  it  loosened  and  came  out. 

In  1889  Dr.  J.  M.  Edmunds  of  New  York  de- 
vised a  cylindrical  root  made  of  No.  28  gauge  plat- 
inum with  oval  openings  cut  into  its  sides,  made 
exactly  to  the  size  of  a  prepared  trephine.  He  then  trephined  the  hone 
(did  not  bur  it  out  as  did  all  other  operators)  being  careful  to  leave  the 
core  standing,  and  into  this  circular  socket  he  forced  his  cylindrical  root 
which  it  just  fitted. 


Fig.  346.        Fig.  347. 


Fig   348. 


THE  PLANTING  OF  TEETH.  485 

Dr.  Edmunds  expected  that  fresh  bone  would  be  grown  in  the  spaces 
in  his  root  and  so  join  the  core  to  the  outside  bone,  thus  securing  his 
crib  firmly  in  place,  but  this  did  not  happen.  The  root  was  exfoliated 
like  all  other  metallic  roots. 

Recently  this  operation  has  been  "invented"  again,  and  while 
success  is  claimed  for  it,  in  the  absence  of  personal  observation,  which 
has  been  lacking,  the  writer  sees  no  reason  for  it  succeeding  any  better 
now  than  twenty-four  years  ago.  However,  should  a  good  case  pre- 
sent, the  writer  will  plant  such  a  crib  and  test  it  for  himself. 

Sterilizing  Agents. — Mercury  bichloride,  i  to  looo,  forms  a  good 
bath  for  all  purposes  in  connection  with  these  operations.  However, 
natural  crowns  should  not  remain  in  it  indefinitely,  or  they  may  become 
discolored. 

Hydronaphthol  dissolved  in  hot  distilled  water  to  the  point  of 
saturation  and  then  filtered,  forms  an  excellent  spray  for  the  mouth 
as  well  as  a  bath  for  the  instruments  and  roots. 

Conclusions. — Before  writing  this  chapter  a  circular  letter  was 
sent  to  many  prominent  dentists  of  this  and  other  countries.  From 
the  replies  thereto,  the  writer  is  lead  to  the  following  conclusions: 

Replanting  is  practised  by  many  conscientious  operators  of  this 
day. 

Transplanting  is  not  practised  at  all. 

Implanting  is  still  practised  by  some  operators,  who,  like  the 
writer,  believe  that  under  certain  circumstances  it  is  advisable. 


CHAPTER  XXIX. 
PYORRHEA  ALVEOLARIS. 

BY  JOHN  DEANS  PATTERSON,  D.  D.  S. 

The  work  of  writing  upon  the  subject  of  "Pyorrhea  Alveolaris" 
in  a  way  to  enable  the  dental  practitioner  to  more  successfully  cope 
with  that  most  distressing  and  destructive  condition  surrounding 
the  dental  organs  becomes  difficult  only  on  account  of  the  fact  that 
members  of  the  dental  profession  have  so  often  been  led  to  believe 
by  many  of  the  writers  upon  the  subject  that  the  disease  is  the  ex- 
pression of  systemic  conditions,  and  that  until  those  conditions  are 
corrected  the  treatment  is  well-nigh  hopeless. 

The  operator  who  is  a  student  of  disease,  if  he  gives  credence  to 
these  statements  is  also  well  aware  of  the  fact  that  the  diseases  of 
faulty  metabolism,  or  those  resulting  in  faulty  metabolism — which, 
according  to  these  writers,  are  largely  causative  of  the  condition  known 
as  "pyorrhea  alveolaris" — are  diseases  rarely  cured  or  even  greatly 
modified;  and  we  can  then  readily  see  that  logically  the  operator  hesi- 
tates to  undertake  a  task  which  promises  so  little  success  to  the 
operator  or  benefit  to  the  patient. 

At  the  outset  of  this  brief  consideration  of  the  subject  the  author 
desires  to  state,  with  a  confidence  based  upon  observation  and  expe- 
rience for  over  twenty-five  years,  that  the  condition  or  disease  commonly 
known  as  "pyorrhea  alveolaris"  is  amenable  to  treatment,  effecting  a 
cure  as  readily  and  satisfactorily  as  the  other  lesions  of  the  dental  organs, 
whether  the  systemic  conditions  which  affect  the  progress  of  the  disease 
are  present  or  absent.  The  writer  is  not  alone  in  this  belief,  as  many 
careful  observers  and  practitioners  have  proved  in  their  clinical  ex- 
perience the  correctness  of  the  statement. 

No  sane  member  of  the  dental  profession  can  rely  upon  cure  in 
every  dental  pathological  condition  with  an  absolute  precision  nor 
can  he  promise  that  when  a  cure  is  brought  about  it  will  be  permanent, 
for  always  a  disease  will  again  be  reproduced  when  like  conditions  en- 
viron which  produced  the  original  lesion;  but  the  chances  for  relief 
to  the  sufferer  are  as  promising  and  as  positive  in  pyorrhea  alveolaris 
as  the  relief  and  cure  following  the  process  of  filling  a  majority  of  ca- 
rious teeth. 

487 


488  PYORRHEA   ALVEOLARIS. 

The  prime  object  of  this  writing  is  to  disabuse  the  mind  of  the 
student  and  practitioner  of  a  belief  in  the  incurabiHty  of  the  condition  in 
question,  and  to  teach  that  he  should  avail  himself  of  all  the  ways  and 
means  to  do  this  work,  just  as  he  docs  for  the  best  methods  of  filling, 
crown-  and  bridge-work,  inlay-work,  or  any  other  of  the  usual  operative 
procedures,  or  he  will  not  do  his  duty  to  suffering  human  beings. 

GENERAL  REMARKS  UPON  THE  NATURE  OF  PYORRHEA 
ALVEOLARIS;  ITS  ETIOLOGY  AND  PATHOLOGY. 

Upon  the  best  of  authority  it  may  be  stated  that  the  susceptibility  of 
tissues  to  the  attack  of  irritants  of  whatever  nature  varies  greatly  in 
dififerent  individuals;  and  that  tissue  character  is  largely  of  heredity. 
This  is  markedly  observed  in  the  oral  mucous  membrane.  It  is  well 
known  that  a  slight  irritant  in  a  given  case  produces  distressing  in- 
flammation, and  that  in  another  case  with  the  same  amount  of  irritation 
the  mucous  membrane  is  scarcely  prejudiced.  A  small  point  of 
calcic  deposit  which  encroaches  upon  the  gingival  border  at  the  cervix 
of  a  tooth  will  in  one  case  produce  pain  and  inflammation,  and  in 
another,  larger  amounts  of  calculus  are  not  appreciable  to  the  pa- 
tient. 

In  a  late  edition  of  Stengel's  work  upon  "Pathology"  this  pre- 
disposition of  tissue  to  irritation  is  commented  upon  as  follows: 

"The  normal  system  is  able  to  cope  with  the  determining  causes 
of  disease  to  a  certain  point  by  its  general  vitality  and  regulative  func- 
tions." "The  degree  of  resistance  to  irritation  differs  in  different  in- 
dividuals in  different  races,  or  with  people  living  in  varying  climatic 
conditions.  In  some  the  degree  of  resistance  may  be  so  great  that 
certain  diseases  are  never  contracted.  In  other  persons  there  is  a 
recognizable  weakness  of  resistance  in  one  direction  or  another,  which 
constitutes  a  definite  predisposition.  The  latter  may  be  either  heredi- 
tary or  acquired.  By  hereditary  predisposition  is  designated  abnor- 
mal weakness  of  resistance  transmitted  from  father  or  mother  to  off- 
spring. They  predispose  to  a  number  of  allied  affections.  This  is 
striking  in  the  case  of  neuropathic  heredity,  in  which  various  forms 
of  nervous  disease  may  appear  alternately  or  irregularly  in  members  of 
a  family.  In  the  occurrence  of  hemophilia  we  have  another  notable 
example." 

The  disease  under  consideration  is  observed  by  all  careful  clinicians 
to  often  affect  each  member  of  a  family  an^d  their  offspring,  and  the 
explanation  must  be  found  in  the  character  of  tissue  which  exhibits  a 
weakness  of  resistance  and  which  is  handed  down  from  one  generation 


REMARKS    UPON    THE    NATURE    OF    PYORRHEA    ALVEOLARIS.      489 

to  another.  It  cannot  be  held,  however,  that  this  difference  is  always 
due  to  heredity,  although  it  may  be  safely  said  this  is  generally  true; 
for  the  tissue  is  brought  to  a  weak  condition  at  times,  which  has  been 
acquired.  General  debility  from  ill  health  and  a  starved  condition  of  tis- 
sues from  lack  of  nutritive  supply  frequently  prejudice  to  the  attack  of 
irritants.  It  is  quite  doubtful,  however,  that  the  acquired  predisposing 
conditions,  which  require  usually  a  long  period  for  the  establishment 
of  prejudiced  tissue,  is  more  than  a  minor  factor  in  the  causation  of 
pyorrhea. 

The  mucous  surfaces  are  ever  under  suspicion  of  certain  char- 
acteristic inflammations  and  ulcerations,  but  it  can  scarcely  be  said 
that  diseases  like  pyorrhea  alveolaris  have  their  inception  without  local 
irritation,  whatever  the  predisposing  factors  may  be. 

For  nearly  half  a  century  the  most  advanced  pathologists  have 
granted  that  even  tumors  no  doubt  have  a  local  cause.  Whatever 
the  predisposition  found  in  heredity  or  environment,  yet  without  local 
irritation  of  some  description  the  proHferation  of  cells  found  in  hy- 
pertrophy does  not  ensue.  If  investigators  in  pathology  tell  us  this, 
well  may  we  put  at  once  aside  the  claim  often  made,  that  the  condition 
under  consideration  is  per  se  of  constitutional  origin  or  caused  by  a 
specific  micro-organism.  Those  who  seek  for  the  etiology  of  pyorrhea 
in  obscure  forces  should  return  to  the  plain  and  provable  logic  of  cause 
and  effect,  and  forsake  the  speculative  and  unreliable.  In  the  etiology 
of  the  condition  the  following  statement  may  be  safely  made:  Any 
irritant,  0}  whatever  nature,  which  impairs  the  integrity  and  continuity 
0}  the  gingival  gum  margin,  may  cause  pyorrhea;  and  without  this 
impairment  the  condition  will  not  be  established.  This  may  be  followed 
by  another  proposition;  viz.,  Systemic  conditions  or  a  constitutional 
diathesis  without  local  irritation  do  not  destroy  the  integrity  of  the 
gingival  border. 

The  irritation  which  may  dissolve  the  integrity  of  the  gingival 
border  may  be  presented  in  various  forms.  The  deposition  of  the 
calcareous  salts  from  the  saliva  upon  the  necks  of  the  teeth  is  the  usual 
form  of  irritation;  next  in  importance  may  be  classed  the  nests  of  putre- 
faction and  fermentation  about  the  gingival  border  and  interproximal 
spaces;  again,  mouth-breathing  dries  the  delicate  border,  and  thus 
function  is  interfered  with;  and  in  all  these  irritations  we  have  the  pro- 
tective reaction  of  inflammation  against  a  common  enemy — irritation. 
Other  irritations  may  also  be  mentioned,  and  include  most  prominently, 
banded  crowns,  careless  use  of  ligatures,  the  use  of  wedges,  the  presence  of 
cavities  holding  food  matter  and  which  is  wedged  in  the  process  of  masti- 


49°  PYORRHEA   ALVEOLARIS. 

cation  into  the  interproximal  spaces;  also  careless  operative  procedures. 
It  is  the  firm  opinion  of  the  writer,  however,  that  calcic  deposits  from 
the  salivary  secretions  combined  with  food  detritus,  the  nests  of  fermen- 
tation and  putrefaction,  the  changes  caused  in  the  mucous  membranes 
by  mouth-breathing,  the  unnatural  cervical  tooth  surface  formed  by 
banded  crowns,  and  proximal  decay,  must  be  considered  the  primal 
and  usual  causes  of  interference  with  and  destruction  of  the  relation 
of  the  gingival  margin  of  the  gum  with  the  cervix  of  the  tooth.  The 
lesion  of  the  gingival  border  is  a  result  of  continued  {generally  long-con- 
tinued and  persistent)  irritation,  such  as  is  found  under  conditions  above 
stated;  and  the  factor  of  causation  found  in  wedging,  ligaturing,  and 
other  temporary  interference  with  the  gingival  border  consequent  on 
operative  procedures,  can  scarcely  be  cited  as  active  causes  for  the  es- 
tablishment of  pyorrhea  alveolaris.  In  summing  up  the  positive  and 
possible  causative  factors  in  producing  this  disease,  the  writer's  close 
observation  of  hundreds  of  cases  confirms  the  statement  that  less  than 
five  per  cent  have  other  origin  than  that  found  in  irritation  from  calcic 
deposits  from  the  mouth-fluids  combined  with  decomposing  food  re- 
mains. 

When  the  first  stages  of  the  disease  are  established  by  a  solution  of 
the  integrity  of  the  gingival  border  from  any  one  of  the  causes  stated, 
the  disease  will  progress,  slowly  or  with  rapid  steps,  until  the  tooth  is 
eventually  lost.  The  rapidity  of  the  course  of  the  disease  will  depend 
upon  the  amount  of  local  irritation  and  the  predisposition  present ;  but 
without  hygienic  care,  remedial  measures,  or  surgical  interference,  it 
remains  in  the  majority  of  cases  but  a  question  of  time  when  the  tooth 
investment  will  be  entirely  lost  and  the  affected  organ  exfoliated. 

Let  us  now  trace  more  minutely  the  pathology  involved  from  the 
first  untoward  symptoms. 

With  the  initial  lesion  and  the  inflammation  of  the  gingival  border 
there  is  at  once  established  the  condition  found  in  all  inflamed  territory 
— viz.,  the  exudation  of  the  contents  of  the  nutritive  vessels,  which 
with  the  presence  of  micro-organisms  eventually  introduces  the  breaking 
up  of  the  exuded  vessel  contents  and  the  adjacent  tissue  into  pus. 
There  rarely  is  found  an  exudation  which  does  not  soon  exhibit  sup- 
purative processes.  This  condition  in  which  exudates  and  pus  are 
exhibited  gives  rise  to  the  precipitation  of  the  calcic  matter  which  is 
invariably  present  in  all  exudations,  and  is  deposited  wherever  a  con- 
venient bursa  for  its  reception  is  afforded.  The  explanation  of  the 
source  of  the  serumal  or  sanguinary  points  and  plaques  found  in  py- 
orrhea is  the  simple  and  reasonable  one,  that  in  all  inflammatory  con- 


REMARKS    UPON   THE    NATURE    OF   PYORRHEA   ALVEOLARIS.     49 1 

ditions  there  are  exudations,  and  whether  they  are  simple  serum,  as  in 
the  first  stages,  or  pus,  as  in  the  later  suppurative  stages,  there  is  in 
this  matter  calcium  phosphate,  calcium  carbonate  and  magnesium 
phosphate,  and  in  the  changed  environment  caused  by  functional  dis- 
turbance these  salts  are  logically  precipitated,  and  thus  form  an  irritant 
to  the  tissue  about  which  it  is  deposited,  inciting  by  its  impact  or  touch, 
inflammation  of  soft  tissue  and  absorption  of  bony  tissue  until  the  tooth 
organ  is  exfoliated.  In  the  opinion  of  the  writer,  the  serumal  deposits 
in  pyorrhea  are  subsequent  to  the  initial  inflammation,  and  are 
directly  from  the  inflammatory  products. 

In  1889,  in  a  paper  read  before  the  joint  meeting  of  the  Ameri- 
can and  Southern  Dental  Associations  at  Louisville,  Kentucky,  the 
writer  made  the  claim  as  stated  above,  and  in  substantiation  spoke 
as  follows  (p.  172-173,  Transactions  of  the  American  Dental  Asso- 
ciation, published  1889): 

"Now,  as  a  matter  of  fact,  all  prominent  pathologists  agree  that 
accretions  of  calcic  matter  may  make  their  appearance  as  a  deposit 
from  purulent  matter  from  inflamed  territory  in  any  part  of  the  human 
body.  Upon  this  subject  I  desire  to  quote  from  the  Hand  Book  of 
Medical  Sciences,  Vol.  I,  p.  743,  as  follows:  'Calcification  consists  in 
the  abnormal  deposit  of  earthy  matter  in  or  around  the  elements  of  a 
tissue,  or  in  the  morbid  product  of  a  pre-existing  inflammatory  process.^ 
The  circulation  of  the  blood  may  be  retarded  and  thus  favor  the  pre- 
cipitation of  the  calcareous  matter  which  it  normally  holds  in  solution.' 
'  Calcification  rarely,  if  ever,  depends  solely  upon  general  causes. 
There  is  always  a  local  influence — very  often  it  is  due  to  a  pre-existing 
inflammation.  Old  accumulations  of  pus,  extravasations  and  exuda- 
tions are  exceedingly  prone  to  calcification.*  'The  simplest  mode  of 
explanation  is  as  follows:  A  certain  amount  of  calcareous  matter  is  a 
normal  constituent  of  the  blood,  in  which  it  is  held  in  solution  by  the 
carbonic  acid  always  present  in  sufficient  quantity  to  keep  in  solution 
twice  the  normal  amount  of  earthy  matter.  When  the  circulation  is 
impeded,  the  carbonic  acid,  because  of  its  great  diffusibility,  is  readily 
absorbed  by  the  tissues,  or  goes  to  form  new  compounds,  necessitat- 
ing a  precipitation  of  the  calcareous  matter.  This  is  likely  to  occur 
in  all  tissues  of  the  body.'" 

After  quoting  the  foregoing  high  authority,  the  writer  said :  "  With 
these  facts  before  us,  does  the  presence  of  calcic  deposits  in  the  pockets 
of  pyorrhea  alveolaris  still  surprise  us,  and  must  we  yet  indulge  in  vague 
surmises  over  its  origin?"  What  I  said  at  that  time  is  a  firm  convic- 
tion today.     These  deposits  are  from  purulent  matter  and  are  the  con- 


492  PYORRHEA    ALVEOLARIS. 

sequence  of  irritation  and  inflammation  from  the  various  local  causes 
referred  to.  They  are  not  precedent  to  a  lesion,  but  invariably  are 
subsequent  to  irritation  and  exudation. 

The  inflammatory  process  established  with  the  precipitation  of 
serumal  calculus  from  inflammatory  products,  the  continuation  of 
the  disease  goes  on  to  the  breaking  down  of  tissue  as  before  mentioned, 
from  the  impact  or  touch — the  mechanical  irritation;  and  this  force  is 
supplemented  by  the  presence  of  pyogenic  bacteria,  which  in  their 
life  processes  cause  toxins,  purulency,  suppuration,  which  by  gravi- 
tation and  capillary  attraction,  infect  and  destroy  the  tooth  invest- 
ment. Soon  there  is  noticed  at  certain  points  pockets  of  increased 
depth,  and  they  indicate  their  presence  upon  the  gum  by  a  reddish  or 
purple  line.  Now  the  tooth  often  commences  to  change  its  position. 
It  elongates,  protrudes,  or  rotates — drawn  by  the  remaining  normal 
attachments,  or  by  the  protective  reaction  of  tissues  which  seek  to 
rid  the  economy  of  a  diseased  member.  This  looseness,  and  the  con- 
sequent malocclusion,  is  also  an  irritant  factor.  These  conditions  soon 
cause  a  profuse  formation  of  pus,  which  exudes  about  the  teeth,  and  in 
deep  constricted  pockets  the  pus  at  times  finds  its  way  through  the  tissue 
at  the  lower  point  of  the  pocket  and  the  abscessed  condition  points  as  in 
ordinary  alveolar  abscess. 

When  the  disease  reaches  the  apical  territory,  the  nutritive  ves- 
sels to  the  pulp  frequently  are  deprived  of  their  function,  and  the  pulp 
takes  on  a  pathological  condition  which  results  in  its  death;  and  so  is 
added  the  additional  irritation  of  common  alveolar  abscess.  If  the 
condition  of  pyorrhea  is  of  long  continuance,  the  root  of  the  tooth  in 
some  cases  is  found  to  be  attacked  and  absorbed  in  spots  at  the  focus 
of  inflammation.  This  has  been  noticed  without  the  complication  of 
the  death  of  the  pulp,  though  more  frequently  when  the  disorganized 
pulp  tissue  assists  in  the  irritation.  The  giant  cells  often  present  in 
continued  inflammatory  territory  in  their  strenuous  attempt  to  protect 
tissues  are  found  to  destroy  them.  In  pyorrhea  the  root  of  the  tooth 
is  occasionally  observed  indented  in  this  manner  immediately  beyond 
the  subgingival  territory. 

The  above  related  conditions  continuing  unalleviated,  the  entire 
attachment  of  the  tooth  becomes  diseased  and  obliterated  and  the 
organ  is  exfoliated. 

In  this  brief  description  of  the  etiology  and  pathology  of  pyorrhea 
the  writer  has  made  no  attempt  to  differentiate  the  various  aspects 
found  in  the  condition  which  are  noticed,  and  which,  in  his  opinion, 
need  not  be  classed  as  distinct  conditions  simply  because  the  degree  of 


DIAGNOSIS.  493 

irritation  and  the  degree  of  predisposition  are  different  in  the  different 
cases  and  produce  various  degrees  of  destructiveness.  A  "true  pyor- 
rhea" and  one  that  is  not  true  is  a  distinction  to  the  writer  not  warranted. 
Because  in  one  patient  the  predisposition  of  poorly  nourished  tissue  is 
present  and  an  apparent  (  !  )  absence  of  local  irritation,  there  is  no 
reason  why  the  condition  should  receive  some  specific  name,  when  com- 
pared to  a  perfectly  normal  patient  whose  teeth  are  exfoliated  by  a 
disease  whose  pathology  is  similar.  There  can  be  no  objection  to 
denominating  pyorrhea  alveolaris  "simple"  or  "complex,"  and  when 
that  is  done,  let  us  be  content  to  observe  its  various  phases  exhibited 
when  observed  in  patients  who  have  various  diatheses  influencing 
its  rapidity  or  destructiveness;  but  let  us  eliminate  a  so-called  dis- 
tinctive nomenclature  for  the  various  phases  of  this  disease,  unless 
it  demonstrates  a  better  scientific  title  to  such  distinction  than  is  as  yet 
made  plain, 

THE  TREATMENT. 

Referring  to  the  etiology  of  caries  of  the  teeth,  the  late  Dr.  W.  H. 
Atkinson  once  said  to  the  writer:  "We  all  have  our  differences  of 
opinion  as  to  the  cause  of  tooth  decay,  but  one  thing  remains  true: 
that  if  we  absolutely  knew  the  cause,  it  isn't  likely  we  could  fill  teeth 
a  bit  better."  This  leads  me  to  remark  that  it  is  very  fortunate  that 
while  writers  and  speakers  seem  far  apart  upon  the  etiology  of  pyorrhea 
alveolaris,  there  is  a  great  unanimity  of  opinion  as  to  the  treatment. 
Upon  this  we  are  upon  comparatively  safe  ground,  and  upon  consulting 
all,  we  find  that  whether  the  disease  is  considered  systemic  or  local, 
hereditary  or  acquired,  from  degeneracy  or  faulty  metabolism,  syphilis 
or  scrofula,  catarrh  or  calomel,  mouth-breathing  or  micro-organisms, 
ligatures  or  lithemia,  indolence  or  insanity,  wedges  or  whisky — the 
treatment  is  the  same.  Those  who  name  the  condition  "interstitial 
gingivitis,"  "alveolar  ulitis,"  "phagedenic  pericementitis,"  "calcic 
pericementitis,"  "pyalogenic  pericementitis,"  "hematogenic  peri- 
cementitis," "infectious  alveolitis,"  " odontolithus, "  etc.,  etc.,  agree 
almost  literally  in  treatment  with  those  who  call  the  conditon  "Riggs' 
disease,"  or  "pyorrhea  alveolaris."  There  is  a  growing  conviction 
among  all  that  with  the  removal  of  all  irritating  and  infectious 
matter  from  and  about  the  teeth,  and  the  maintenance  of  a  vigorous 
oral  asepsis,  pyorrhea  alveolaris,  if  not  too  far  advanced,  is  curable. 

DIAGNOSIS. 

To  the  inexperienced,  rules  by  which  a  correct  diagnosis  may  be 
reached,  thus  framing  a  ground  for  remedial  treatment  which  will 


494  PYORRHEA   ALVEOLARIS. 

promise  a  cure,  are  well-nigh  impossible;  but  it  can  be  safely  stated 
that  if  a  tooth  has  lost  three-fourths  of  its  normal  attachment,  or  ex- 
hibits a  looseness  indicating  that  nothing  remains  save  a  fibrous  or 
ligamentous  attachment,  the  loss  of  the  tooth  is  usually  inevitable  and 
extraction  is  advised.  It  has  been  proved,  however,  that  where  it  is 
practicable  to  place  a  permanent  retainer  upon  such  tooth  or  teeth, 
attaching  them  to  those  comparatively  firm,  freeing  them  from  depos- 
its, sometimes  changing  their  position  in  order  to  stimulate  repair  of 
investment,  and  maintaining  scrupulous  hygienic  conditions,  even 
these  ordinarily  hopeless  cases  are  given  long  life,  and  the  patient  is 
freed  from  the  necessity  of  bridge  work  or  plates.  This  must,  how- 
ever, be  said:  that  the  loss  of  teeth  is  far  better  than  the  continuance 
of  those  in  the  economy  from  which  a  pathological  condition  producing 
infection  of  good  tissue  cannot  be  divorced.  Too  many  practitioners 
in  the  treatment  of  the  dental  organs,  whether  for  pyorrhea  or  other 
morbid  conditions  of  tooth  roots,  lay  too  great  stress  upon  the  evils 
resulting  from  a  broken  denture  from  extraction;  even  if  substitution 
is  possible,  they  subject  patients  to  discomfort  and  infection,  often 
to  an  alarming  extent,  because  of  their  horror  of  sacrificing  a  tooth, 
pretending  to  argue  that  mastication,  digestion,  and  nutrition  are 
thereby  so  interfered  with  that  they  choose  the  lesser  of  two  evils.  It 
must  be  patent  to  those  of  experience  and  observation  that  more  than 
one-half  of  the  human  family  manage  very  cleverly  to  exist,  and  in  robust 
health,  with  a  very  limited  masticatory  apparatus.  With  a  few  bicuspids 
and  molars  more  time  is  required  for  sufficient  mastication  than  if  the 
full  complement  of  teeth  is  present;  but  it  is  nevertheless  true  that 
with  care,  a  very  few  pounds  pressure,  and  more  time,  the  ordinary 
foods  can  be  most  properly  prepared  for  deglutition.  It  is  very  com- 
fortable to  have  teeth  like  a  rhinoceros  to  champ  and  gnash  with  a 
pressure  of  hundreds  of  pounds;  but  the  average  chizen  is  not  a  dock- 
hand  who  must  consume  his  meals  in  a  few  minutes,  and  if  his  choice 
grinders  cannot  be  made  comfortable  or  sanitary  by  the  best  skill,  then 
let  them  be  as  "the  eye  that  offends." 

When  the  diagnosis  is  completed  and  the  hopeless  teeth  and  roots 
are  out  of  the  way,  the  next  step  is  the  eradication  of  disease  causes  and 
disease  results  by  surgical  procedure;  the  all-important  step,  without 
which  no  amount  of  systemic  treatment  or  no  amount  of  local  therapeu- 
tics will  avail  to  cure  or  much  alleviate  the  condition. 

Preparatory  to  establishing  the  surgical  work  the  operator  should 
first  obtain  a  complete  history  of  each  case.  First  as  to  heredity;  find 
if  there  is  a  history  in  progenitors  of  loose  teeth  and  loss  of  teeth  with- 


DIAGNOSIS.  495 

out  caries;  find  how  long  the  condition  has  existed,  the  character  of  the 
discomfort,  whether  there  has  been  annoyance  from  bleeding  gums, 
swelling,  or  a  foul  taste  or  odor.  Enquire  as  to  possible  acquired  pre- 
disposition and  as  to  what  remedial  measures  or  operative  procedures 
have  previously  been  instituted.  Examine  carefully  with  dehcate 
explorers,  mouth-mirror,  and  electric  mouth-lamp  all  affected  sur- 
faces as  to  depth  of  the  disease  galleries  and  as  to  looseness  of  the 
teeth. 

At  this  point  the  next  question  is  to  determine  if  the  pulps  should 
be  removed  from  any  of  the  affected  teeth  upon  which  operations  are 
to  be  performed.  Some  years  ago  it  was  quite  a  popular  belief  that 
these  affected  teeth  were  in  better  condition  for  future  usefulness 
minus  the  pulps.  It  was  argued  that  after  pulp  removal  the  nutritive 
supply  formerly  going  to  the  pulp  was  switched  to  the  pericementum; 
so  thousands  of  pulps  were  sacrificed  needlessly  and  harmfully.  Care- 
ful observers  afterward  came  to  the  conclusion  that  in  the  treatment  of 
pyorrhea  a  more  rapid  and  more  perfect  cure  was  brought  about  when 
the  pulp  remained,  and  that  the  assertion  of  more  nutrition  and  strength 
to  the  tooth's  investment  when  pulp  removal  was  practised  was  with- 
out scientific  basis.  It  is,  however,  true  that  there  are  two  situations  in 
which  the  pulp  should  be  obliterated  before  further  operative  proced- 
ures are  instituted:  first,  in  case  the  diagnosis  convinces  that  the  pulp  is 
in  a  pathological  condition;  and  second,  to  afford  anchorage  for  a  per- 
manently adjusted  splint  for  retention.  If  in  the  progress  of  the  disease 
the  solution  of  the  integrity  of  tissue  at  the  apical  territory  has  been 
accomplished,  it  may  safely  be  said  that  the  pulp  is  probably  affected,  its 
usefulness  past,  and  it  should  at  once  be  removed.  Again,  the  irritation 
causing  the  pulp  to  be  in  a  state  of  chronic  irritation  may  be  occasioned 
by  the  exposed  condition  at  the  cervix  of  the  tooth  or  below  it,  on 
account  of  gum  recession  introducing  thermal  shocks.  If  this  condi- 
tion is  present,  the  pulp  should  also  be  removed.  In  the  second  class  of 
cases,  the  removal  of  the  pulp  in  order  to  properly  adjust  an  appliance 
to  retain  loose  teeth,  the  operation  should  be,  as  in  the  former  case, 
prior  to  the  scaling  operation,  as  upon  the  surface  of  the  root  from 
which  the  pulp  has  been  removed  the  operation  of  scaling  for  obvious 
reasons  is  less  painful. 

There  is  yet  another  operation  which  frequently  may  be  prop- 
erly performed  before  proceeding  further,  and  that  is  the  making  and 
cementing  to  place  the  retainer  to  be  worn.  This  will  guard  against 
starting  the  tooth  from  its  socket  in  forcing  deposits  away,  and  also 
prevent  movement  of  the  root  causing  pain. 


496  PYORRHEA   ALVEOLARIS. 

RETAINERS. 

The  operator's  ingenuity  will  show  him  which  of  the  great  num- 
ber of  retaining  appliances  will  serve  best  in  a  particular  case.  Many 
of  the  splints  or  retainers  used  in  orthodontia  serve  admirably.  The 
purpose  of  the  splint  or  retainer  is  to  prevent  discomfort  from  move- 
ment, to  obtain  complete  surgical  rest,  without  which  the  formation 
of  repair  tissue  is  prevented. 

Now  commences  the  preparation  of  the  mouth  by  the  removal 
of  all  micro-organisms  and  fermentative  or  putrefactive  matter  by 
irrigation.  First  this  should  be  done  by  the  patient  with  warm  water, 
followed  by  water  at  an  increased  temperature,  up  to  140°  F.  This 
should  be  followed  by  Dobell's  solution,  which  is  superior  in  removing 
remaining  viscid  fluids  found  in  the  mouth.  Now  the  operator  will 
follow  with  vigorous  use  of  the  syringe  of  strong  force  with 
blunt  point,  and  following  with  a  slim  point  which  will  enter  the 
deep  pockets  and  flush  out  all  inflammatory  products  which  are  mov- 
able. After  all  possible  poisonous  micro-organisms  and  infectious 
detritus  have  been  removed,  the  next  step  is  to  obtund  the  tissues  to  be 
operated  upon,  so  that  the  operation  may  be  rendered  as  painless  as 
may  be  possible.     The  injection  of  the  tissue  is  not  advised. 

OBTUNDENTS. 

For  the  purpose  of  obtunding,  many  preparations  have  been  ad- 
vocated and  many  methods  advised.  It  is  not  our  purpose  to  canvass 
all  of  them,  on  account  of  necessary  brevity,  but  only  to  advise,  after 
repeated  trial,  what  seems  most  effective  for  the  purpose.  When  the 
field  of  operation  has  been  selected,  dry  the  parts  and  pockets  and 
saturate  with  the  following  mixture,  for  which  we  are  indebted  to  Dr. 
Cravens,  of  Indianapolis: 

"Put  half  an  ounce  of  chloroform  in  a  suitable  bottle,  add  freshly 
pulverized  hydrochlorate  of  cocain,  shaking  and  waiting  a  few  seconds 
after  each  addition  of  the  akaloid  until  the  solution  clears.  To  this 
add  six  to  eight  drops  each  of  oil  of  cloves,  cassia,  and  menthol,  and 
add  to  all  a  flavoring  extract  to  render  agreeable." 

This  mixture  seems  greatly  more  effective  in  obtunding  the  tissue 
than  all  other  cocain  solutions  used  by  the  writer,  and  when  placed 
upon  a  pledget  of  cotton  and  pressed  into  the  interproximal  space 
gently  at  first  and  then  with  force,  the  relief  from  the  pain  of  removing 
the  serumal  deposits  is  marked.  It  may  here  be  said  that  the  strongest 
solutions  of  cocain  may  be  used  in  the  mouth  for  various  purposes 
without  danger  of  unpleasant  results  if  the  patient  is  instructed  not  to 


OBTUNDENTS. 


497 


Fig.  352. 


Fig.  353. 


Fig.  354. 


Fi«-  355- 


Fio.  357. 


Fig. 


Fig.  356. 
Description  of  Retainers. 
Fig.  349  illustrates  the  commonly  adopted  method  of  retaining  in  a  fixed  position  the 

lower  incisors. 
Fig.  350  shows  a  splint  retainer 

Figs.  351,  352,  353,  illustrate  the  retention  of  the  superior  six  anterior  teeth.     Fio.  351 
the  teeth  devitalized  and  prepared  to  receive  a  strong  post.     Fig.  352  shows  the 
retainer  before  adjustment.     Fig.  353  the  appliance  cemented  to  place  and  completed. 
354  shows  a  method  of  retention  for  posterior  teeth.     Pulps  usually  removed  and 
channi  Is  cut  in  the  occlusal  surfaces  for  a  strong  brace,  the  appliance  is  most  satis- 
factory when  the  channel  is  filled  as  an  inlay. 
Figs.  355,  356,  357  illustrate  the  authors  original  device  for  retention  of  loose  lower 
incisors.     Fig.  355  is  the  skeleton.     Fig.  356  the  lingual  aspect  after  completion. 
Fig.  357  the  labial  aspect  after  completion. 
The  description  and  making  of  this  retainer  is  as  follows: — 

Ligate  the  teeth  firmly  in  the  proper  position.  In  case.*  of  Pyorrhea  very  often  the 
position  of  the  teeth  is  changed,  but  they  can  be  ligated  and  placed  in  the  position  desired. 
The  next  step  is  with  the  proper  drills,  a  No.  i  round  bur  followed  by  No.  2,  make  a  hole 
through  the  upper  portion  of  the  tooth,  vrithin  about  an  eighth  of  an  inch  from  the  incisal 
edge  which  will  accommodate  21 -gauge  gold  wire.  When  these  cases  present  we  know 
very  well  the  horn  of  the  pulp  has  receded,  so  that  there  is  little  danger  from  encroach- 
ment upon  the  pulp.  The  next  step  is  to  take  an  impression  with  red  base  plate  gutta- 
percha of  the  lingual  aspect  of  the  teeth,  surround  this  impression  and  pour  upon  it  the 
low  fusing  metal,  which  can  be  done  in  a  very  few  minutes  In  this  way  a  very  good 
model  will  be  obtained.  Swage  upon  that  a  piece  of  22-karat  gold  plate  36  gauge,  place 
it  in  the  mouth,  and  indicate  with  an  instument  through  the  holes  where  the  pins  should 
be.  Punch  the  holes,  place  the  wire  and  solder  upon  the  lingual  side.  Then  put  it  in 
the  mouth  and  arrange  it  and  burnish  gold  to  fit  exact.  Use  pure  gold  if  desired.  Re- 
move this  very  carefully  without  changing  its  position.  Then  reinforce  with  solder  the 
lingual  side  until  suflBcient  strength  is  gained  Before  putting  it  on  finally,  grind  or  file 
the  plate  to  the  proper  shape  and  polish,  and  when  it  is  finally  completed,  place  the 
rubber  dam  upon  the  teeth  and  cement  it  in  place. 

After  the  cement  is  thoroughly  hardened,  cut  off  the  pins  and  rivet  them  with  a  round 
smooth  burnisher  in  the  engine,  dress  off  the  extra  cement  and  the  operation  is  completed. 
There  is  no  other  appliance  for  the  retention  of  the  lower  front  teeth  that  is  so  delight- 
ful and  permanent  and  that  is  so  readily  cleansed.  All  the  gold  that  shows  is  the  end  of 
the  2i-gauge  gold  wire,  which  cannot  be  seen  by  any  one  standing  two  or  three  feet  from 
the  patient. 

[The  above  supposed  original  device  for  retention,  the  author  finds  should  be  credited  to 
Dr.  \V.  H.  Trueman,  of  Phila.  who  described  the  same  in  Dental  Cosmos  of  1895,  p.  607.] 


498  PYORRHEA   ALVEOLARIS. 

swallow  one  drop  of  saliva,  but  to  eject  every  particle  of  mouth  fluids. 
The  mixtiire  is  also  forced  into  the  pockets  with  the  delicate-pointed 
syringe,  and  thus  penetrates  deeper  than  when  introduced  with  a 
broach  wound  with  a  shred  of  cotton. 

Dr.  Austin  James,  of  Chicago,  recommends  a  method  of  further 
rendering  the  use  of  scaling  instruments  less  painful,  by  polishing  all 
portions  of  the  diseased  root  with  various  forms  of  wood  points  used  in 
a  porte-polisher  and  charged  with  pumice  and  phenol  sodique,  and 
burnishing  with  suitable  forms  of  burnishers.  A  test  of  this  method 
by  the  writer  has  given  most  excellent  results.  Before  this  polishing, 
if  there  are  large  plaques  of  salivary  concretions,  of  course  they  should 
be  dislodged.  Dr.  James  also  advises  that  only  this  polishing  be  done 
at  the  first  sitting,  and  that  in  a  day  or  two  the  sensitiveness  will  be 
less  than  if  the  instrumentation  immediately  followed  the  polishing. 

SURGICAL  TREATMENT. 

Now  comes  the  instrumentation,  and  it  may  at  once  be  said  that  the 
instrument  which  will  accomplish  the  work  of  removing  all  deposits 
and  irritant  matter  from  the  root,  leave  it  smooth  so  that  repair  tissue 
will  form  about  it,  and  do  this  with  the  least  mutilation  of  the  soft  tissue, 
is  the  instrument  to  be  advised.  In  all  operations  involving  the  gingi- 
val tissue  it  is  extremely  important  that  the  rope-like  border  surround- 
ing the  cervix  of  the  tooth  be  not  severed  or  mutilated,  on  account  of 
the  fact  that  with  serious  lesion  it  recovers  slowly  and  is  seldom  re- 
produced like  the  original.  So  the  instruments  must  be  of  a  form, 
strength,  delicacy  and  effectiveness  not  perhaps  demanded  for  any 
other  operation  in  dental  surgery. 

Until  in  recent  years,  the  instruments  used  and  advised  have  been 
chiefly  those  doing  their  work  with  a  pushing  motion.  In  1886  Dr. 
G.  V.  Black,  in  the  "American  System  of  Dentistry,"  wrote  as  follows: 
"The  instruments  for  this  operation  should  for  the  most  part  be  formed 
to  work  with  a  pushing  motion.  Curved  and  hooked  instruments 
formed  to  work  toward  the  hand  with  a  pulling  motion  may  be  of 
service  in  removing  the  bulk  of  the  larger  concretions  of  salivary  cal- 
culus, but  they  are  of  inferior  value  in  the  removal  of  the  last  portions 
of  the  deposits  or  for  serumal  deposits  high  up  under  the  gum.  For 
this  purpose  all  hook  instruments,  no  matter  how  delicately  formed 
should  be  discarded,  and  slender  points  made  to  work  with  a  pushing 
motion  substituted." 

The  advice  of  Dr.  Black,  in  the  experience  of  all  who  sought  to 


SURGICAL   TREATMENT.  499 

treat  pyorrhea  was  deemed  good;  and  while  various  instruments  with  a 
draw  motion  were  formulated,  they  were  found  generally  to  be  inade- 
quate, and  the  push  instrument  first  prominently  brought  to  notice  by 
the  late  Geo.  H.  Gushing  with  his  admirable  and  delicate  set  of  six 
scalers,  and  other  sets  with  modifications  of  the  Gushing  forms,  have 
been  the  reliance  of  nearly  all  who  operated  for  pyorrhea.  But  the 
instrument  with  a  pushing  motion  has  had  its  day.  Even  the  stoic 
cried  out  against  it.  It  was  the  despair  of  those  treating  the  disease 
with  the  push  instrument  to  daily  hear:  "Well,  my  teeth  can  go;  I'll 
never  stand  that  pain  again."  Notwithstanding- this,  many  patients, 
appreciating  the  beneficent  results,  would  return  and  submit  to  the 
subsequent  minor  operations  often  necessary  to  control  the 
situation.  In  the  meantime  those  who  appreciated  and  demanded 
more  humane  instruments,  upon  the  principle  of  placing  a  point  be- 
yond the  deposits  or  other  irritant  matter  and  displacing  it  with  a  draw- 
ing motion,  were  continually  advising  and  devising  less  painful  methods, 
and  with  the  result  that  more  perfect  results  with  less  pain  can  be  se- 
cured with  properly  formed  hook  instruments. 

The  dental  operator  has  many  times  in  the  past  expressed  opinions 
denying  the  possibility  of  bettering  methods  and  instruments,  but  sub- 
sequently they  have  been  so  improved  as  to  bear  little  resemblance  to 
what  was  once  considered  all  that  could  be  desired.  The  clumsy  and 
impracticable  instruments  used  by  Dr.  Riggs,  which  operators  at  that 
time  thought  were  well-nigh  perfect  for  the  cure  of  pyorrhea,  are  now 
nowhere  used  save  for  removal  of  larger  crusts  of  salivary  calculus,  and 
it  seems  to  us  an  astonishing  thing  that  Dr.  Riggs  secured  such  a  meas- 
ure of  success  with  them  without  first  entirely  dissecting  away  the  soft 
and  underlying  tissues  surrounding  the  root  of  a  tooth.  So  now  we 
find  that  the  vaunted  push  instrument  must  give  place  to  the  more  per- 
fectly constructed  draw  instrument,  which  avoids  pain  and  which 
leaves  the  surface  of  the  root  in  a  much  smoother  condition,  insuring 
better  repair  of  tissue. 

r  The  description  and  illustration  of  instruments  for,  the  treatment  of 
pyorrhea  alveolaris  which  have  been  evolved  by  various  inventors,  and 
which  have  led  to  more  or  less  of  success  in  removing  irritant  matter 
from  the  roots  of  teeth  and  brought  a  measure  of  success  to  the  origina- 
tors and  those  who  have  placed  reliance  upon  them,  is  not  the  purpose 
of  this  presentation;  but  it  is  the  purpose  to  present  in  the  following 
illustrations  forms  of  instruments  deemed  greatly  superior  in  effective- 
ness to  any  heretofore  offered,  their  use  causing  less  pain,  and  of  such 
shapes  that  all  surfaces  of  affected  teeth  can  be  scaled  and  smoothed, 


500 


PYORRHEA   ALVEOLARIS. 


JA 


l\ 


fW,        J\        An\ 


/v-^ 


rU         l\ 


^-A 


n 


Fig.  3S^- 


SURGICAL    TREATMENT. 


501 


<-A 


Fig.  359. 


502  PYORRHEA   ALVEOLARIS. 

which,  in  the  opinion  of  the  writer,  cannot  be  accomplished  with  in- 
struments heretofore  commonly  used  for  the  purpose. 

The  principle  upon  which  these  instruments  are  planned  can  only 
be  imperfectly  described,  but  may  be  outlined  as  follows:  The  work- 
ing point  is  a  delicate  yet  strong  hook,  designed  to  be  thrust  beyond 
the  plaques  of  calcic  matter,  which  are  drawn  towards  the  crown  of  the 
tooth,  thus  dislodging  and  removing  the  irritant.  Each  instrument 
is  so  formed  that  a  short  distance  from  the  hook  the  blade  rests  upon 
the  root,  and  thus  guides  and  steadies  the  working  point,  and  also  pre- 
vents undue  furrowing  of  the  root.  The  hook  is  rounded  upon  all 
corners  and  surfaces  save  upon  the  immediate  or  cutting  edge,  so  as 
not  to  tear  or  lacerate  the  soft  tissues.  The  great  variety  of  forms 
allow  the  operator  to  follow  the  tooth  contour  with  a  minimum  of  pres- 
sure upon  the  inflamed  tissue.  Thus,  the  extreme  apical  territory  can 
be  reached  and  operated  upon,  if  desired,  with  an  entrance  between 
the  gum  margin  and  the  root  of  not  more  than  a  thirty-second  of  an 
inch,  which  is  the  usual  distance  from  the  working  point  to  the  back  of 
the  hook.  These  instruments  have  little  spring,  the  great  variety  of 
shapes  precludes  that  necessity,  and  the  rigidity  enables  the  operator 
to  use  great  force,  which  is  often  essential  in  removing  deposits  which 
have  long  existed.  The  working  point  is  constantly  on  line  with  the 
handle  of  each  instrument;  thus  turning  or  slipping  is  prevented,  and 
greater  precision  without  undue  force  is  attained.  These  instruments 
have  but  recently  been  placed  upon  the  market.  (Figs.  358,  and  359.) 
The  inventor  is  Dr.  C.  M.  Carr. 

The  illustrations  show  some  of  the  primal  forms.  In  the  full 
set  each  primal  form  has  a  number  of  variant  angles  and  curves, 
with  which  different  but  allied  contours  of  each  root  and  cervix  can 
be  reached  most  perfectly  and  without  unnecessary  wounding  of  tis- 
sues. In  beginning  the  operation  of  scaling,  it  is  wise  to  select  only 
that  number  of  teeth  for  one  operation  which  can  be  entirely  finished 
at  the  sitting.  If  the  disease  is  in  the  incipient  stages,  frequently  a 
number  of  teeth  can  be  treated;  if  the  condition  is  in  the  advanced 
stages,  from  one  to  four  should  be  the  limit.  In  all  cases  each  opera- 
tion should  be  limited  to  an  hour,  for,  in  the  first  place,  whatever  the 
means  used  for  obtunding,  the  operation  is  more  or  less  painful;  the 
teeth  operated  upon  are  also  left  in  a  condition  acutely  sensitive  to 
thermal  changes,  and  if  many  teeth  are  treated  at  one  siting,  the  dis- 
comfort is  distressing  for  many  days  on  this  account,  so  it  is  surely 
best  to  confine  this  discomfort  and  the  pamful  scaling  to  a  limited  time 
and  a  limited  area  to  prevent  accumulated  discomfort  in  cervical  terri- 


MEDICATION.  503 

tory  on  account  of  thermal  irritation,  and  to  prevent  shock  from  the 
unavoidable  pain  of  the  operation.  With  the  correct  diagnosis  as  to 
the  extent  of  the  disease  and  the  selection  of  the  suitable  instruments, 
there  must  be  a  determination  upon  the  part  of  the  operator  that  the 
roots  selected  to  be  operated  upon  at  any  sitting  shall  be  entirely  freed 
from  irritating  deposits  and  the  surfaces  left  in  a  condition  to  en- 
courage the  new  tissue  of  repair  to  form.  The  surgical  part  is  not  com- 
plete upon  the  removal  of  deposits,  but  after  that  these  surfaces  should 
be  smoothed  and  polished  as  perfectly  as  may  be.  About  the  crowns 
and  the  cervix  of  the  tooth  engine  instruments  with  brushes,  strips, 
rubber  cones,  etc.,  of  a  great  variety  of  shapes,  are  applicable; 
beyond  the  gum  margin  hand  instruments  must  be  used.  The 
various  wood  and  other  points,  held  in  a  suitable  porte-polisher 
and  charged  with  an  abrasive,  must  reach  all  possible  surfaces. 
Experience  has  taught  that  the  time  spent  in  smoothing  the 
roots  is  well  worth  the  endeavor,  for  the  rapidity  and  permanency  of 
the  recovery  is  greatly  enhanced,  and  the  operation  cannot  be  con- 
sidered completed  until  as  much  time  is  given  to  the  polishing  as  to 
the  removal  of  deposits. 

The  polishing  concluded,  then  comes  the  removal  of  all  loosened 
detritus  with  the  hot  water  used  in  a  strong  force  syringe  with  slender 
special  points  which  will  reach  well  down  into  the  pockets;  these  points 
are  best  made  of  silver  or  German  silver,  and  can  be  fashioned  by  any 
instru  ment-  maker. 

MEDICATION. 

The  Pharmacopeia  has  been  searched  for  the  drugs  which  will 
best  assist  to  a  cure.  Each  operator  has  a  favorite  remedy  among 
the  germicides,  antiseptics,  or  stimulants.  Some  form  of  an  acid 
has  strong  supporters;  those  usually  relied  upon  are  sulphuric  acid  in 
the  form  of  the  aromatic,  and  lactic  acid.  There  can  be  little  doubt 
of  the  efficacy  of  the  acid  treatment  for  the  removal  of  broken-down 
tissue  and  the  stimulation  of  involved  alveolar  processes,  but  there 
is  a  very  grave  objection  to  the  use  of  the  acids,  on  account  of  the  fact 
that  the  exposed  necks  of  teeth  are  thereby  rendered  more  sensitive  to 
thermal  shocks.  The  surfaces  from  which  the  coating  of  deposit  is 
removed  in  any  event  are  a  source  of  great  discomfort  to  the  patient  in 
whatever  manner  they  may  be  treated,  and  as  the  acid  treatment  seems 
to  greatly  increase  this  tenderness,  the  writer  has  abandoned  its  use 
and  substituted  a  10  per  cent  solution  of  silver  nitrate,  which,  as  is  well 
known,  renders  those  surfaces  much  less  painful.     Indeed,  in  very 


504  PYORRHEA   ALVEOLARIS. 

depraved  conditions  and  pockets  of  this  disease,  wiien  the  discolora- 
tion is  not  an  objection,  a  saturated  solution  of  the  silver  nitrate  brings 
results  not  secured  with  other  drugs.  The  10  per  cent  solution  is  just 
short  of  the  discoloring  strength.  In  using  the  silver  solution  the  parts 
should  be  protected  from  saliva  for  a  iew  seconds.  After  this  treat- 
ment all  inflamed  and  diseased  gum  tissue  should  be  bathed  with  drugs 
or  combinations  of  drugs  which  stimulate  absorption,  act  as  counter- 
irritants  and  obtund  irritated  surfaces. 

This  completes  the  surgical  treatment,  and  if  the  different  pro- 
ceedings described  have  been  faithfully  performed,  the  cure  to  be 
in  time  established  now  rests  largely  with  the  patient.  This  is  an 
all-important  consideration,  for  it  is  patent  to  all  that  the  disease  will 
recur  if  conditions  permitting  the  original  trouble  are  not  entirely 
corrected.  Each  patient  must  be  thoroughly  imbued  with  the  plain  state- 
ment that  however  faithfully  the  surgical  operation  has  been,  there  can  be 
little  hope  of  more  than  transient  relief  unless  there  is  a  determination  that 
the  mouth  must  continually  be  kept  in  a  sanitary  state.     Observation 


Fig.  360. 

has  taught  us  how  hopeless  often  is  the  task  of  changing  habits  which 
are  ingrained  during  a  lifetime  and  betoken  a  lack  of  physical  clean- 
liness. Patients  suffering  from  pyorrhea  inust  be  taught  by  positive 
and  sometimes  abrupt  but  earnest  words,  that  when  they  declare  their 
mouths  receive  the  most  scrupulous  care,  they  are  simply  deceiving 
themselves,  and  that  the  supposed  care  must  be  doubled  and  trebled 
ere  a  hygienic  mouth  condition  will  be  present.  They  must  especially 
be  warned  that  the  mouth  must  be  cleansed  of  food  detritus  after  each 
meal,  and  that  once  during  twenty-four  hours  brushing  with  unlimited 
use  of  a  powder  for  three  minutes  must  faithfully  be  performed.  The 
usual  and  universal  swishing  and  dabbing  for  a  few  seconds  upon 
only  the  buccal  surfaces  must  be  shown  to  be  well-nigh  useless,  and 
that  especially  the  lingual  and  interproximal  surfaces  are  the  points 
most  needing  friction.  The  position  of  holding  the  brush  and  the 
cleansing  movements  can  best  be  shown  upon  the  actual  teeth  in  a 
skeleton  or  dummy.  The  brush  recommended  is  one  in  which  the 
tufts  of  bristles  stand  well  apart,  admitting  their  reaching  between 
the  teeth,  and  is  illustrated  in  Fig.  360.     After  the  brushing,  show 


SUBSEQUENT  TREATMENT.  505 

ni  the  mouth  how  the  gums  should  be  massaged  with  the  finger 
and  thumb,  firmly  pressing  the  receded  gum  toward  the  cervix,  thus 
pressing  foreign  matter  out  of  pockets  and  coaxing  it  to  its  original 
anatomical  position.  Finally,  direct  that  nothing  is  equal  to  the  cleans- 
ing and  exercise  and  scouring  in  mastication  of  fibrinous  foods,  and  that 
the  more  sensitive  the  gums  are  the  more  the  teeth  need  their  natural 
use.  There  is  scarcely  a  dental  arch  affected  with  pyorrhea  where  one- 
half  of  the  arch  does  not  exhibit  great  difference  in  the  disease  progress, 
and  it  will  be  found  that  the  worst  condition  is  invariably  upon  the 
side  not  used  or  little  used  in  mastication.  This  neglect  of  universal 
use  comes  of  habit,  but  more  often  because  of  a  defective  arch  or  ten- 
derness in  teeth  or  gums.  Patients  must  be  instructed  that  safety  lies  in 
the  use  of  all  teeth,  and  the  operator  must  see  to  it  that  he  has  rendered 
that  possible  not  only  in  correcting  the  gum  disease,  but  in  making 
faulty  arches  as  perfect  as  may  be  possible.  The  frequent  use  of  a 
mouth  wash,  preferably  a  salt  solution,  for  rinsing,  and  to  be  forced  into 
the  interproximal  spaces  with  a  blunt-pointed  strong  force  syringe, 
should  also  be  instituted.  A  trial  of  the  syringe  for  home  treatment  will 
soon  convince  any  observant  operator  that  therein  he  has  a  great  help 
toward  a  cure.  It  will  be  found  that  after  the  most  vigorous  rinsing  and 
brushing,  food  particles  and  matter  in  the  imperfect  interproximal 
spaces  are  dislodged  with  the  syringe  which  were  undisturbed  with  the 
brush.  Especially  is  the  syringe  to  be  used  until  repair  tissue  fills  the 
pockets  of  disease  with  new  material. 

SUBSEQUENT  TREATMENT. 

If  the  operation  has  been  well  done,  it  is  inadvisable  to  disturb  the 
pockets,  which  are  soon  filled  with  the  plasma  out  of  which  repair 
comes.  The  very  common  practice  of  frequent  probing  and  medicat- 
ing is  strongly  condemned.  Give  Nature  an  opportunity  to  do  the 
mending,  and  do  not  stab  the  protoplasm  thrown  from  the  nutritive 
vessels  with  medicine  or  touch.  In  sixty  or  ninety  days  examination 
should  be  made,  and  if  any  point  of  calcic  deposit  has  escaped  the  initial 
operation,  its  position  will  be  easily  indicated  by  an  inflamed  tissue. 
This  examination  will  also  determine  as  to  the  degree  of  care  being 
given  by  the  patient.  If  it  is  found  to  be  very  lax,  prove  it  so  by  asking 
the  patient  to  take  the  hand  glass,  and  with  a  suitable  instrument  remove 
the  cheesy  putrefactive  matter,  which  can  only  remain  under  careless 
brushing.  Then  comes  your  opportunity  for  a  lecture  containing 
few  words,  but  they  will  be  emphatic  in  explaining  the  uselessness  of 
any  possible  surgical  operation  unless  followed  by  directions  originally 


5o6  PYORRHEA   ALVEOLARIS. 

given.  Sometimes  we  find  those  instructions  entirely  forgotten  and 
their  repetition  asked.  On  the  other  hand,  do  we  find  that  great  care 
has  manifestly  been  observed,  never  fail  to  give  warm  compliment. 

SYSTEMIC  TREATMENT. 

When  pyorrhea  is  accompanied  with  any  predisposition,  whether 
hereditary  or  acquired,  which  lends  to  the  virulence  of  the  disease, 
such  systemic  treatment  for  the  correction  of  the  predisposition  as 
found  advisable  should  always  be  relegated  to  the  patient's  medical 
adviser.  It  is  a  breach  of  ethics  if  the  doctor  of  dental  surgery  invades 
the  general  field  of  medicinal  treatment  by  the  administration  of  in- 
ternal remedies  for  the  correction  of  faulty  metabolism  or  svstemic 
conditions  from  whatever  cause. 


CHAPTER   XXX. 
EROSION. 

BY  GEO.  W.  COOK,  D.  D.  S. 

The  word  erosion  is  taken  from  the  Latin  erodere,  which  means 
to  gnaw  away.  Under  some  conditions  the  term  is  appHed  to  ulcera- 
tion. In  geological  parlance  the  word  is  synonymous  with  denuda- 
tion. The  term  is  frequently  used  in  pathological  conditions  of  plants; 
as,  for  instance,  if  an  insect  has  stung  or  poisoned  a  plant,  causing  a 
loss  of  substance  to  a  particular  locality,  the  diseased  part  becomes  per- 
fectly smooth  on  its  surface;  this  process  is  also  called  erosion.  The 
word  is  likewise  occasionally  apphed  to  certain  conditions  of  the  mu- 
cous surfaces  of  tissue  where  it  is  aphthous.  In  some  of  the  ancient  med- 
ical writings  aphtha  and  erosion  were  commonly  used  as  meaning  one 
and  the  same  thing;  but  at  the  present  time  the  connotation  of  these 
two  terms  applies  to  different  conditions.  The  term  erosion,  as  ap- 
plied to  the  teeth,  is  usually  looked  upon  today  as  a  process  whereby 
certain  surfaces  of  the  teeth  gradually  disintegrate,  leaving  a  perfectly 
smooth  expanse.  However,  it  must  be  remembered  that  when  these 
surfaces  disintegrate,  that  is,  when  they  occlude  with  the  opposing 
teeth,  it  is  not  considered  erosion  but  abrasion. 

Dental  erosion,  as  it  is  understood  at  the  present  time,  is  for  the 
most  part  confined  to  certain  surfaces  of  the  teeth  in  which  only  the 
mucous  surfaces  of  certain  soft  tissue  come  into  direct  contact  with  the 
tooth  substance.  However,  it  has  been  observed  that  this  pathological 
process  sometimes  appears  on  tooth  substances  where  the  surface  of  a 
tooth  does  not  come  in  contact  with  the  soft  tissue.  Hutchinson,  of 
England,  applied  the  term  to  certain  conditions  where  the  incisal  edge 
of  a  tooth  showed  marked  imperfections  in  the  form  of  a  semilunar 
appearance;  a  tooth  in  which  these  conditions  are  found  we  speak 
of  as  the  Hutchinson  tooth.  But  this  in  the  stricter  sense  of  the  term 
is  not  erosion.  Dr.  G.  V.  Black,  of  Chicago,  associates  this  class  of 
condition  and  many  other  forms  of  congenital  imperfections  of  the 
teeth  with  atrophy;  but  in  no  sense  are  erosion  and  atrophy  alike. 

As  we  have  just  stated,  dental  erosion  is  now  used  to  mean  a  grad- 
ual wasting  away  of  tooth  substance,  leaving  the  surfaces  of  teeth 
as  if  they  had  been  carefully  polished.     The  condition  may  be  present 

507 


5o8  EROSION. 

on  only  one  tooth,  or  on  a  large  number  of  teeth,  sometimes  involving 
practically  the  entire  set  of  teeth.  Sometimes  it  appears  as  if  a  fine 
rat-tail  file  had  been  the  instrument  used  to  make  these  notches  or 
grooves.  The  condition  more  commonly  appears  in  the  anterior  teeth. 
The  labial  surface  of  cuspids,  laterals  and  central  incisors  are  the  ones 
that  are  most  commonly  involved  in  this  process.  It  may  attack  the 
lingual  surface  of  the  bicuspids  and  molars  along  the  gingival  border, 
but  this  is  by  no  means  as  common  as  on  the  buccal  surface.  My 
attention  vv^as  called  to  a  case  in  the  infirmary,  in  which  the  surface  of 
almost  every  tooth  in  the  mouth  was  involved.  I  think,  however,  that 
such  cases  are  very  rare  in  comparison  with  those  of  the  more  common 
attacks,  which,  as  I  have  already  stated,  usually  take  place  in  the  six 
anterior  upper  and  lower  teeth.  In  another  case  there  was  a  notched 
or  grooved  appearance  on  the  lingual  surface  of  a  lower  lateral  incisor, 
extending  diagonally  across  its  lingual  surface;  the  groove  starting 
on  the  mesial  and  extending  diagonally  from  the  upper  third  of  the 
incisal  edge  to  almost  a  point  of  the  juncture  of  the  enamel  with  the 
cementum,  and  in  the  deeper  portion  extending  well  into  the  dentin 
of  the  tooth. 

The  tooth  surface  that  becomes  involved  in  this  affection  is  ordinar- 
ily situated  where  there  is  friction,  which  is  made  by  the  tooth-brush 
or  some  other  like  means  of  cleansing  the  teeth.  It  might  also  be  said 
that  erosion  appears  in  individuals  who  have  never  known  the  use  of 
a  tooth-brush,  or  who  cleanse  their  teeth  by  any  other  means  such  as 
by  cnewing  food.  I  have  in  mind  two  cases  in  which  there  was  ex- 
tended involvement  in  the  ten  anterior  teeth  of  the  upper  jaws,  the 
individuals  claiming  that  they  had  never  used  a  tooth-brush,  or  any 
other  means  by  which  it  may  be  said  that  friction  could  play  a  part  in 
the  conditions  of  these  cases. 

So  far  as  the  writer  has  been  able  to  find  out,  John  Hunter,  of 
England,  in  hisnatural  history  of  "Human  Teeth,"  is  the  first  to  give 
a  description  of  this  affection.  Since  that  time  a  number  of  authors 
have  contributed  many  hypotheses  for  this  pathological  process,  and 
each  has  tried  to  explain  the  reasons  for  believing  that  such  and  such 
factors  are  the  real  cause  of  this  affection.  Hunter's  original  idea  was 
that  the  disease  was  inherent  in  the  tooth  substance  itself,  and  that 
the  disease  appeared  later  in  life  because  of  certain  circumstances, 
but  these  circumstances  he  did  not  account  for. 

Bell,  who  was  among  the  early  writers  upon  this  subject,  held 
that  this  process  was  a  mechanical  one.  This  author's  principal' 
reason  was  based  upon  the  circular  deposits  of  the  enamel  substance 


EROSION.  509 

Garretson  considered  the  difficulty  to  be  due  to  an  impression,  such  as 
that  from  inheritance,  upon  the  individual  at  the  time  of  the  formation 
of  the  enamel,  in  which  it  left  a  predisposition  in  the  tooth  substance 
to  the  formation  of  the  future  lesion.  Fox  laid  considerable  stress 
upon  the  fact  that  the  affection  was  due  to  the  friction  of  the  lip,  assisted 
by  the  saliva.  Harris  and  Taft  place  the  cause  as  due  to  an  acid 
condition  of  the  buccal  mucus.  Nuhn  explained  that  erosion  on 
the  cutting  edge  of  the  front  teeth  was  caused  by  an  acid  mucus  ex- 
creted from  certain  glands  in  the  tip  of  the  tongue.  Weal's  observa- 
tion was  that  this  afifection  never  occurred  on  the  lingual  surface  of 
teeth,  and  that  the  trouble  must  be  sought  on  the  buccal  and  labial 
surfaces.  His  explanation  of  this  was  that  the  folds  of  the  mucous 
membrane  of  the  dental  arch  gradually  become  narrower,  and  terminate 
with  a  ridge  of  connective  tissue  which  is  attached  to  the  necks  of  the 
bicuspid  and  molar  teeth,  a  condition  which  may  extend  along  the  facial 
surface  of  the  gums  of  the  lower  jaw. 

In  the  Dental  Cosmos,  1873,  Dr.  Charles  Koch  gave  a  descriptive 
explanation  of  the  difference  between  mechanical  abrasion,  caries, 
and  erosion  of  teeth.  He  believed  that  because  erosion  could  not  be 
produced  artificially  or  mechanically,  just  as  it  appeared  in  the  mouth, 
that  the  pathological  process  was  a  congenital  or  acquired  predisposi- 
tion aided  or  abated  by  chemical  reagents,  or  perhaps  by  mechanical 
means.  In  this  particular  there  seems  to  be  some  confusion  as  to 
just  what  the  author  did  mean. 

Baum  believes  that  where  the  dentin  of  the  tooth  is  not  covered 
by  gum  tissue  or  enamel,  this  exposed  surface  of  dentin  exfoliates  and 
mechanically  falls  out  of  its  position,  and  by  the  friction  of  the  lips  and 
brush  the  surface  of  the  tooth  becomes  polished.  In  1880,  W.  Finley 
Thompson  made  an  extensive  study  of  the  difference  between  caries 
and  erosion,  and  wrote  a  very  interesting  paper  on  this  subject  at  that 
time.  He  says,  "  caries  of  the  teeth  may  attack  apparently  strong  tooth 
structure  and  semi-decalcify  the  dentin  of  the  tooth,  which  will  retain 
with  great  tenacity  its  connections  with  the  normal  tooth  tissue,  but 
erosion  seems  fated  to  complete  disorganization  and  this  continues 
until  considerable  surface  of  the  tooth  is  destroyed,  leaving  a  polished 
surface." 

Dr.  Edwin  T.  Darby  expressed  his  opinion  that  the  general  affec- 
tion known  as  erosion  was  produced  by  an  acid  in  the  buccal  mucosa, 
which  was  intimately  associated  with  rheumatic  and  gouty  conditions. 
C.  Edmund  Kells  expresses  the  belief  that  it  is  due  to  an  acid  excreted 
by  the  mucous  glands  on  the  labial  and  buccal  sides  of  the  teeth. 


5IO  EROSION. 

Fairbanks,  of  England,  laid  stress  on  the  fact  that  erosion  of  the  teeth 
was  due  to  the  decomposition  of  undigested  food  in  the  stomach,  and 
usually  appeared  in  mouths  that  were  exceptionally  clean.  Stockton 
held  the  opinion  that  erosion  of  the  teeth  was  due  to  certain  gouty 
conditions  which  produced  a  general  acidity,  and  that  an  alkaline  tooth 
powder  arrested  the  progress  of  the  disease.  Bailey  laid  considerable 
stress  on  the  mechanical  action  of  the  fluids  of  the  mouth.  He  says: 
"In  the  first  place,  all  cases  of  erosion  are  in  a  position  subject  to  the 
action  of  the  oral  fluid  currents,  which  take  varying  directions  in  dif- 
ferent mouths  and  even  in  the  same  mouth."  He  further  says:  "We 
know  that  a  running  stream  can  easily  be  changed,  and  in  this  way  we 
are  liable  to  have  the  mechanical  friction  produced  by  the  current  of 
flow  of  the  fluids  of  the  mouth." 

Billetter,  of  Zurich,  also  holds  to  the  mechanical  theory.  W.  H. 
Trueman  believes  that  it  is  due  to  chemo-vital  causes  and  that  the  ex- 
creting of  the  fluid  is  necessarily  a  chemical  process.  The  idea  that 
this  destructive  agent  must  be  an  acid  having  affinity  for  the  lime  salts 
of  the  teeth  has  but  little  tradition  to  support  it.  The  little  cap  which 
we  frequently  see,  mainly  of  enamel,  and  all  that  remains  of  a  baby 
molar,  is  sufficient  evidence  that  there  may  be,  and  is,  formed  in  the 
oral  cavity  a  true  solvent  of  tooth  tissue.  This  effect  has  been  pro- 
duced by  a  normal  physiological  process.  He  further  suggests  the 
stomachic  digestion  as  being  parallel  to  erosion  and  excludes  "chem- 
ism"  as  being  only  a  minor  agent.  Prof.  James  Truman  considers 
the  process  of  erosion  and  abrasion  as  extremely  simple;  he  says  that 
they  are  governed  by  the  law  of  chemical  action  and  that  erosion  is 
unquestionably  the  result  of  a  chemical  solution. 

Dr.  G.  V.  Black,  in  the  American  System  of  Dental  Surgery, 
published  the  results  of  some  experiments  in  using  the  dilute  solution 
of  hydrochloric  acid  1-400.  He  recorded  in  one  experiment  how  he 
took  two  fresh,  healthy  bicuspids  and  covered  the  greater  portions  of 
them,  roots  and  all,  with  gutta-percha,  exposing  only  the  crown. 
These  were  then  placed  in  a  jar  containing  diluted  hydrochloric  acid, 
the  teeth  being  arranged  in  such  a  way  that  the  current  would  im- 
pinge upon  the  outer  surface  of  one  tooth  with  greater  force  than  upon 
the  other.  This  resulted  in  the  disappearance  of  the  cusps  and  the 
formation  of  the  groove  between  the  teeth.  The  groove  was  more 
marked  upon  the  one  receiving  the  greater  force  of  the  current.  A 
large  number  of  other  observations  were  carried  out  and  it  was  found 
that  the  strong  solutions  produced  general  softening  of  the  teeth, 
while  a  solution  of  i  of  acid  in  5000  of  water  had  no  appreciable  effect 


EROSION.  511 

after  three  months.  Dr.  Black,  however,  did  not  try  this  experiment 
with  any  other  substance  than  hydrochloric  acid.  I  tried  to  duplicate 
Dr.  Black's  experiments  but  did  not  get  the  marked  effect  that  I  had 
expected.  I  took  a  U-shaped  tube  that  was  somewhat  similar  to  the 
tube  used  in  the  apparatus  designed,  by  Kohlrausch.  In  this  tube 
was  placed  a  perfectly  sound  tooth,  of  which  all  but  a  small  portion 
was  covered  with  wax.  Various  solutions  of  acids  and  neutral  salts 
were  placed  in  this  tube  and  an  electrical  current  was  passed  through 
these  solutions  at  alternate  intervals.  It  was  found  that  all  the  neutral 
salts,  with  but  one  or  two  exceptions,  did  not  produce  any  disintegra- 
tion of  tooth  substance.  But  all  of  the  acids,  even  though  they  were 
in  the  most  diluted  form,  did  produce  disintegration  of  the  tooth  sub- 
stance when  a  mild  current  was  passed  through  the  solution.  There 
are  so  many  points  of  physical  chemistry  that  enter  into  this  process 
that  it  would  be  quite  out  of  place  to  detail  them  here.  But  we  might 
say  this,  that  the  conductivity  of  saliva  differs  in  different  individuals, 
and  that  those  suffering  from  dental  caries  have  a  saliva  with  a  high 
conductivity,  which  shows  that  there  might  be  some  of  the  strong  acids 
present;  while  in  the  simpler  form,  or  we  might  say  in  the  mild  forms 
of  erosion,  the  saliva  has  a  low  conductivity,  showing  that  there  is  some 
difference  in  either  the  acids  or  basic  salts  in  the  colloids  in  the 
saliva.  The  organic  acids  affect  teeth  very  differently  when  an  elec- 
tric current  is  passed  through  the  solution  from  the  way  the  mineral 
acids  (monobasic  acid)  affect  them. 

The  above  observations,  to  a  certain  degree,  help  to  substantiate 
the  electrical  theory.  In  other  words,  in  the  saliva  of  mouths,  whether 
or  not  we  have  acids,  we  have  many  of  the  electrolytic  salts  which  ex- 
ist there  not  as  salts  so  much  but  as  associated  ions.  This  means  that 
an  atom  of  sodium,  potassium,  magnesium,  etc.,  is  charged  with  elec- 
tricity. Therefore,  they  are  in  constant  motion  in  the  solution,  it 
matters  not  how  apparently  quiet  the  solution  may  be.  The  substance 
in  the  saliva  containing  the  negative  ions  is  constantly  passing  and 
combining  with  the  ions  of  a  positive  nature.  Consequently  all  the 
fluids  of  the  body  that  contain  electrolytic  salts  are  constantly 
producing  molecular  activity  of  the  solution.  Thus,  in  the  acids, 
atoms  that  make  up  the  acid  groups  in  the  saliva  have  a  very  low 
activity. 

Tomes  was  of  the  opinion  that  the  true  and  only  cause  of  the  diffi- 
culty was  a  mechanical  one.  Schlenker,  Walkoff,  Scheff,  Bastyr  and 
Brandt  have  all  expressed  their  opinions  that  the  disease  is  the  result 
of  a  chemo-mechanical   process.     They  have   placed   stress  on   the 


512  EROSION. 

chemical  side  of  the  question,  thus  suggesting  that  its  one  cause  is  a 
thin  layer  of  decalcification  of  tooth  substance,  which  is  removed  by 
the  cleansing  process. 

Miller's  recent  investigation  seems  to  indicate,  from  his  view- 
point, that  the  mechanical  action  of  substances  such  as  tooth  powders, 
or  any  agents  that  will  produce  friction,  is  the  main  factor  in  causing 
the  wearing  away  of  the  surfaces  of  teeth.  From  all  the  observations, 
with  but  few  exceptions,  it  seems  to  me  that  this  is  true.  However, 
there  are  physical  and  chemical  properties  of  saliva  that,  beyond  any 
question  of  doubt,  must  play  some  r61e  in  this  obscure  process.  I 
have  in  only  a  few  instances  been  able  to  produce  the  eroded  surface 
exactly  as  it  appears  in  the  mouth.  I  have  produced  erosion  of  teeth 
with  practically  all  of  the  tooth  powders  and  mouth  washes  that  are 
today  on  the  market,  but  in  the  vast  majority  of  instances  it  does  not 
appear  identical  with  the  cases  found  in  the  human  mouth.  I  have 
in  mind  a  patient  suffering  from  erosion,  in  whom  the  care  of  the 
mouth  has  been  practically  neglected,  so  far  as  brushing  the  teeth  is 
concerned.  She  tells  me  that  she  was  trained  from  childhood  up  not 
to  scrub  her  teeth,  but  to  wash  them  with  a  smooth,  soft  cloth,  and  to 
do  so  once  or  twice  a  week  only.  The  rest  of  the  time  the  mouth 
had  no  care  except  a  rinsing  with  water.  She  has  well-defined  eroded 
surfaces  on  the  cuspids,  lateral  and  central  incisors,  and  more  recently 
on  the  bicuspids.  This  case,  with  similar  observations,  would  hardly 
justify  us  laying  much  stress  upon  the  mechanical  cause  of  erosion 
of  tooth  surfaces.  I  think  the  majority  of  observations  that  have 
been  recorded  are  to  the  effect  that  the  diverted  activity  of  the  mucous 
glands  is  the  principal  cause  of  the  disease.  This  is  the  most  preva- 
lent opinion  held  by  the  majority  of  writers  upon  the  subject;  and 
beyond  any  question  of  doubt  in  my  mind,  it  is  to  an  explanation  of 
this  nature  that  we  are  to  look  for  the  best  light  on  this  pathological 
lesion. 

W.  X.  Sudduth  brought  forth  the  hypothesis  that  this  affection 
was  due  to  a  lowered  nervous  condition  which  resulted  in  a  salivary 
acid.  There  may  be  an  element  of  truth  in  this  statement.  According 
to  the  investigation  of  Halliburton  most  all  tissue  contains  a  mucoid- 
like  substance;  and  according  to  J^Iorner  there  is  to  be  found  in  such 
tissues  a  chondromucoid,  which  has  the  composition  of  the  following 
elements:  C.  47.30,  H.  6.42,  N.  12.58,  S.  2.42,  O.  31.28.  When 
this  is  extracted  from  the  tissues  it  has  an  acid  reaction  and  becomes 
insoluble  in  water.  If  it  were  possible  to  take  living  tissue,  the  activity 
of  which  is  largely  confined  to  excreting  a  mucoid-like  substance 


EROSION.  513 

we  should  find  that  this  tissue  goes  through  certain  chemical  reactions 
in  which  hydrogen  plays  an  important  part. 

There  are  a  number  of  acid  molecules  which  appear  in  the  chem- 
ical manipulation  of  that  group  of  acids  belonging  to  glycuronic  acid. 
Galactose  is  also  present  in  mucoid  substances,  occurring  for  most 
part  among  the  hexoses.  When  split  apart  the  latter  will  yield  dextrin 
and  furfurol,  which  can  be  oxidized  into  mucic  acid.  In  the  Dental 
Review,  May,  1906,  was  published  a  brief  article  entitled,  "The  Role 
Played  by  Certain  Acid  Derivatives  of  Lactose  in  Erosion  of  Teeth." 
At  that  time  I  was  strongly  of  the  opinion  that  mucic  acid  would  dis- 
solve tooth  substance  with  perhaps  a  degree  of  success.  But  an  in- 
teresting fact  developed  that  this  acid  was  easily  and  rapidly  broken 
up  by  certain  bacteria,  and  especially  by  those  that  are  constant  in- 
habitants of  the  oral  cavity.  Thus  it  was  found  that  mucic  acid  had 
to  be  kept  under  aseptic  conditions  when  acting  on  the  tooth  sub- 
stance, otherwise  it  became  quickly  broken  up,  forming  alkali  that 
did  not  affect  the  tooth.  It  was  also  found  that  the  teeth  had  to  be 
kept  in  fresh  solutions  of  the  reagent,  for  as  soon  as  it  had  acted  for  a 
few  hours  on  a  tooth  it  extracted  enough  of  the  neutral  salts  out  of  the 
tooth  substance  to  neutralize  the  mucic  acid  solution.  I  have  also 
noted  a  vast  difference  in  the  teeth  to  be  acted  upon  by  the  mucic  acid 
as  well  as  many  other  agents,  and  that  some  teeth  are  far  more  easily 
acted  upon  by  an  agent  than  others. 

As  I  have  stated  before,  experimentally  I  can  produce  erosion  with 
a  large  number  of  agents,  but  I  have  never  yet  been  able  to  produce 
any  but  what  were  atypical,  rather  than  typical,  by  anything  except 
mucic  acid. 

However,  it  will  be  remembered  that  galactose  is  not  always  one 
of  the  derivatives  of  the  hydrolytic  splitting.  In  the  article  above  men- 
tioned, it  was  shown  that  the  saliva  might  contain  relatively  large 
quantities  of  mucoid  substance,  containing  the  precursor  of  mucic 
acid;  and  by  hydrolytic  oxidation  these  substances  would  easily  give 
rise  to  mucic  acid.  For  instance,  in  such  conditions  as  pregnancy, 
and  various  other  constitutional  changes  in  which  these  agents  are 
present,  this  combined  material  might  under  favorable  circumstances 
produce  what  is  usually  designated  as  acidosis  and  hyperacid  secre- 
tions of  the  mouth,  which  might  furnish  a  mucin  easily  oxidized  into 
the  various  agents  above  mentioned.  I  am  now  more  convinced  of 
the  possibility  of  such  changes  being  so  produced  than  I  was  at  the 
time  the  article,  referred  to,  was  published. 

I  followed  experiments  on  animals  by  bathing  the  mucous  surfaces 


514  EROSION. 

for  a  considerable  time,  using  many  times  friction  with  various  agents. 
It  was  observed  that  many  of  the  substances  that  we  use  for  the  pur- 
pose of  producing  disinfection  of  the  oral  cavity,  when  used  at  inter- 
vals for  some  time  on  the  mucous  surface,  produced  degeneration  of 
the  tissue  cells.  The  tissue,  removed  and  stained  by  me,  immediately 
gave  an  acid  reaction.  The  micro-chemical  process  is  one  which  at 
the  present  time  is  looked  upon  as  one  of  the  valuable  means  of  deter- 
mining the  alkalinity  or  acidity  of  the  tissue  elements.  It  would  be 
quite  out  of  place  here  to  give  the  methods  used  in  this  connection. 
Suffice  it  to  say  that  any  one  who  is  interested  in  this  phase  of  the 
subject  is  referred  to  the  work  of  Cross  and  Bevan. 

According  to  the  investigation  carried  out  by  Acree  and  Hinkins, 
they  found  that  acid  saliva  containing  sufficient  amount  of  acid  to  pro- 
duce erosion  or  wasting  away  of  tooth  substance  may  flow  directly 
from  the  salivary  glands.  In  nearly  all  of  the  works  on  physiology 
we  are  told  that  the  saliva  may  be  neutral  or  alkaline  under  ordinary 
circumstances;  but,  according  to  the  investigations  of  the  authors 
just  mentioned,  acid  saliva  is  more  common  than  we  are  ordinarily 
led  to  believe.  It  is  not  only  possible  for  the  mucous  membrane  to 
have  an  acid  reaction  given  off  from  it;  but  it  is  also  possible  for  the 
saliva,  taken  directly  from  the  salivary  glands,  to  contain  acid  in  suffi- 
cient quantity  to  give  a  reaction.  Many  times  the  acidity  of  the  saliva 
taken  from  the  salivary  glands  contained  as  much  acid  as  was  found 
in  the  oral  cavity  where  it  had  been  under  the  influence  of  bacterial 
changes. 

All  of  this  goes  to  show  conclusively  that  the  body  substance,  under 
ordinary  circumstances,  and  that  certain  organs  and  tissues,  are  spe- 
cially subjected  to  certain  physiological  changes  that  bring  about  an 
acid  condition  of  the  cells  and  tissues,  as  well  as  of  the  organs  from 
which  the  secretion  is  taken. 

The  investigations  by  McGuigan  and  myself  have  clearly  demon- 
strated to  my  mind  that  we  seldom,  if  ever,  have  lactic  acid  present  in 
the  oral  cavity.  With  all  of  the  tests  we  could  make,  by  electrical 
conductivity  and  by  optical  determination,  in  which  we  polarized  the 
saliva  that  was  acid,  we  did  not  find  an  optically  active,  lactic  acid. 
From  these  and  other  tests  we  are  led  to  believe  that  the  acid  saliva 
of  individuals  affected  by  erosion,  and  of  many  suffering  from  dental 
caries,  does  not  contain  lactic  acid.  However,  I  might  say  that  we  did 
take  the  scrapings  from  decayed  teeth  and  placed  them  on  a  micro- 
scopic slide  and  found,  with  the  addition  of  metallic  zinc,  that  had  been 
previously  prepared  for  this  purpose,  that  there  were  crystals  formed 


TREATMENT    OF    EROSION.  515 

that  gave  the  appearance  of  lactate  of  zinc  crystals.  But  our  work 
on  this  particular  phase  did  not  give  very  satisfactory  explanation  as 
to  the  kind  of  the  acid. 

There  were  so  many  isomers  of  lactic  acid  formed  and  these  dif- 
fered so  materially  from  the  molecule  formation,  one  from  the  other, 
that  it  was  extremely  difficult  to  say  whether  or  not  we  had  a  lactic 
acid  or  some  other  organic  acid  present.  We  found  many  crystals 
that  assumed  practically  the  shape  of  the  zinc  lactate  crystals.  I 
think  a  careful  review  of  the  work  of  Hinkins  and  Acree  will  show  that 
the  crystals  formed  under  such  circumstances  are  very  unreliable. 
Owing  to  the  lack  of  space  we  cannot  discuss  this  phase  of  the  subject 
at  this  time;  suffice  it  to  say,  however,  that  our  opinion  up  to  the  pres- 
ent time  is  that  lactic  acid  does  not  play  any  role  in  the  cause  of  ero- 
sion of  teeth.  We  are,  however,  of  the  opinion  that  an  acid  is  present 
in  all  of  these  conditions,  but  that  in  the  majority  of  instances  friction 
must  be  applied  in  order  that  the  dissolution  of  the  surface  of  these 
teeth  will  assume  a  smooth,  glassy-like  appearance. 

Monobasic  acids  never  give  a  typical  eroded  surface.  The  acids 
that  come  the  nearest  to  giving  a  typical  erosion  are  those  organic 
acids  that  contain  the  largest  number  of  the  hydroxyl  group. 

If  we  review  with  care  these  theories  which  I  have  quoted,  it  will 
be  observed  that  all  these  theories  deal  with  but  one  or  perhaps  two 
factors.  The  work  I  have  done  leads  me  to  but  one  conclusion,  and 
that  is  we  have  dealt  with  this  problem  in  an  elementary  way.  It 
should  be  remembered  that  all  vital  processes  are  of  a  complex  chem- 
ical nature,  and  that  erosion  of  teeth  is  a  physico-chemical  change  of 
a  greater  complexity  than  most  of  those  that  have  been  suggested  up  to 
the  present  time.  I  can,  as  has  already  been  stated,  produce  erosion 
with  almost  anything,  even  whh  water  and  a  stick,  but  it  is  not  typical 
under  the  microscope.  Therefore  we  cannot  say  but  what  erosion  of 
tooth  substance  is  a  complex  process  and  not  a  simple  one,  in  the  sense 
that  most  writers  have  placed  this  subject. 

TREATMENT  OF  EROSION. 

The  treatment  of  erosion  is  for  the  most  part  mechanical,  and  in- 
volves the  cutting  out  of  the  eroded  surface  and  the  filling  it  in  the 
ordinary  way.  One  of  the  great  advances  made  in  dentistry  is  that 
of  the  application  of  porcelain  in  just  this  class  of  cases.  However^ 
I  have  met  with  considerable  success  in  using  certain  agents  in  the 
treatment  of  this  affection,  and  my  greatest  success  has  principally 
been  in  the  use  of  nitrate  of  silver,  especially  in  the  first  stages  of  this 


5l6  EROSION. 

process.  In  the  early  use  of  this  agent  I  thought  its  effects  were  pro- 
duced by  its  action  on  the  eroded  surface  of  the  tooth,  but  later  I  ob- 
served that  its  benefits  were  principally  due  to  the  action  that  it  had 
on  the  mucous  secretions  in  the  location  where  the  treatment  was  ap- 
plied. In  other  words,  when  the  treatment  was  applied  to  the  eroded 
surface  of  a  tooth,  it  would  necessarily  come  in  contact  with  the  mucous 
glands,  and  in  this  way  change  the  secretions  of  these  glands;  so  that 
whatever  chemical  agent  was  acting  upon  the  tooth  surface  was  in 
some  way  or  other  destroyed. 

Dr.  D.  M.  Cattell  called  my  attention  to  a  case  in  his  practice  in 
which  I  advised  the  use  of  nitrate  of  silver,  as  a  painting  over  the 
mucous  surface  which  came  in  contact  with  the  eroded  portion  of  the 
tooth.  He  followed  this  treatment  at  intervals  for  six  months  or  a  year, 
and  he  tells  me  that  the  erosion  has  practically  subsided.  The  care 
of  the  patient's  mouth  has  been  just  the  same  as  it  had  been  previous 
to  the  treatment  with  nitrate  of  silver.  This,  with  a  number  of  other 
cases,  demonstrates  to  my  mind  that  we  have  to  look  to  the  mucous 
surface  more  or  less  for  the  stoppage  of  this  process. 

There  are  certain  forms  of  tooth  degeneration  that  are  not  strictly, 
in  all  respects,  like  that  of  erosion.  Sensitive  cavities  appear  at  the 
gingival  margin,  so  sensitive  many  times  that  it  is  quite  impossible  to 
touch  them.  This  class  of  cases  sometimes  can  be  successfully  treated 
with  the  application  of  a  saturated  solution  of  caustic  alkalies  like 
sodium  and  potassium  hydrate.  After  two  or  three  applications  of 
this  saturated  solution,  from  one  to  three  days  apart,  take  a  dull 
engine  bur  and  run  it  over  these  surfaces  at  a  rapid  speed,  which  will 
lessen  the  sensitiveness  of  the  cavity.  If  such  applications  do  not 
sufl&ce  to  relieve  or  arrest  this  process,  then  a  saturated  solution  of 
silver  nitrate  should  be  applied.  When  the  discoloration  from  the 
silver  nitrate  has  fully  formed,  which  always  gives  an  unsightly  ap- 
pearance, an  application  of  tincture  of  iodine  to  the  discolored  tooth 
tissue,  followed  by  ammonia,  will  usually  remove  all  the  stain.  In  the 
application  of  nitrate  of  silver  to  eroded  surfaces,  regardless  of  where 
these  surfaces  may  appear,  I  use  a  saturated  solution.  I  then  remove 
the  stain,  in  the  manner  above  described,  or  by  polishing;  the  former 
being  much  better  than  the  latter. 

In  writing  this  article  I  have  tried  to  weigh  with  care  the  theories 
and  ideas  heretofore  held  by  different  authors  regarding  the  cause  of 
erosion.  I  have  only  quoted  from  those  who  seem  to  give  the  most 
reasonable  hypotheses  on  the  subject.  I  have  arranged  the  subject 
matter,  as  near  as  possible  so  that  the  readers  might  analyze  the  sub- 


TREATMENT    OF    EROSION.  $17 

ject  for  themselves,  and  possibly  aid  them  in  a  more  careful  observa- 
tion of  the  cases  that  come  under  their  care.  Time  and  space  do  not 
permit  me  to  quote  all  of  the  writers  upon  the  subject  as  I  should  like. 
Suffice  it  to  say  that  much  of  the  material  that  has  been  written  is 
very  hard  to  analyze  and  secure  the  exact  interpretation  of  the  authors' 
ideas  and  just  what  was  being  formulated. 


CHAPTER  XXXI. 
THE  MANAGEMENT  OF  AN  OFFICE  PRACTICE. 

BY    ELLISON   HILLYER,    D.    D.    S.,    SC.    D. 

When  college  and  state  board  requirements  have  been  fulfilled 
the  graduate  student  faces  the  problem  of  applying  the  result  of  his 
preparatory  training  to  its  ultimate  object — the  practice  of  his  pro- 
fession. 

Two  paths  open  before  him;  either  he  may  enlist  as  the  assistant 
of  another  practitioner  with  the  aim  of  acquiring  by  close  contact  that 
experience  which  only  the  atmosphere  and  surroundings  of  an  office 
can  give;  or  he  may  elect  to  begin  at  once  his  career  upon  his  own  ac- 
count, relying  upon  his  college  training  as  sufficient.  In  either  case  it 
is  but  a  beginning  and  each  should  feel  that  nothing  but  an  assiduous 
devotion  to  the  highest  ideals  and  constant  pursuit  of  further  knowl- 
edge can  lead  to  any  measure  of  success. 

By  the  time  a  student  has  received  his  degree  and  license  to  prac- 
tice he  should  have  learned  to  regard  his  profession  as  among  the  most 
dignified  and  worthy  of  all  he  can  give  to  it.  If  a  student  regards  it  as 
but  "  a  means  to  an  end  "  he  should  press  the  question  further  and  ask 
himself  "what  is  the  end?" 

He  has  probably  heard  it  said  many  times  that  he  will  hardly  grow 
wealthy  by  the  practice  of  dentistry  alone;  if  wealth  is  what  he  seeks, 
then  let  him  choose  some  other  path.  The  status  of  the  profession 
was  never  elevated  by  one  of  its  members  seeking  affluence  through  its 
channels  but  it  has  been  raised  to  its  present  high  position  by  the  self- 
sacrifice  of  those  who  have  given  more  to  it  than  it  to  them. 

Imbued  with  this  spirit  and  settled  in  conviction  as  to  just  what 
"success"  really  means,  let  each  go  forth  prepared  to  do  all  in  his 
power  for  those  who  will  come  into  his  care;  let  him  remember  that  he 
has  been  trained  to  serve  and  that  it  is  his  place  to  give  the  best  that  is 
in  him  with  no  thought  of  the  public  as  existing  for  his  benefit. 

Were  this  spirit  to  animate  all  our  graduates  the  quackery  which  is 
the  bane  of  our  profession,  as  it  is  of  all  professions,  would  cease  to  exist. 
The  beginner  argues  that  "he  must  make  his  living"  and  proceeds  to 
make  it  by  whatever  means  present.  This  is  short  sighted  as  no  great 
success,  in  the  highest  sense,  was  ever  achieved  by  lightning  strides  but 

519 


520  THE    MANAGEMENT   OF   AN    OFFICE   PRACTICE. 

by  slow  consistent  proceeding.  Thus  only  can  a  man  hold  his  place  as 
a  professional  man.  If  he  prefers  to  prostitute  his  ideals  and  make  of 
his  profession  a  "business,"  with  fillings  and  dentures  at  so  much  per 
filling  and  denture — that  "so  much"  being  usually  as  much  as  he  can 
make  the  patient  pay — he  must  be  satisfied  to  take  his  place  outside 
the  professional  pale  and  realize  he  has  none  but  himself  to  blame. 

In  the  locating  of  his  prospective  office  the  student  has  to  consider 
several  things;  surroundings,  ease  of  access,  availability  of  space  and 
arrangement  of  reception  and  operating  rooms.  Of  the  first  two  noth- 
ing need  here  be  said;  of  the  latter  much  might  be  noted. 

For  the  best  results  three  rooms  are  needed;  the  reception  room, 
operative  office  and  prosthetic  laboratory.  To  the  first  may  well  be 
added  a  retiring  room  fitted  with  various  toilet  requisites.  The  recep- 
tion room  should  be  made  as  attractive  as  possible.  The  general  atmos- 
phere should  be  one  of  refinement  and  good  taste  with  everything  to 
detract  from  the  unpleasant  side  of  a  visit.  Good  literature,  maga- 
zines and  books  should  be  at  hand  to  occupy  any  spare  moments  of  a 
waiting  patient.  Attractive  fittings  and  interesting  pictures  should  be 
provided  to  catch  the  eye  and  by  suggestion  take  the  attention  of  the 
patient  away  from  himself.  Have  some  one — preferably  a  lady — in 
attendance,  as  much  more  ease  is  given  to  both  patient  and  operator 
by  the  judicious  services  of  a  competent  lady  assistant. 

In  the  fitting  of  the  operating  room  two  plans  are  offered ;  one  upon 
the  design  of  a  general  surgical  operating  room,  accomplished  by 
having  a  cement  or  inlaid  floor,  enameled  walls  and  ceiling,  enam- 
eled iron  chair  with  leather  fittings,  enameled  iron  cabinet,  etc.,  with 
glass  for  all  shelf  work.  While  white  enamel  is  usually  chosen,  any 
color  scheme  in  enamel  may  be  carried  out  in  the  finish  of  chair,  cabi- 
net and  operating  apparatus.  These  fittings  are  all  obtainable  and 
make  an  admirable  outfit  for  anyone  who  cares  to  go  to  that  extent. 

The  other  plan  admits  of  cheerful  surroundings;  hard  wood  floors 
with  rugs,  pleasing  draperies  and  pictures  with  the  use  of  glass  wher- 
ever instruments  are  to  come  in  contact  with  tables,  brackets,  etc.  Several 
illustrations  of  offices  may  be  found  in  the  pages  of  the  Items  of  In- 
terest, Vol.  XXI,  which  would  give  many  valuable  ideas  to  beginners 
regarding  the  fittings  of  an  office. 

Difference  of  opinion  exists  as  to  the  proper  size  of  the  operat- 
ing room;  this  need  be  no  larger  than  is  required  for  the  operator  to 
stand  by  the  operating  chair  within  easy  reaching  distance  of  the  in- 
strument cabinet,  dental  engine  apparatus  and  electrical  equipment; 
much  time  is  saved  by  having  everything  within  easy  reach.     When 


THE    MANAGEMENT    OF    AN    OFFICE    PRACTICE. 


521 


a  larger  room  is  used  this  same  arrangement  should  still  he  maintained 
about  the  chair  while  other  appurtenances,  such  as  an  office  laboratory 
work-bench,  tables  for  porcelain  furnaces  and  an  ofhce  desk  may  be 
introduced. 

While  many  beginners  may  not  plan  to  make  a  start  in  what  today 
is  considered  a  thoroughly  equipped  dental  office,  yet  sooner  or  later 


Automatic 
Switch 


Fig.  361. 


each  will  come  to  the  point  where  he  will  desire  to  so  equip  his  office 
and  he  will  find  many  labor  and  time  saving  devices  at  his  disposal. 

Electricity  admits  a  large  field  of  application,  used  as  it  is  in  the 
dental  engine,  lathe,  sterilizer,  annealer,  heaters  of  various  kinds, 
syringes,  both  air  and  water,  cauteries,  etc.,  to  say  nothing  of  the  light, 
illuminating  the  room  and  providing  by  low  power  lamps  for  oral,  and 
by  higher  power  for  antral  examinations. 


522 


THE    MANAGEMENT    OF    AN    OFFICE    PRACTICE, 


Compressed  air  is  another  most  useful  ally.  A  convenient  tank  of 
the  capacity  desired  may  be  placed  either  within  the  operating  room  or 
in  a  place  as  far  removed  as  the  operator  wishes.  This  tank  may  be 
filled  by  means  of  either  hand,  foot,  electric,  or  hydraulic  pump  (Fig. 
361).  The  latter  two  keep  the  pressure  at  the  full  capacity  of  the  tank 
— operating  automatically  as  the  air  is  used. 

The  uses  of  compressed  air  are  legion;  primarily,  with  the  air  syr- 
inge attached,  any  force — up  to  the  capacity  of  the  tank — may  be  reg- 
istered upon  the  dial,  giving  a  continuous  "chip-blower"  action.  If 
this  syringe  be  suppliedvvith  the  hot  air  electric  coil  attachment,  by  the 
turning  on  of  the  current,  regulated  to  any  degree  of  heat  desired,  the 
air  becomes  a  warm  blast. 


g-   t  in 


Above  cut  shows  its  application  to  the  hand-piece 

Fig.  362. — Engine  hand  piece — chip  blower. 

This  instrument  keeps  the  field  of  operation  free  from  debris,  permits  of  con- 
tinued operation,  thereby  shortening  the  time  at  least  50%.  It  also  minimizes 
the  pain  produced  by  the  heat  due  to  the  friction  of  the  burr  in  excavation. 

A  very  practical  compressed  air  syringe  attachment  is  manufactured 
by  L.  Green,  of  New  York,  N.  Y.  (Fig.  362).  It  was  first  introduced, 
as  far  as  the  writer  knows,  by  Dr.  C.  Edmund  Kells,  of  New  Orleans. 

It  consists  of  a  very  fine  silk  covered  rubber  tube,  leading  from  a  con- 
trolled outlet  to  an  atomizer  nozzle  attachable  to  the  engine  hand-piece. 
This  gives  a  direct  blast  of  air  upon  the  surface  requiring  operation, 
freeing  the  area  from  debris  of  cutting  and  acting  as  an  obtunder  by 
overcoming  the  heat  incident  to  the  friction  of  the  bur  in  cutting. 

Both  electricity  and  compressed  air  may  be  controlled  upon  one 
switch-board  (Fig.  363)  within  reach  of  the  operator's  hand  while 
standing  at  the  chair. 

In  choosing  an  instrument  cabinet  certain  things  should  be  con- 
sidered, whether  the  cabinet  be  an  inexpensive  or  a  costly  one;  com- 
pactness, adaptability  to  personal  needs,  and,  if  fitted  for  medicines, 


THE    MANAGEMENT    OF    AN    OFFICE    PRACTICE.  523 

that  there  should  be  provided  for  them  a  separate  compartment— one 
which  will  as  effectually  as  possible  prevent  any  odors  from  escaping. 
Many  practitioners  keep  medicaments  in  common  use  in  their  re- 


FiG.  363. 


spective  vials  under  a  glass  cover.  No  office  is  atttactive  if  permeated 
with  odors  of  any  kind  and  the  greatest  care  should  be  exercised  to  pre- 
vent their  presence. 


524 


THE    MANAGEMENT    OF    AN    OFFICE    PRACTICE. 


Running  water  is  essential  in  the  operating  room.  Fountain  cus- 
pidors may  be  obtained  in  great  variety,  suited  in  price  to  any  purse, 
and  offering  one  of  the  most  indispensable  aids  to  the  operator.  This 
may  be  stationary  or  attached  to  the  chair.  A  wash  basin  should  be  in 
plain  sight  that  the  patient  may  be  assured  that  the  operator  follows 
out  the  necessary  ablutions  before  each  operation. 

The  prosthetic  laboratory  should  be  within  easy  communication, 
but  sufficiently  removed  from  the  other  rooms  to  insure  freedom  from 


^ 


Addr 


Telephone 


Refe 


Home 
Business 

Home 

Business 


REMARKS. 


Fig.  364. 


odors  or  noise  reaching  them.     The  description  of  the  fitting  of  the 
laboratory  is  best  delegated  to  works  upon  prosthetic  dentistry. 

If  extraction  forms  a  part  of  one's  practice,  a  separate  room  should 
be  provided  for  the  specific  purpose,  fitted  with  the  necessary  chair, 
anesthetizing  apparatus,  cabinet,  running  water,  etc. 

RECEPTION  OF  PATIENTS. 

The  manner  of  the  reception  of  patients  should  be  given  careful 
consideration.  The  beginner  will  naturally  commence  his  operations 
upon  such  of  his  personal  friends  and  acquaintances  as  seek  his  care. 
These  in  turn  will  be  the  means  of  sending  others.  The  referring  of  a 
new  patient,  by  either  friend  or  fellow  practitioner,  should  always  be 
acknowledged  by  note  or  in  person. 

When  a  practice  has  assumed  normal  proportions,  a  systematic 
record  should  be  at  hand  to  give  the  necessary  data  regarding  each  pa- 


PERSONAL    TREATMENT    OF    PATIENTS.  525 

tient.  To  obtain  such  record  the  following  method  is  advised:  A 
new  patient  making  his  first  visit  is  confronted  with  the  following  card 
(Fig.  364)  which  is  filled  out  and  filed  in  a  cabinet  (or  drawer)  and 
the  reference  given  looked  up;  if  satisfactory,  much  is  gained  in 
establishing  cordial  relations  and  the  possibility  of  financial  loss 
greatly  diminished. 

PERSONAL  TREATMENT  OF  PATIENTS. 

The  success  of  an  operator  is  commensurate  with  his  ability  to  meas- 
ure up"  to  the  needs  of  those  who  require  his  services.  No  two  patients 
can  be  treated  ahke;  some  are  particularly  nervous  and  should  be  given 
every  assistance  in  their  endeavor  to  overcome  the  condition.  Help 
such  to  think  of  something  other  than  the  operation  itself.  Some  time 
is  well  spent  if  used  for  the  patient's  good  in  this  manner.  Allow  con- 
versation to  pass  to  a  congenial  channel,  while  progressing  as  rapidly 
as  possible  with  the  operation  required.  Much  more  can  be  done  up- 
on such  cases  with  this  procedure  than  could  otherwise  be  accom- 
plished. In  fact,  many  patients  will  voluntarily  offer  to  pay  for  extra 
time  and  labor  thus  spent  in  their  behalf  rather  than  endure  the  stress 
of  a  strenuous  sitting. 

On  the  other  hand  there  are  those  who  can  endure  any  operation 
with  little  or  no  ill  effect.  Upon  such  the  operator  may  proceed  with 
no  hesitation.  Patients  appreciate  cne  care  that  is  paid  their  in- 
dividual peculiarities.  There  is  no  surer  way  to  build  up  a  practice 
than  by  such  treatment  as  this,  added  to  sincere,  loyal  service  ren- 
dered and  honest  operations  performed. 

Children  should  receive  the  same  consideration  as  their  elders. 
Dr.  Ottolengui,  when  questioned  regarding  his  apparent  success  with 
children,  expressed  his  belief  that  it  was  due  to  the  fact  that  he  treated 
them  like  "grown  folks;"  and,  he  added,  the  longer  he  practiced  the 
more  he  treated  "grown  folks"  like  children. 

A  little  one  may  come  to  an  operator  for  the  first  time  with  no  pre- 
vious knowledge  of  or  dread  concerning  a  pending  operation.  The 
utmost  care  should  be  exercised  to  prolong  that  condition  of  mind.  Let 
a  child  once  acquire  a  dread  of  a  dental  visit  and  a  serious  handicap  is 
placed  upon  the  effective  service  of  the  operator — -a  handicap  which 
years  of  diplomacy  may  be  necessary  to  overcome.  If  a  child  re- 
ceives other  than  the  most  considerate  care  in  the  hands  of  an  operator 
he  has  only  himself  to  blame  for  much  unnecessary  trouble.  It  has 
been  most  wisely  said, ' '  Take  heed  lest  ye  offend  one  of  the  least  of  these 
little  ones."     The  young  practitioner  should  consider  that  these  are 


526  THE    MANAGEMENT    OF    AN    OFFICE    PRACTICE. 

the  ones  who,  if  treated  carefully  and  conscientiously,  are  to  be  the 
mainstay  of  his  later  practice,  and  the  ones  whose  operations  he  will 
look  back  upon  in  after  years  as  his  long  standing  successes. 

ASSISTANTS. 

The  subject  of  assistants  has  already  been  referred  to;  it  seems 
wise,  however,  to  lay  some  stress  upon  the  advantage  of  the  presence  of 
some  one — preferably  a  lady  assistant — at  the  chair  to  render  aid  to  the 
operator,  care  for  the  personal  comfort  of  the  patient  and  assist  in 
innumerable  ways  in  furthering  an  operation,  thus  saving  time  for 
both  operator  and  patient. 

Great  aid  is  found  in  having  such  an  assistant  trained  to  select 
and  handle  instruments;  provide  treatments;  prepare  cement  and  amal- 
gam fillings  ready  for  insertion  and  assist  in  the  operation  of  filling; 
understand  the  mechanism  and  control  of  the  electric  switch-board 
and  attend  to  it  if  desired  during  an  operation;  prepare  gold  for  filling 
purposes  and  assist  in  carrying  it  to  the  cavity  and  malleting  if  desired; 
manipulate  impression  material  preparatory  to  taking  impressions; 
care  for  the  cleaning  and  sterilizing  of  all  instruments  after  an  opera- 
tion and  note  their  return  to  their  proper  places.  To  these  duties 
some  add  the  making  of  inlays  and  kindred  matters. 

UTILIZATION  OF  TIME. 

The  important  assets  of  a  dental  practitioner  are  his  skill — the 
result  of  his  training  and  education — and  time.  To  misuse  either  is  to 
fail  to  attain  the  highest  possible  success. 

Primarily,  a  beginner  should  endeavor  to  fill  his  time  full.  Ar- 
range for  definite  hours  of  work  and  fill  those  hours;  if  not  occupied 
with  the  immediate  care  of  patients — for  all  will  not  be  blessed  with  an 
abundance  at  once — consume  the  time  either  in  experimental  work  upon 
lines  already  laid  down  in  college  or  in  study.  As  time  goes  by  less 
and  less  opportunity  will  present  itself  to  the  busy  practitioner  and  he 
looks  back  wath  regret  upon  time  wasted  when  it  might  have  been  used 
to  advantage.  Do  not  be  afraid  to  accept  work  even  if  the  most  mod- 
erate compensation  is  to  accrue.  Consider  early  practice  in  the  light 
of  valuable  post-graduate  experience  and  count  the  cost  of  apparent 
loss  as  chargeable  to  a  personal "  profit  and  loss  "  account.  Be  ready  to 
make  sacrifices  for  the  good  of  others  at  all  times,  but  especially  now 
when  time  is  not  of  such  value  as  it  will  be  later  in  practice.  Many 
young  practitioners  accept  infirmary  and  dispensary  positions  with 


UTILIZATION    OF    TIME.  527 

little  or  no  monetary  compensation  and  reap  golden  harvests  of  experi- 
ence. 

As  practice  increases  time  becomes  more  valuable  and  justly  should 
be  devoted  to  the  personal  clientele.     Here  comes  an  important  con- 


Telepmon  e 

ya 

Has  an  appointment  with 
"2>."2>.  5., 

A  V  E  N  U  E  , 


A   CHARQE   WILL    BE    MADE    FOR   ALLAPPOINTMENTS    BROKEN 
WITHOUT   TWENTY-FOUR    HOURS'   NOTICE. 


.^. _ 

A^cr^  cc?h  ^f/i/i.ext'n/rrve^ric. 

Ine cc/.. 

cc^^A    ^^^. 


IF  UNABLE  TO  KEEP  THIS  APPOINTMENT  PLEASE  GIVE  DUE  NOTICE, 

OTHERWISE  CHARGE  WILL  BE  MADE  FOR  THE  SAME. 

CONSULTATION   HOURS  FROM  4  TO  5  P.M. 


Fig.  365. — (Appointment  Cards.) 

sideration;  many  men  seem  to  feel  that  their  own  time  is  the  only 
thing  to  be  considered.  Just  as  much  importance  should  be  attached 
to  the  time  of  the  patient.  As  is  indicated  by  the  appointment  card 
(Fig.  365),  a  patient  is  given  an  appointment  for  a  definite  day  and 
hour;  that  hour  belongs  to  that  patient  and  should  be  as  nearly  as 


528  THE    MANAGEMENT    OF    AN    OFFICE    PRACTICE. 

possible  fulfilled  to  the  minute.  Habit  can  accomplish  much  in  pre- 
paring for  the  proper  arrangement  of  a  day's  work  so  that  the  various 
appointments  may  not  conflict  or  overlap  too  greatly.  Nothing  but 
a  serious  complication  is  a  sufficient  excuse  for  the  consuming  of  one 
patient's  hour  for  the  benefit  of  another.  It  is  just  that  a  broken 
appointment,  i.  e.,  one  broken  without  due  notice,  should  be  charged 
for,  and  it  is  equally  just  that  a  patient  should  receive  full  value  in  time 
for  an  appointment  set  and  without  delay.  There  are  occasions  when 
a  patient's  time  may  be  of  vastly  greater  commercial  value  than  the 
operator's  and  if  the  rule  of  charging  for  "broken  appointments"  were 
reversed  and  the  dentist  were  the  one  to  be  charged  for  unfulfilled 
obligations,  the  full  force  of  the  justice  of  this  statement  would  be 
acknowledged. 

EXAMINATION  RECORDS. 

Too  great  value  cannot  be  placed  upon  accurate  records  of  all 
operations  performed.  Three  forms  of  examination  cards  are  here 
given,  any  one  of  which  is  ample  for  the  requirement,  and  a  choice  of 
which  is  a  matter  of  individual  taste.     (Fig.  366,  Nos.  i,  2  and  3.) 

When  a  patient  first  presents  himself,  in  addition  to  the  reference 
card  already  mentioned  (Fig.  364),  the  results  of  the  oral  examination 
should  be  recorded  and  filed  in  proper  case  or  cabinet  in  alphabetical 
order.  This  card  may  be  kept  separate  from  record  cards  of  opera- 
tions performed,  or  used  as  both  examination  and  record  card  till  filled, 
when  a  second  card  for  the  same  patient,  marked  Number  2  on  its 
upper  left  hand  corner,  may  be  substituted  and  the  old  card  filed  away. 

Some  practitioners  dispose  of  old  cards,  but  it  is  a  wise  practice 
to  file  all  such  away  so  that  at  any  future  time  a  consecutive  history  of 
every  operation  performed  may  be  at  hand.  Many  times  these  records 
are  invaluable  for  legal  purposes  if  any  question  or  statement  should 
arise  demanding  enlightenment  or  verification.  Also,  much  value  has 
been  given  them  as  means  of  identification  of  those  who  have  lost  their 
lives  by  accident. 

DAILY  RECORDS. 

As  each  operation  is  performed  it  should  be  marked  upon  the  dia- 
gram and  either  by  sign  or  number  its  character  recorded  upon  that 
part  of  the  chart  assigned  for  such  record.  This  should  be  done 
immediately  to  avoid  error.  Some  practitioners  make  no  further 
daily  record  than  this;  others  prefer  to  add  a  record  upon  a  separate 
daily  record  card  (Fig.  367)  showing  all  operations  done  during  the  day, 
which,  when  transferred  to  the  proper  accounts,  may  be  filed  away 


DAILY   RECORDS. 
Examination  Blank  No.  i. 


529 


(Front) 


1 
1 

i 

i 

z 

C3 
05 

UJ 

'. 

. 

• 



' 

m 


Fig.  366. — (One  of  Three  Examination  Blank  Forms.) 


34 


53° 


THE    MANAGEMENT   OF    AN    OFFICE    PRACTICE. 
Examination  Blank  No.  2. 


r\ 


A  n  ,-■. 


7^ 


.-^^ 


® 


0     %flr 


Suggested  bv  S.  H.  Guilford,  A.  M.,  D.  D.  S., 


Examination  Blank  No.  3. 


Date 


■  190 


¥mmmm 


Examination  of  M 
teeth. 

Remarks: 


Fig.  366. — (Nos.  2  and  3  of  Examination  Blank  Forms.) 


DAILY   RECORDS. 


531 


190^ 


Month,. 


Day,. 


NAME.                 REMARKS. 

CHARGES. 

' 

Fig.  367. 


532  THE    MANAGEMENT    OF    AN    OFFICE    PRACTICE. 

among  a  collection  which  may  be  referred  to  at  any  time  for  informa- 
tion regarding  any  particular  day's  transactions.  Still  others  make 
a  record  in  a  daily  record  book.  As  each  patient's  operation  is  com- 
pleted the  time  consumed  is  marked,  operations  indicated,  etc.  The 
advantage  of  the  daily  record  book  is  that  it  gives  an  opportunity  to  in- 
sert every  important  event  of  the  day,  as,  for  instance,  the  visit  of  a 
patient  to  pay  a  bill  or  to  leave  an  important  message  which  should 
receive  prompt  attention  at  the  end  of  the  day's  duties.  A  portion  of  a 
page  of  such  a  record  may  include  items  as  follows: 

Monday,  December  17,  1906. 
8:30.     John  Jones. 

Root  treated     |  2 

I  Amalgam       |  8  D 
9:25.     William  Brown. 

Bill  paid  $18.00 
9:;^o.     Mrs.  N.  Smith. 

I  Gold  I  4j^-0. 

(Send  appoint,  to 

Miss  Smith  for  Jan'y.) 

Reference  to  various  teeth  should  be  made  by  numbers  as  indicated : 

Permanent  Upper 

8   I   7   I   6   I   5  j   4   I   3    I    2    I    I    I    I    I    2    i   3    i   4   I   5    I   6^L7   \  l_ 

8    1    7    I    6    !    5    I    4    I    3    I    H    n    H    n    3    I    4    I    5    I    6    t   7   T  8 

Lower 

Temporary  Upper 

V  IV    III     II    I    I    I     II     III     IV    V 

V  IV    III     Il"rj    I     II     III     IV    V 

Lower 

The  various  surfaces  should  be  affixed, 

CARD  SYSTEMS. 
All  these  record  cards  demand  system  and  today  little  in  the 
way  of  business  method  is  not  applicable  to  systematic  arrangement. 
That  systems  are  time  savers  is  an  undoubted  fact.  Such  being  the 
case,  there  is  no  excuse  for  their  non-adoption.  There  are  many 
laudable  systems  which  may  be  found  on  sale  at  the  various  dental 
depots.  One  system,  arranged  by  Dr.  Guilford,  of  Philadelphia 
(Fig.  368),  comprises  a  full  set  of  cards,  with  guide  cards  and  places 
arranged  for  the  tabulation  of  all  necessary  data  including  charges,  etc., 


CARD    SYSTEMS. 


533 


thus  doing  away  with  all  necessity  of  other  book-keeping.  This  feature 
appeals  to  many  while  others  prefer  to  have  no  record  of  charges  upon 
cards. 

The  cards  in  these  systems  are  usually  divided  into  three  sections 
each  arranged  alphabetically;  the  first  division  is  for  cards  of  patients 
whose  operations  are  incomplete;  second,  for  those  whose  operations 


Reduced  Illustration  of  Guilford's  Tin  Case  Outfit. 
Actual  size,  5  Inches  wide,  8'A  Inches  long,  7H  inches  high. 

The  accompanying  method  is  an  adaptation  of  the  Card  Index  System  to  the 
use  of  the  dentist.  It  takes  the  place  of  the  Ledger,  Cash-book  and  Bill-book 
all  of  these  accounts  being  kept  on  separate  cards  in  the  same  box  under 
suitable  headings. 


Fig.  368. 


have  been  completed  but  whose  bills  are  not  paid;  the  third  for  com- 
pleted cases  whose  accounts  are  closed. 

The  advantage  of  having  an  added  record  in  book  form  is  that  it 
gives  a  duplicate  in  case  a  card  should  be  mislaid  or  destroyed,  and  also 
affords  an  opportunity  to  have  at  a  glance  all  data  desired  for  long 
periods.  The  following  (Fig.  369)  is  a  page  from  a  loose  leaf  ledger 
which  is  an  admirable  example  of  what  concise  records  may  be.  This 
page  has  45  lines  upon  it,  but  the  number  may  be  made  whatever  is 


534 


THE    MANAGEMENT    OF    AN    OFFICE    PRACTICE. 


Remarks. 

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NOTIFICATION    OF    PATIENTS.  535 

desired.     If  books  are  kept  no  charges  need  be  displayed  upon  the 
cards  themselves. 

Another  excellent  system  is  that  of  having  a  set  of  envelopes  to 
be  filed  alphabetically.  These  are  intended  as  a  depository  for  inlays, 
crowns  or  dentures  ready  for  insertion  or  for  whatever  is  of  any  personal 
interest  or  value  connected  with  a  patient,  such  as  X-ray  skiagraphs, 
anomalous  teeth,  etc.  Whatever  is  deposited  within  the  envelope  is 
marked  upon  the  face  under  the  patient's  name  for  immediate  reference. 
In  this  day,  when  so  many  are  using  the  impression  method  of  preparing 
both  gold  and  porcelain  inlays,  this  system  commends  itself  as  the  re- 
sultant dies  may  be  filed  away  in  their  proper  envelopes,  and  duplicate 
inlays  may  be  made  at  a  moment's  notice,  if  required. 

NOTIFICATION  OF  PATIENTS. 

The  gratifying  increase  in  prophylactic  measures  in  dental  prac- 
tice today  makes  it  essential  that  a  distinct  supervision  of  the  patient's 
visits  should  be  maintained  by  the  attending  dentist.  To  regulate 
these  visits,  some  system  is  necessary  as  some  patients  require  more 
frequent  examinations  than  others.  There  are  some  practitioners 
who  expect  a  visit  from  their  patients  at  least  once  a  month.  The 
results  which  follow  such  a  course  are  wonderfully  satisfactory  in  pre- 
serving the  patient's  teeth.  Others  extend  the  time  to  two,  three  and 
six  months.  Few  patients,  if  any,  should  be  allowed  to  go  without 
examination  for  a  longer  period.  Several  plans  are  in  vogue  to  accom- 
plish the  supervision  sought.  A  simple  one  is  to  have  one  card  foi 
each  month  in  the  year  on  file.  When  a  patient's  operations  are  com- 
plete and  he  is  dismissed  his  name  is  placed  upon  the  month  card 
— one,  two  or  more  months  in  advance — with  the  date  and  time  of  day 
preferred.  Just  prior  to  the  first  of  every  month  the  next  month's  card 
is  taken  out  and  the  notification  cards  transmitted.     (Fig  370.) 

This  month's  card  then  becomes  "ancient  history"  and  the  next 
month's  card  takes  its  place  in  the  front  rank  to  be  taken  up  in  its  proper 
time.  The  old  card,  however,  may  be  kept  and  the  result  of  the 
notification  noted,  i.  e.,  if  the  appointment  is  kept  or  not,  and,  if  not, 
the  reason  given  for  its  rejection  or  postponement — opportunity  being 
then  given  for  a  change  of  date  with  no  break  in  the  continuity  of  pro- 
cedure by  oversight. 

A  very  excellent  plan  has  been  devised  by  Dr.  W.  A.  Cotton,  of 
New  York,  to  meet  these  several  card  requirements  upon  the  patient's 
original  record  card  (Fig.  371). 


536  TECE    MANAGEMENT   OF    AN    OFFICE    PRACTICE. 


FOR    AX     KXAMIXATIOIT. 

SllOCr.D      THIS      TIME      PHOVE      lNC;OXVEIf  lENT      TO      TOXJ, 
K1N1)1.Y  IN'FOHM  ME        AND  I        -Wllit,  MAKE  AXOTHER 

APPOINTMENT. 

VERY    TRULY     TOIIHS, 

,. D.D.  S. 

AVENTTE 


Tei-ephone.. 


(THIS    APPOINTMENT    IS    FOR    EXAMINATION    ONLY.) 

/^CP 

^/t. 

cue  /teg'  /y;  c/i/^i^Hm  t/.<itt  /ncct  ctt^e  natte  ctytA^e^n/ecc 

^^€ cc/—. <2  ci<i<:A^    <fc  €ixcc?nc^ie    i^<2(,/y)i  /ee^{ 

rrKi'Tti^d  A^x^aon^  ^/ct/idecc  dCT^^e  ^-otf x^  tccJc  ccc^/^ 

tlyn<iff/f:/  //kS   A  Hcne  crt€<i'nii€'rhce^^/ A^c^^c/tt/.  <xc^it^e  ttS  <z^ 

^J^»€^€4^t  <=^'^ 


Fig.  370. — (Notification  Cards.) 


FEES. 


537 


This  gives  the  months  upon  the  upper  margin  with  the  dates  iust 
underneath.  Two  Httle  clips  are  used,  one  solid  and  colored  red  to  be 
placed  upon  the  month  desired  for  the  next  appointment;  the  other  a 
cut  out  clip  to  show  the  day.  To  this  might  be  added  a  third  to  indicate 
a  special  hour  if  desired. 

That  the  practice  of  continuous  appointments  is  a  growing  one  is 
certain,  and  to  the  intelligent  public  it  is  a  great  blessing,  as  it  pro- 
vides constant  care  of  their  dental  welfare  with  no  personal  obligation 
to  remember  the  proper  periods  between  visits  and  an  assurance  that, 
barring  accidents,  their  teeth  will  be  kept  in  the  best  condition  and  in 
the  most  economical  manner. 


JAN.    FEB.    MAR.    APR.     MAY    JUNE    JU:_Y    AoG.    SEPT.    OCT.     NOV,    DEC. 
1     a     3     4     S     S     7     O     9     lO     11     I  2     13     1*     15     16     17     1a     19     20     21     22     23     ZA     25    26    27    2a    29    30    31 

NAME 

ADDRESS 

190               No         To  Services                          Dr.       H               Cr.                    Notifications 

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Fig.  371. — (Chart  of  teeth  upon  reverse  side.) 


FEES. 

The  subject  of  fees  is  a  difficult  one  to  discuss  from  any  stand- 
point and  especially  so  in  dealing,  as  is  the  intention  of  this  chapter, 
with  under-graduates  about  to  start  upon  their  professional  career.  I 
stated  at  the  opening  of  this  chapter  that  one  need  not  expect  to  grow 
wealthy  practising  dentistry.  Wealth,  however,  is  a  flexible  term 
and  I  must  leave  that  to  each  individual.  Charges  for  services  should  be 


538  THE    MANAGEMENT    OF    AN    OFFICE    PRACTICE. 

computed  upon  the  basis  of  several  considerations;  first,  "  How  much  is 
the  operation  as  I  have  performed  it  worth,  considering  all  things?" 
This  last  phrase  covers  much  ground.  The  beginner  does  not  expect 
to  value  his  time  as  highly  as  that  of  the  man  who  has  practised  for 
years,  nor  are  his  services  as  valuable  in  result — except  in  rare  cases — 
as  those  of  the  more  experienced.  Hence  the  fee  for  the  same  opera- 
tion by  one  man  need  not  necessarily  be  the  same  as  that  of  his  fellow 
practitioner. 

Environment  has  a  bearing  upon  fees;  a  man  in  a  small  village  with 
little  expense  can  afford  to  charge  less  than  his  confrere  in  costly  sur- 
roundings with  proportionate  increased  expenses  of  a  city  practice. 

Another  very  important  consideration  is  this:  "Can  this  patient 
afford  to  pay  my  usual  fee?"  Many  a  time  in  making  up  the  estimate 
of  the  value  of  an  operation  will  this  question  obtrude  itself  and  it  must 
be  met  conscientiously.  There  should  be  no  such  thing  as  a  fixed  and 
unalterable  price  for  an  operation.  There  are  some  who  will  need 
your  care;  give  it  cheerfully,  and,  whether  or  not  the  exact  remunera- 
tion in  dollars  and  cents  results,  the  satisfaction  of  duty  performed  will 
always  remain  with  you  and  the  successful  building  up  of  a  practice  will 
be  assured. 

The  basis  of  calculation  of  fees  differs  with  different  men.  Some 
charge  for  each  filling,  denture,  etc.,  rating  the  fee  according  to  the  size 
and  character  of  the  operation;  others  charge  a  certain  fee  for  an  hour's 
services,  not  considering  the  character  of  the  operation  performed. 
There  are  faults  in  each  system,  and  the  only  satisfactory  one  seems 
to  be  in  a  combination  of  both. 

That  some  operations,  while  taking  a  short  time,  may  be  exceed- 
ingly arduous  upon  the  operator  yet  extremely  valuable  to  the  patient 
is  an  accepted  fact;  and  the  question  arises  should  such  an  operation 
be  charged  for  upon  the  same  basis  as  one  which,  while  taking  con- 
siderable time,  is  neither  a  severe  task  for  the  operator,  nor  of  great 
value  per  se  to  the  patient. 

Then,  too,  some  operators  are  rapid  in  their  operations  and  ac- 
complish much  in  an  hour  of  thoroughly  satisfactory  work.  A  con- 
frere, with  the  same  conscientious  care  and  results  takes  twice  as  long. 
Should  they  receive  the  same  compensation? 

STATIONERY,  BILLS,  ETC. 

It  has  been  said  that  "we  are  judged  by  the  company  we  keep" 
and  a  professional  man  is  often  rated  by  the  stationery  he  uses.  This 
should  be  as  neat  and  unobtrusive  as  possible.     Anything  beyond  one's 


STATIONERY,    BILLS,    ETC. 


539 


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FiC    -(7  2 


540  THE    MANAGEMENT    OF    AN    OFFICE    PRACTICE. 

degree  and  address  is  unnecessary  upon  professional  cards  or  note-heads. 
The  addition  of  "Dental  Surgeon"  or  "Surgeon  Dentist,"  etc.,  is 
needless  except  as  a  covert  attempt  to  enhance  by  the  term  the  degree 
which  should  need  no  such  enhancement  to  sustain  its  professional 
dignity. 

The  rendering  of  bills  for  professional  services  may  be  accom- 
plished in  several  ways  to  advantage.  Upon  the  bottom  of  the  bill  a 
clause  is  placed  which  reads  "  Bills  rendered  upon  completion  of  opera- 
tions" (Fig.  ,372). 

This  may  be  a  rule  from  which  deviations  are  permissible.  Many 
prefer  to  render  statements  for  all  work  accomplished  during  a  month; 
others  at  the  end  of  two  months;  still  others  at  the  expiration  of  six 
months,  in  which  case  June  ist  and  December  ist  are  the  dates  pre- 
ferred. 

Questions  arise  from  time  to  time  regarding  the  best  manner  of 
rendering  a  bill;  should  such  be  itemized  or  not?  This  must  be  left  to 
the  practitioner  to  decide  for  himself. 

Some  prefer  to  enclose  with  the  bill,  for  the  exact  information 
of  the  patient,  a  chart  showing  just  what  has  been  done — practically  a 
duplicate  of  the  record  card — indicating  the  time  spent  upon  and  the 
charge  for  each  operation;  others  enclose  the  record  card  but  omit  the 
individual  item  charges;  others  omit  all  record  cards  (unless  requested 
for  them)  feeling  certain  that  their  patients  have  all  confidence  in  their 
honest  intentions  in  rendering  statements. 

When  bills  have  been  prepared  an  accurate  alphabetically  arranged 
list  should  be  made  with  the  amounts  affixed.  As  returns  are  received 
the  name  and  amount  should  be  erased  from  the  list  and  the  credit  re- 
corded in  its  proper  place.  When  subsequent  bills  are  required  to  be 
rendered,  delinquents  are  thus  easily  traced  and  duplicate  statements 
marked  as  such.  Failure  to  respond  by  a  client  places  one  in  the  posi- 
tion where  he  may  require  either  the  services  of  a  collector  or,  in  ex- 
tremis, a  lawyer  to  enforce  a  settlement. 

When  all  is  said  the  great  secret  of  the  management  of  a  success- 
ful office  practice  lies  in  the  spirit  of  the  well-known  lines: 

"To  thine  own  self  be  true, 
And  it  must  follow,  as  the  night  the  day, 
Thou  canst  not  then  be  false  to  any  man." 

Exact  of  yourself  the  highest  standards  of  attainment,  ideals  and 
culture.  Strive  to  live  up  to  these  standards  and  the  result  will  be 
in  other  hands  than  yours. 


CHAPTER  XXXII. 


THE  APPLICATION  OF  THE  ROENTGEN  RAY  TO 
DENTISTRY. 

BY  C.  EDMUND    KELLS,  D.  D.  S. 

As  several  text-books  have  been  written  that  are  devoted  exclusively 
to  dental  X-ray  work,  it  is  evident  that  the  writer  has  no  light  task  to 
curtail  the  information  upon  this  subject  which  should  be  laid  before 
the  student  into  one  single  chapter.  However  he  will  in  this  limited 
space  use  every  endeavor  to  acquaint  the  student  with  such  fundamental 
instructions  that  he  will  be  able  to  begin  such  work,  while  at  best  he  will 
find  he  must  work  his  own  way  out  of  the  difficulties  with  which  he  meets, 
no  matter  how  many  text-books  he  may  have  read.  It  becomes  simply 
a  case  of  perseverance,  as  it  is  in  fact  in  every  other  branch  of  dentistry. 

Nomenclature. — ^There  are  many  synonymous  terms  used  by  differ- 
ent X-ray  operators,  each  apparently  using  those  which  appeal  to  his 
fancy  so  the  student  may  make  his  selection  with  impunity. 


An  X-ray  picture  is  called: 
Roentgenogram 


An  X-ray  operator  is  called: 

Roentgenologist 

Radiologist 

Radiographer 

Skiologist 

Skiagrapher 


Roentgenograph 

Skiagram 

Skiagraph 

Radiogram 

Radiograph 

History. — ^In  1879  Dr.  Wm.  Crookes,  an  eminent  English  scientist 
gave  to  the  public  the  result  of  his  investigations  of  the  properties  of 
matter  in  high  vacua,  which  had  been  made 
in  what  was,  and  still  is  called,  the  Crookes' 
tube,  from  which  the  air  was  exhausted  to  the 
1/1,000,000  of  an  atmosphere  (Fig.  373). 

For  seventeen  years  these  tubes  were 
found  in  laboratories  throughout  the  world, 
and  scientist  and  student  were  charmed 
alike  with  the  study  of  the  cathode  ray 
within  the  tube,  but  their  usefulness  extended 
no  further. 

In   1896  Prof.   Wilhelm  Roentgen  of  Wiirzburg  sent  a  thrill  of 
surprise  and  incredulity  throughout  the  civilized  world  when  he  an- 

541 


Fig.  373. — The  Original 
Crookes'  Tube. 


542  APPLICATION   OF    THE   ROENTGEN   RAY   TO   DENTISTRY. 

nounced  that  however  interesting  to  the  student  were  the  features  pro- 
duced within  the  tube  by  the  cathode  ray,  of  vastly  more  wonder  and 
importance  were  the  effects  produced  beyond  the  confines  of  its  glass 
walls. 

Prof.  Roentgen  in  his  modesty  called  these  the  X-rays  (from  X  the 
unknown  quantity  in  algebra)  but  an  appreciative  world  has  given 
them  the  name  of  the  Roentgen  Ray,  the  term  X-ray  however  being 
used  for  brevity. 

While  the  X-rays  were  found  to  possess  the  power  to  penetrate 
substances  that  had  hith^to  been  opaque  to  any  rays  known  to  science, 
they  differ  from  ordinary  light  rays  in  that  they  pass  through  all  sub- 
stances in  straight  lines,  so  far  it  having  been  found  Impossible  to 
either  deflect,  reflect,  or  refract  them. 

Their  great  value,  however,  to  the  world  in  general  depends  upon 
their  power  to  penetrate  the  various  anatomical  elements  of  the  human 
body  in  different  degrees,  and  of  their  action  similar  to  that  of  light  rays 
upon  the  ordinary  photographic  plate  or  film. 

In  a  chapter  of  this  character,  space  being  limited,  it  is  impossible  to 
describe  all  of  the  various  kinds  of  apparatus  available  for  dental  X-ray 
work,  or  the  various  methods  pursued  by  different  operators,  but  it  be- 
comes necessary  to  confine  ourselves  to  the  applications  of  the  X-rays 
to  practical  dentistry  in  a  private  practice  as  done  by  the  writer  himself. 

It  is  assumed  that  the  ordinary  student  must  have  absorbed  by  his 
constant  contact  with,  and  observation  of  electrical  apparatus  in  use 
on  all  sides  to-day,  a  certain  amount  of  "kindergarten"  knowledge  con- 
cerning electricity  in  general.  He  must  know  that  the  "direct" 
and  "alternating"  currents  are  those  commercially  available  to  the 
general  consumer  of  Hght  and  power,  and  that  apparatus  in  general 
which  can  be  operated  by  the  one  are  not  suitable  to  the  other.  That 
storage  and  primary  batteries  are  available  for  a  limited  amount  of 
power  where  commercial  currents  cannot  be  had;  that  there  are  the 
Rhumkorff,  Tesla  and  Interrupterless  Coils,  all  available  for  X-ray 
work,  and  many  other  points  about  electricity  must  have  come  to  his 
knowledge. 

To  keep  abreast  of  the  times,  the  student  must  have  his  name  upon 
the  mailing  list  of  the  manufacturers  of  X-ray  apparatus,  and  read  their 
catalogs  and  other  literature  with  care. 

Dangers. — Early  X-ray  operators  could  not  naturally  be  aware  of  its 
gradual  deleterious  effects  upon  them,  and  not  until  after  constant  ex- 
posure, with  first  one  and  then  another  of  the  pioneers  manifesting  its 
symptoms,  were  such  discovered. 


APPLICATION   OF   THE   ROENTGEN  RAY   TO   DENTISTRY.  543 

While  it  was  soon  seen  that  prolonged  exposures  were  Hable  to  burn 
the  patient,  it  required  several  years  to  demonstrate  the  fact  that  con- 
tinued repeated  short  exposures  had  equally  as  disastrous  effects  upon 
the  operator. 

Although  the  writer  who  was  the  first  dentist  in  this  country  to 
install  an  X-ray  plant  in  his  office  and  do  regular  dental  work,  began  in 
1896  and  took  hundreds  of  pictures,  most  of  them  being  experimental 
work,  and  constantly  used  the  fluoroscope  with  his  bare  hands  it  was 
not  until  1903  that  any  ill  effects  were  produced  upon  them. 

From  the  fact  that  many  other  early  operators  lost  their  hands,  arms, 
and  some,  their  lives,  from  similar  exposures,  the  writer  must  owe  his 
fortunate  escape  to  his  being  comparatively  immune  to  the  Ray. 

After  seventeen  years  of  continuous  practice  with  the  X-ray,  the 
writer's  conclusions  are  that  it  is  even  now  impossible  to  foretell  the 
effect  of  the  X-ray  upon  a  subject.  Some  few  are  particularly  suscep- 
tible to  it. 

One  might  as  well  attempt  to  put  a  time  limit  upon  the  ability  of  a 
patient  to  remain  under  water  without  drowning,  as  to  place  such  a 
limit  upon  the  time  to  which  one  can  be  safely  exposed  to  the  X-ray. 

Just  as  some  people  will  be  very  seriously,  if  not  dangerously  affected 
by  the  ordinary  safe  dose  of  cocain,  so  will  some  people  be  affected  in 
very  rare  exceptions  by  an  ordinarily  safe  exposure  of  the  X-ray.  Two, 
three-second  exposures  in  one  instance  sufficed  to  produce  a  reddening 
of  the  face,  neck  and  shoulders.  In  another  case  two,  four-second  ex- 
posures caused  the  patient  a  very  uncomfortable  dermatitis  which 
appeared  to  be  best  relieved  by  the  application  of  olive  oil. 

In  the  course  of  time,  it  was  noticed  that  when  patients  were  burned, 
the  ill  effects  were  more  or  less  confined  to  the  areas  which  were  directly 
exposed,  and  that  the  surrounding  parts  that  were  covered  by  the  cloth- 
ing escaped  injury. 

Again  with  operators  who  were  constantly  using  the  fluoroscope, 
the  parts  covered  by  the  sleeves  were  protected,  while  the  parts  directly 
exposed  were  affected.  So  it  was  finally  discovered  that  the  highly 
penetrating  ("hard")  X-rays  themselves  did  not  produce  the  bad  effects, 
but  these  were  caused  by  rays  of  less  penetration  ("soft  rays")  also  pro- 
duced by  the  tube. 

As  a  result,  protecting  screens  or  filters  are  now  used  which  consist 
of  a  thin  layer  of  aluminum,  wood,  wool  or  leather  placed  between  the 
tube  and  patient.  These  substances  allow  the  free  passage  of  the  de- 
sirable X-rays  while  at  the  same  time  they  cut  off  the  harmful  rays 
emitted  from  the  tube. 


■f^ 


544  APPLICATION    OF   THE   ROENTGEN    RAY    TO    DENTISTRY. 

Tubes  are  also  enclosed  in  some  ray  proof  shield,  either  lead-glass 
or  opaque  rubber,  the  latter  not  being  absolutely  impervious,  but 
undoubtedly  sufficiently  so  when  used  in  conjunction  with  other  safe- 
guards. 

The  writer  uses  the  rubber  shield  shown  in  Fig.  374  with  which  is  seen 
three  diaphragms  furnished  with  it  through  which  the  rays  are  per- 
mitted to  pass.  Aluminum  screens  just  referred  to  are  placed  within 
these  diaphragms. 

Safety  of  the  Patient. — Believing  therefore  that  there  is  no  safe  limit 
to  set  upon  the  time  of  an  exposure  of  a  patient,  the  only  course  for  an 
operator  to  pursue  is  to  take  the  skiagraph  in  the  shortest  time  his  ap- 
paratus will  allow,  and  not  to  expose  the  same  patient  more  than  twice 
in  the  same  day.     If  with  high-powered  apparatus  (a  short  exposure) 

and  the  use  of  a  screen,  and  the 

^  tube  enclosed  in  an  impervious 

shield,  a  bad  result  should  follow, 

,.    -.  the  operator  would  know  it  was 

I  0\  due  to  an  unusual  idiosyncrasy 

O-—^'  i-.  J  in  the  patient,  and  through  no 

^P^^  ^H  ^^^^^  ^^  negligence  of  his  own. 

^H^P  ^^  Safet/y  of  the  Operator. — ^How- 

ever,   of   himself   the    operator 

must  be  vastly  more  careful.     In 
Fig.  374.  •' 

hospitals  and  other  places  where 
the  operator  is  taking  skiagraphs,  or  giving  treatment  hour  after  hour, 
it.'is  absolutely  necessary  for  him  to  stand  in  a  lead-lined  cabinet  or  in  an 
adjoining  room  with  a  lead-lined  intervening  wall,  from  which  he  sees 
his  patients  by  the  aid  of  mirrors. 

But  for  the  dental  operator  who  in  ordinary  practice  can  hardly 
average  a  case  or  two  per  day,  no  such  precautions  are  necessary. 
However  he  should  rarely  use  the  fluoroscope  as  a  means  of  entertain- 
ment for  his  friends  or  patients,  and  he  must  always  bear  in  mind  that 
the  less  he  exposes  his  person  to  the  ray,  the  better  it  will  be  for  him. 

Owing  to  some  of  the  peculiar  effects  of  the  ray  (other  than  pro- 
ducing burns  and  causing  of  the  falling  out  of  hair) ,  operators  who  have 
suffered  therefrom  are  not  prone  to  discuss  the  subject. 

In  the  early  days  it  was  noticed  that  X-ray  operators  began  to  be 
childless,  and  it  soon  became  a  well-established  fact  that  constant 
exposure  to  the  rays  resulted  in  sterility  in  the  male.  Whether  or  not 
his  result  is  produced  in  woman  is  not  so  assured,  but  the  writer's 
experience  inclines  to  the  belief  that  it  is  not. 


APPLICATION   OF    THE   ROENTGEN   RAY   TO   DENTISTRY.  545 

The  means  for  personal  safety  which  the  dental  operator  should 
adopt  are : 

1.  The  enclosure  of  the  tube  in  some  standard  ray  proof  cover. 

2.  The  operating  switch  should  be  at  least  four  feet  from  the  tube. 

3.  The  operator  should  stand  behind  a  one-sixteenth  inch  lead-lined 
screen  about  two  feet  wide  by  four  feet  high.  The  writer  does  not 
believe  that  in  dental  work  the  head  and  face  need  be  protected  when 
the  tube  is  enclosed. 

4.  He  should  always  use  protecting  gloves. 

To  test  the  value  of  these  precautions  in  his  own  individual  plant, 
and  which  he  should  do,  he  should  take  a  prepared  film,  wrap  a  piece 
of  brass  or  lead  wire  around  it,  and  hang  it  behind  the  lead  screen  for  a 
week  or  two  during  which  time  the  tube  must  have  been  run  upon 
several  occasions.  If  at  the  end  of  this  time  upon  developing  the  film, 
it  shows  no  trace  of  the  effects  of  the  ray  the  precautions  are  ample. 
But  if  on  the  contrary  the  film  has  been  affected,  then  the  precautions 
are  not  sufficient  and  the  covering  of  the  tube  must  be  made  more  safe, 
the  lead  on  screen  be  thickened,  or  both. 

The  Plant.  The  X-ray  Room. — ^The  writer  has  seen  coils  in  the 
operating  room,  and  also  in  the  reception  rooms  of  some  operators,  and 
the  film  developed  in  some  little  dark  closet  scarcely  two  by  four  feet  in 
size,  and  good  work  can  undoubtedly  be  done  in  this  manner,  but  the 
ideal  installation  calls  for  a  special  X-ray  room — (which  the  writer 
has)  an  inside  room  of  ample  size  to  accommodate  the  coil  and  all 
other  necessary  apparatus,  with  no  windows  and  only  one  door.  The 
walls  should  be  painted  preferably  red  and  here  all  the  apparatus  should 
be  kept  for  ready  use.  A  ceiling  lamp  of  ample  power  must  light  the 
room  brilliantly. 

This  being  an  inside  room  the  closing  of  the  one  door  cuts  out  all 
extraneous  light.  In  one  corner  is  a  sink  with  running  water,  in  front 
of  which  and  on  its  level  is  a  board  twelve  inches  wide  upon  which  all 
preparatory  work  is  done.  Above  the  sink  are  several  shelves  carrying 
all  the  necessary  photographic  chemicals,  developers,  etc.  The  sink 
is  set  two  feet  ten  inches  above  the  floor,  and  the  lower  shelf  is  eighteen 
inches  above  the  sink,  and  to  its  under  surface  is  secured  a  ruby  lamp 
which  throws  a  very  weak  light  down  upon  the  sink  and  working  board. 
A  white  lamp  is  also  attached  to  the  bottom  of  this  shelf  which  lights 
up  the  otherwise  dark  corner.  Above  this  shelf  and  in  its  center  is 
the  examining  box  shown  in  Fig.  392, 

Upon  the  side  wall  about  seven  feet  from  the  floor  projects  a  white 
lamp  lighting  up  the  shelves  (for  this  is  a  dark  corner)  and  below  this, 
35 


546 


APPLICATION    OF    THE    ROENTGEN    RAY    TO    DENTISTRY, 


and  just  within  reach  of  the  hand  is  a  second  ruby  lamp  which  hghts 
up  the  shelves  over  the  sink  that  their  contents  can  be  seen  "i«  the  dark.'" 
All  lamps  are  naturally  controlled  by  handy  switches. 

If  there  is  one  place  above  all  others  where  system  and  order  are 
needed,  it  is  in  a  dark  room,  for  what  is  required  there  must  be  picked 
out  almost  in  the  dark;  for  bear  in  mind  the  weaker  the  red  lights  the 
better  it  is  for  the  plates  and  films. 


Fig.  375. 


With  such  an  equipment,  X-ray  work  becomes  a  pleasure,  and  pic- 
tures can  be  taken  and  finished  ready  for  inspection  within  five  minutes, 
frequently  an  accomplishment  of  very  great  importance. 

Apparatus. — ^The  writer  once  wrote  an  article  on  the  "Uses  of  the 
X-ray  in  Dentistry"  when  so  rapid  were  the  improvements  being  made 
at  that  time,  both  in  apparatus  and  technique,  that  it  was  in  good 


APPLICATION    OF    THE    ROENTGEN   RAY    TO    DENTISTRY.  547 

part  out  of  date  before  it  came  off  the  press.  While  of  late  years  the 
changes  have  not  been  quite  so  rapid,  the  art  is  still  a  new  one,  and  this 
paper  may  possibly  share  the  same  fate. 

The  prospective  purchaser  of  an  X-ray  outfit  must  look  for  little  ad- 
vice relative  thereto  from  any  text-book,  but  must  study  the  latest  cata- 
logs of  reUable  manufacturers,  in  order  to  obtain  the  benefit  of  the  latest 
improvements. 

The  Coil. — ^An  X-ray  tube  cannot  be  operated  by  connecting  its 
terminals  to  the  wires  supplying  the  iio-volt  current.  When,  however, 
this  current  is  passed  through  the  primary  of  Ruhmkorf  induction  coil 
by  some  wonderful  process  of  nature  it  can  be  stepped  up  to  a  current 
of  many  thousand  volts,  while  also  by  another  inexorable  law  of  nature, 
the  amperage  is  correspondingly  decreased.  This  current  of  such 
tremendous  voltage,  but  of  practically  no  volume  is  the  kind  necessary 
for  the  tube;  therefore  the  object  of  the  coil  is  to  transform  the  unsuit- 
able street  current  into  one  suitable  for  the  operation  of  the  tube. 

While  there  are  much  more  powerful  apparatus  in  use  than  the 
writer's,  he  finds  his  twelve-inch  coil  equal  to  any  dental  requirement 
at  this  date  (Fig.  375). 

The  Interrupter. — ^However,  while  the  steady  flow  of  this  commercial 
current  through  an  ordinary  electric  lamp  or  electric  motor  will  operate 
it,  it  will  not  operate  an  induction  coil  if  connected  directly  thereto. 

The  flow  of  the  electric  current  must  be  stopped  and  started  at  a 
rapid  rate,  usually  the  more  rapidly  the  better,  in  order  to  run  an  in- 
duction coil.  To  obtain  this  result  an  interrupter  is  connected  in  the 
circuit,  and  this  may  be  either  a  vibrator,  a  mercury  turbine  or  an  elec- 
trolytic. For  our  purpose,  the  last  more  properly  called  the  '*  Wehneldt'* 
(the  name  of  the  inventor)  is  the  best,  as  it  gives  several  thousands  of 
makes  and  breaks  per  minute,  and  requires  but  little  attention  to 
maintain. 

This  consists  of  a  jar  containing  a  solution  of  sulphuric  acid  and 
water  of  a  density  of  1220  Baume  hydrometer,  into  which  depend  from 
the  cover  a  porcelain  sheath,  through  which  protrudes  a  platinum  wire 
the  point  of  which  being  exposed,  forms  one  electrode,  and  a  sheet  of 
lead  which  forms  the  other.  In  Fig.  376  is  shown  the  type  of 
interrupter  here  referred  to. 

The  more  the  platinum  wire  is  allowed  to  protrude  through  its 
porcelam  sheath,  the  less  resistance  there  will  be,  and  therefore  the 
greater  will  be  the  amperage  of  the  current  passing,  and  the  slower  will 
be  the  interruptions.  The  less  platinum  exposed,  the  less  current  will 
flow  and  the  interruptions  will  be  the  more  rapid. 


548         APPLICATION   OF   THE    ROENTGEN   RAY   TO    DENTISTRY. 


In  use  the  current  enters  through  the  platinum  electrode,  passes 
through  the  electrolyte  and  on  to  the  negative  lead.  However  hardly 
has  it  passed  through  the  acid,  than  a  chemical  change  takes  place.  A 
bubble  of  hydrogen  gas  collects  on  the  platinum  point,  the  flow  of  the 
current  is  stopped,  whereupon  the  bubble  bursts.  Instantly  the  flow 
of  the  current  recurs.  The  bubble  forms  again,  the  flow  stops,  the  bub- 
ble bursts  and  so  on.     All  this  occurs  with  inconceivable  rapidity. 


Fig.  376. 

The  first  Wehneldt  interrupters  were  made  as  just  described,  but 
later  they  were  made  with  two  or  more  platinum  points  to  allow  of  the 
passing  of  a  greater  volume  of  current,  but  as  the  writer's  original  one 
point  appliance  has  always  proven  satisfactory,  he  has  made  no  change. 

During  long  exposures,  this  interrupter  though  placed  in  a  water 
cooling  jar,  will  become  heated  and  fail  to  work,  but  owing  to  the  short 
exposures  needed  for  dental  work  we  are  not  subject  to  this  trouble. 
Should  the  coil  cease  working  without  any  apparent  cause  the  trouble 
may  be  a  large  bubble  of  gas  which  refuses  to  burst.  In  this  event 
rapidly  opening  and  closing  the  circuit  by  the  switch  for  a  few  times  may 
start  the  coil  again,  or  that  failing,  a  good  sudden  shake  of  the  jar  may 
relieve  the  trouble.  If  the  trouble  is  not  in  the  interrupter,  then  all 
connections  must  be  examined,  as  a  loose  wire  will  stop  its  operation,  or 
possibly  a  fuse  has  been  blown. 

The  Rheostat. — ^The  rheostat  is  an  appliance  for  regulating  the  quan- 


APPLICATION    OF    THE   ROENTGEN    RAY    TO    DENTISTRY.  549 

tity  (Amperes)  or  current  supplied  to  the  coil.  Usually  it  consists  of  an 
iron  plate,  carrying  upon  its  back  a  series  of  resistance  wires  imbedded 
in  enamel,  which  both  insulates  and  fire-proofs  them.  Upon  its  face  is 
a  pivoted  lever,  the  free  end  of  which  slides  successively  over  a  series 
of  contact  points,  each  of  which  cuts  in  (or  out)  a  certain  amount  of 
the  resistance  wires,  thus  allowing  more  or  less  current  to  flow  through 
the  line.  The  rheostat  should  be  furnished  with  the  coil  and  is  seen  on 
the  left  of  Fig.  375  otherwise  a  separate  rheostat  as  shown  in  Fig.  377 
can  be  used. 

Meters. — Meters  are  not  indispensable,  but  unless  they  are  used  the 
operator  can  never  know  just  where  he  stands  which  is  necessarily  rather 
unsatisfactory.     The  Ampere-meter  registers  the  quantity  of  current 


Fig.  377. 

taken  by  the  coil,  and  the  Milli-ampere  meter  that  passing  through  the 
tube.     These  are  shown  in  Fig.  375  with  the  coil. 

The  Switch. — ^There  is  nothing  unusual  about  the  switch  used  upon 
X-ray  apparatus,  it  being  of  the  usual  "jack  knife"  pattern  as  it  is 
called. 

Head  Rest. — ^Practically  all  dental  work  can  be  done  as  well  and  much 
more  expeditiously  with  the  patient  in  a  sitting  posture  as  in  the  prone, 
so  no  X-ray  table  is  necessary.  If  the  operator's  coil  is  in  one  of  his 
operating  rooms,  the  patient  may  be  seated  in  the  dental  chair  which 
furnishes  an  ideal  support  for  the  body  and  head.     But  if  a  special 


55©  APPLICATION    OF   THE    ROENTGEN   RAY   TO   DENTISTRY. 

X-ray  room  is  used,  then  an  ordinary  chair  with  a  portable  dental  head 
rest,  Fig.  379,  is  very  satisfactory.  A  cushion  should  be  at  hand  to 
place  on  the  seat  of  the  chair  for  small  children. 

Possibly  the  white  enamel  chair  used  by  nose  and  throat  spe- 
cialists might  appeal  to  some,  as  it  is  an  attractive  piece  of  furniture 
and  would  probably  answer  the  purpose  very  well. 

The  Fluoroscope. — ^Many  substances  possess  the  peculiar  property 
of  becoming  fluorescent  under  the  influence  of  the  X-ray,  and  advantage 
of  this  is  taken  in  the  construction  of  the  ordinary  fluoroscope  (Fig. 

378)- 

The  best  are  constructed  with  a  platinum-barium-cyanide  screen 
covered  upon  the  inner  surface  with  a  sheet  of  lead  glass  to  protect  the 


Fig.  378. 

eyes  and  face,  and  the  handle  is  guarded  by  heavy  lead  shield  to  protect 
the  hand.  Attempts  were  naturally  made  by  the  early  dental  operators 
to  adapt  this  instrument  to  dental  use  by  placing  a  piece  of  fluorescent 
screen  at  the  end  of  a  tube,  and  by  suitably  placed  mirrors  render  the 
shadow  of  a  tooth  visible,  and  in  other  forms,  but  a  practical  instrument 
of  the  kind  is  simply  impossible  in  the  present  state  of  the  art. 
•   The  ordinary  fluoroscope  is  of  little  value  to  the  dental  operator  for 


APPLICATION    OF    THE   ROENTGEN   RAY   TO    DENTISTRY.         551 

other  than  the  purpose  of  determining  the  efficiency  of  his  tube  for  which 
it  is  necessary. 

As  the  length  of  exposure  of  the  film  to  the  rays  for  the  purpose  of 
taking  a  skiagraph  depends  upon  the  condition  of  the  tube,  the  operator 
must  naturally  be  able  to  determine  this  condition  prior  to  taking  the 
skiagraph.  This  may  be  determined  in  two  ways.  The  one  by  testing 
the  tube  with  a  fiuoroscope,  and  the  other  by  noting  the  mil-amperes 
passing  through  the  tube  as  registered  by  the  meter. 

Originally  almost  all  operators  would  place  one  hand  in  front  of  the 
tube  and  look  at  it  through  the  fiuoroscope  which  was  a  very  rapid  and 
satisfactory  method,  for  the  condition  of  the  tube  can  thus  be  instantly 
detected.  But  no  sane  person  would  do  this  now,  for  numbers  of  opera- 
tors have  lost  their  hands,  arms  and  even  some  lives  have  been  sacrificed 
in  this  manner;  therefore  penetration  gauges  or  penetrameters  are  now 
used  for  this  purpose.  By  placing  a  penetrameter  between  the  tube  and 
the  fiuoroscope,  the  efficiency  of  the  tube  can  be  instantly  determined. 

Penetrameter. — ^While  there  are  a  number  of  penetration  gauges  now 
on  the  market,  all  of  the  early  operators  must  necessarily  have  devised 
their  own.  After  tests  innumerable,  and  years  of  experience  making 
various  devices  the  writer's  latest  penetrameter  consists  of  a  strip  of  brass 
No.  9  B.  &  S.  gauge  one  inch  wide  by  four  inches  long,  near  one  end  of 
which  is  wrapped  a  strip  of  ordinary  soft  solder.  After  many  experi- 
ments he  found  that  when  this  strip  of  solder  can  be  faintly  seen  through 
a  brass  sheet  of  this  thickness,  the  tube  is  just  right  for  his  rapid  work, 
and  if  on  the  test  it  proves  too  high  or  too  low  to  get  this  degree  of  pene- 
tration, the  vacuum  must  be  changed  accordingly. 

In  practical  work,  each  operator  must  set  up  a  standard  of  intensity 
of  his  own  best  suited  to  his  apparatus  and  technique. 

Each  new  tube  as  it  comes  from  the  factory  must  be  tested  before 
use,  and  if  it  does  not  conform  to  this  standard,  the  vacuum  must  be 
altered  until  it  does.  Once  adjusted  the  writer  uses  such  a  tube  usu- 
ally for  months  at  a  time  without  giving  it  any  attention. 

Protection  Screen. — ^For  testing  out  the  tube  with  this  penetrameter, 
the  following  protecting  screen  is  used.  A  sheet  of  one-sixteenth  lead 
eighteen  inches  square  is  backed  by  a  wire  bound  sheet  of  No.  24  gal- 
vanized iron  to  give  it  stability,  and  this  is  secured  to  a  suitable  upright 
standard.  A  window  four  inches  square  is  cut  through  the  screen  which 
is  used  when  examining  the  head  and  jaws  with  the  fiuoroscope  (Fig. 

379)- 

A  lead  shutter  is  provided  in  which  is  cut  a  hole  one  inch  square  and' 
when  this  is  hung  over  the  four-inch  window  the  aperture  is  thus  re- 


552 


APPLICATION    OF    THE    ROENTGEN   RAY   TO    DENTISTRY. 


duced  to  one  inch.  The  tube  to  be  tested  is  placed  just  three  inches 
from  the  screen  with  the  center  of  its  diaphragm  opposite  this  one-inch 
opening,  across  which  the  penetrameter  has  been  hung  by  a  bolt. 
The  tube  is  now  excited  when  by  observing  the  penetrameter  through 
the  fluoroscope  the  condition  of  the  tube  may  be  ascertained.  The 
fluoroscope  is  held  about  one  inch  from  the  penetrameter.  If  the  solder 
strip  is  distinctly  seen  through  the  brass,  the  tube  is  just  right  for  the 
writer's  technique;  if  not,  the  vacuum  is  either  too  high  or  too  low,  and 


Fig.  379. — A.  Exclusion  Tube.  Ai.  Wooden  disk.  B.  Focusing  point.  C.  Pro- 
tection screen.  D.  Lead  shutter  hanging  over  four-inch  opening.  E.  Penetrameter 
hanging  over  one-inch  opening.  F.  Strip  of  solder  center  of  one-inch  opening.  G. 
Ordinary  chair  with  portable  adjustable  head-rest.  (Note  head  rest  is  covered  with  a 
fresh  paper  napkin  held  on  by  rubber  band  near  each  end  for  each  patient.  H.  Elec- 
tric fan  for  drying  films.  I.  Swinging  arm  for  carrying  films  for  drying.  J.  Films 
held  by  clips  for  drying.  K.  White  sheet  used  as  back  ground  for  taking  flash-light 
picture.    L.  Wooden  support  to  which  end  of  tube  is  attached  by  a  cord. 

Note. — Owing  to  small  size  of  X-ray  room  a  good  photograph  was  impossible. 

must  be  changed  and  brought  to  the  standard.  If  that  is  impossible 
the  tube  is  returned  to  the  factory  for  readjustment. 

The  usual  penetrameters  on  the  market  have  several  different  gauges 
but  the  writer  prefers  the  one  as  described. 

It  will  be  noted  that  testing  a  tube  in  this  manner  is  done  in  absolute 


APPLICATION   OF   THE   ROENTGEN   RAY   TO   DENTISTRY. 


553 


safety,  as  all  rays  are  cut  off  from  the  operator.  Tubes  are  now  made  of 
such  good  quality,  that  the  writer  frequently  uses  one  for  months  with- 
out ever  testing  it  or  making  any  adjustments,  the  self-regulating  fea- 
ture keeping  it  always  at  standard  condition. 

In  every-day  practice  a  patient  is  brought  in  and  seated,  the  tube 
is  swung  into  position,  the  prepared  film  put  in  position,  the  circuit 
closed  for  from  one  to  three  seconds  according  to  the  density  of  the  parts 
(the  third  molar  only  requiring  the  maximum  of  three  seconds)  and  a 
satisfactory  result  is  usually  obtained. 

Intensifying  Screens. — An  intensifying  screen  consists  of  a  sheet  of 
card  board  covered  on  one  side  by  a  layer  of  the  finest  grains  of  plati- 
num-barium-cyanide. When  this  is  enclosed  with  a  film — the  granular 
side  in  contact  with  the  emulsion  surface — ^and  exposed  to  the  X-rays, 
the  screen  fluoresces  (as  described  under  the  fluoroscope)  and  so  greatly 
increases  the  action  of  the  rays  upon  the  emulsion,  that  the  length  of  the 
exposure  may  be  reduced  from  one-half  to  four-fifths  of  the  time  re- 
quired to  get  the  same  result  without  it. 

However,  while  this  has  the  advantage  of  cutting  down  the  time  of 
exposure,  it  has  the  more  than  compensating  disadvantage  of  destroy- 
ing the  detail,  and  as  dental  exposures  are  usually  sufficiently  rapid, 
the  writer  up  to  this  date  has  used  them  but  little  in  practice. 


Fig.  380, 


However,  as  each  operator  must  "try  out"  the  various  devices  for 
himself,  the  student  should  provide  himself  with  an  intensifying  screen — 
that  is  a  bit  of  it  about  one  and  one-fourth  by  one  and  one-half  inches 
— and  test  it  out,  and  then  decide  for  himself  whether  or  not  to  use  it. 

The  X-ray  Tube. — Immediately  upon  the  discovery  of  the  Roentgen 
Ray,  tube  makers  set  to  work  to  improve  upon  the  original  Crookes' 
tube  and  many  types  have  been  made.  The  self-regulating  tube  shown 
in  Fig.  380  might  be  called  the  standard  form  in  general  use  to-day  for 
skiagraphic  work. 

It  might  be  well  to  state  that  even  to-day  there  is  a  diflterence  of  opin- 


554  APPLICATION   OF   THE   ROENTGEN    RAY   TO    DENTISTRY. 


ion  among  manufacturers  as  to  exactly  what  transpires  within  an 
excited  tube,  but  all  users  of  tubes  know  that  with  use  its  vacuum  is 
raised.  While  it  is  exhausted  to  the  one  millionth  of  an  atmosphere 
there  must  still  be  some  air  within  the  tube,  and  this  is  supposed  to 
become  attached  to  the  walls  under  the  influence  of  the  electric  current. 
By  heating  the  tube  with  an  alcohol  lamp,  this  air  will  be  driven  off  and 
so  the  vacuum  lowered. 

But  this  is  an  unsatisfactory  process,  and  so  self-regulating  tubes 
are  made,  so  constructed  that  when  the  vacuum  within  the  tube  reaches 
a  certain  pre-determined  degree,  the  current  is  deflected  or  "shunted" 
through  the  regulating  chamber  and  on  to  the  other  terminal  of  the  tube. 
In  passing  through  this  chamber  which  contains  some  chemical,  it 
liberates  a  gas  which  at  once  lowers  the  vacuum.  The  moment  the 
vacuum  is  thus  lowered  sufficiently  to  allow  the  current  to  pass  through 
the  tube,  it  no  longer  passes  through  this  regulating  chamber,  the  lower- 
ing of  the  vacuum  ceases,  and  thus  a  nearly  constant  degree  of  vacuum 
is  automatically  maintained.  When  used  for  extended  exposures,  the 
operator  usually  opens  and  closes  the  circuit  at  intervals.  Suppose  he 
desires  a  thirty-second  exposure;  he  would  run  the  tube  say  ten  seconds, 

and  open  the  circuit  for  ten,  then 
close  for  ten  and  open  for  ten 
more,  and  then  give  the  final  ten 
seconds.  This  gives  the  tube  in- 
termittent rest,  serves  to  keep  it 
cool,  and  keeps  the  vacuum  more 
even. 

Experience  is  the  only  teacher 
of  all  the  vagaries  of  an  X-ray 
tube.  The  operator  distinguishes 
when  the  tube  is  too  low  by  the 
color  of  the  tube,  and  the  fact  that 
it  does  not  illuminate  his  fluoro- 
scope.  Likewise  when  the  vacuum  is  too  high,  the  clearly  defined 
hemisphere  is  lacking.  If  the  tube  is  punctured,  it  becomes  a  bluish 
color  or  sparks  will  jump  across  the  terminals  within  the  tube.  Such 
tubes  may  be  returned  to  the  maker  and  frequently  can  be  made  good. 
The  Inverse  Current. — ^While  the  main  current  traveling  through  a 
coil  is  in  one  direction,  there  is  at  times  a  very  slight  current  traveling  in 
the  opposite  direction,  called  the  "inverse"  current  which  may  occa- 
sionally manifest  itself  in  the  tube.  It  not  being  desirable  to  let  this 
current  through  the  tube,  it  may  be  prevented  by  separating  the  termi- 


FiG.  381.— Valve  Tube. 


APPLICATION    OF    THE    ROENTGEN   RAY    TO    DENTISTRY. 


555 


nals  at  the  coil  for  a  half  inch  or  so  over  which  gap  it  is  too  weak  to  jump 

(Fig-375)-_ 

A  "series  spark  gap"  and  a  "valve  tube"  (Fig,  381)  are  devices 

used  to  cut  out  the  inverse,  but  the  writer  has  not  found  them  necessary 

in  his  work,  and  relies  upon  the  gaps  at  the  terminals  (Fig.  375). 

The  following  is  taken  almost  verbatim  from  a  recent  circular  issued 
by  the  Scheidel- Western  X-ray  Coil  Co.  as  the  writer  cannot  improve 
upon  its  conciseness  or  value. 

Suggestions  for  Using  X-ray  Tubes.  Positive  and  Negative  Pole. — 
This  is  determined  by  the  action  of  the  spark  on  the  disc  connected  to 
the  poles.  If  the  sparks  appear  to  come  from  the  edge  of  the  disc,  the 
disc  is  positive  and  point  negative.  If  the  sparks  appear  to  come  from 
the  center  of  the  disc,  the  disc  is  negative  and  the  point  positive.  Do 
not  use  a  heavy  spark  or  flame  while  making  this  test.  (Reduce  the 
current  by  cutting  in  the  resistance  wires  in  the  Rheostat.)     (Fig.  382.) 


Positive.    Negative 


,  Fig.  382. 

To  Raise  the  Vacuum  of  the  Tube. — ^When  the  tube  is  warm  it  will 
generally  be  lower  in  vacuum  than  when  cold  (Fig.  383). 

Reverse  the  connections,  connecting  the  positive  pole  to  the  assist- 
ant anode  cap  "I"  and  the  negative  pole  to  anode  cap  "K"  first 
removing  the  connecting  wire  "H"  and  using  a  light  current  and  per- 
mitting it  to  pass  for  one  or  two  minutes. 

The  two  cords  connecting  "I"  and  "K"  to  your  coil  should  be  so 
arranged,  that  before  reaching  the  connections  on  the  tube  they  will 
be  closer  together  than  the  distance  between  any  part  of  the  glass 
surrounding  anode  "K"  and  the  assistant  anode  cap  "I"  or  there  will 
be  danger  of  sparks  jumping  from  assistant  anode  cap  "I"  through  glass 
to  anode.  After  operating  tube  with  a  light  current  in  this  manner  for  a 
short  time,  change  your  connections,  connecting  up  in  the  regular  way 
and  the  tube  will  be  found  to  have  a  higher  vacuum.  Repeat  the  opera- 
tion if  not  high  enough.  Be  careful  in  doing  this  not  to  raise  the  vac- 
uum too  high,  for  if  this  method  is  used  very  much,  it  has  a  tendency 
to  make  the  tubes  freaky.     Experience  is  the  only  teacher. 


556 


APPLICATION   OF   THE    ROENTGEN   RAY   TO    DENTISTRY. 


Cotmecting  X-ray  Tubes. — ^The  positive  pole  of  the  coil  is  connected 
to  the  anode  cap  "K"  and  the  negative  pole  to  the  cathode  cap  "L.'* 
The  current  passes  from  the  anode  "A"  to  the  cathode  "C"  and  is  re- 
flected back  as  the  invisible  cathode  stream  "M"  to  the  focal  point  "N" 
producing  the  X-ray  which  passes  through  the  walls  of  the  tube. 

Strength  of  Rays. — ^The  most  rapid  and  effective  rays  are  those  re- 
flected at  right  angles  from  the  cathode  stream  forming  a  focal  point  on 
the  anode  surface  and  shown  graphically  by  the  heavy  cone  "No.  lo." 
The  strength  of  the  rays  gradually  decreases  as  indicated  by  the  num- 
bers "8-6-4,"  etc. 


Fig.  383. — A.  Anode.  B.  Assistant  anode.  C.  Cathode.  D.  Regulating  cham- 
ber. F.  Regulating  adjuster.  G.  Hemisphere.  H.  Connection  wire.  I.  Assistant 
anode  cap.     K.  Anode  cap.     L.  Cathode  cap.    M.  Cathode  stream.    N.  Focal  point. 


Adjustment. — Before  passing  the  current  through  the  tube,  set  the 
regulating  adjuster  "F"  so  that  its  end  is  from  one  and  one-half  to  three 
inches  from  cathode  cap  "L,"  according  to  the  vacuum  desired. 
(For  the  writer's  high  penetration  work  he  sets  it  at  four  inches.) 

Visible  Hemisphere. — ^When  the  tube  is  correctly  connected  there 
should  be  a  distinctly  marked  hemisphere  of  green  fluorescence. 

Regulation. — ^If  sparks  pass  through  the  regulating  adjuster   "F'* 


APPLICATION   OF    THE    ROENTGEN   RAY    TO   DENTISTRY.  557 

and  the  cathode  cap  "L,"  it  means  the  vacuum  is  high.  If  too  high 
for  the  work  you  wish  to  do,  allow  the  sparks  to  continue,  reducing  the 
vacuum  until  the  right  degree  is  reached. 

When  the  vacuum  is  right,  raise  the  regulating  adjuster  until  the 
sparks  cease  to  pass.  Never  permit  the  regulating  adjuster  "F" 
to  touch  cathode  cap  "  L,"  as  so  many  sparks  would  pass  into  the  chem- 
icals in  the  regulating  chamber  "  D,"  and  so  much  gas  would  be  driven 
off  that  the  vacuum  would  be  destroyed  or  at  least  be  too  low  for  effect- 
ive work. 

Inverse. — ^At  times  in  addition  to  the  hemisphere  of  brilliant  green 
fluorescence,  there  will  be  bands  of  green  fluorescence  on  the  bulb  back 
of  the  anode,  as  shown  in  the  illustration  at  "P"  (Fig.  384)  and  parallel 
with  cathode.  This  indicates  either  that  the 
tube  is  of  low  vacuum  or  improper  adjust- 
ment of  the  machine  used  for  exciting  it. 
In  this  case  go  over  the  adjustment  of  your 
coil  or  raise  the  vacuum  of  your  tube.  If 
only  the  green  rings  show  and  there  is  no  Fig.  384. 

hemisphere,  it  indicates  that  the  tube  is 

incorrectly  connected  and  to  remedy  this,  reverse  your  connections. 
This  may  be  done  by  changing  the  wires  at  the  tube,  or  by  throwing 
over  the  reversing  switch  which  is  a  complement  of  coils." 

The  Third  Terminal. — Coils  are  now  furnished  with  a  third  terminal 
or  regulating  connection  upon  the  coil  itself.  This  has  the  advantage 
of  removing  the  heavy  spark  from  the  tube  which  sometimes  startles 
patients,  and  again  it  is  more  readily  manipulated  while  the  tube  is 
running  (Fig.  375). 

The  Tube  Stand  or  Carrier. — ^It  is  evident  that  the  X-ray  tube  must 
be  held  while  in  operation  in  some  kind  of  insulated  and  very  adjustable 
carrier.  There  are  many  "  tube  stands  "  on  the  market,  and  each  opera- 
tor must  select  the  one  which  appears  best  suited  to  his  requirements, 
and  later  on  he  probably  will  find  that  he  can  greatly  improve  the  one 
selected,  by  certain  modifications  which  occur  to  him. 

The  writer  has  made  many  tube  holders  each  an  improvement  upon 
its  predecessor  and  his  latest  pattern  swings  from  the  wall  which  is  very 
advantageous  from  many  points  of  view.  This  leaves  the  floor  clear, 
and  the  tube  may  be  instantly  swung  through  a  great  range.  It  is 
made  up  of  an  old  extension  engine  bracket  A,  some  parts  of  various 
tube  stands  B,  C,  and  E,  purchased  at  different  times  and  a  special  ball- 
and-socket  joint  D,  made  for  the  purpose.  With  its  very  great  range 
both  horizontal  and  vertical,  the  swinging  motion  of  the  arm  C  and  the 


558 


APPLICATION    OF   THE    ROENTGEN   RAY   TO   DENTISTRY. 


flexibility  given  the  clamp  E  by  the  ball-and-socket  joint  D.  this  appli- 
ance fully  meets  the  writer's  present  requirements  (Fig.  385). 

In  Fig.  379  is  shown  this  tube  holder  carrying  a  tube  and  its  pro- 


FlG.  385. 

tection  shield  and  fitted  with  one  of  the  writer's  exclusion  tubes  and 
focusing  point  which  will  be  described  later  on. 

Tube  Rack, — ^X-ray  tubes  being  more  or  less  fragile  and  quite  ex- 
pensive, must  be  handled  with  care,  and  when  not  in  use  suitable  pro- 


FlG.  386. 

vision  for  their  care  must  be  made.  Tube  racks  (Fig.  386)  can  be  pur- 
chased with  the  outfit  or  the  operator  may  knprovise  his  own.  The 
writer  keeps  one  tube  always  ready  for  use  on  the  tube  carrier,  a  second 


APPLICATION    OF    THE    ROENTGEN   RAY    TO    DENTISTRY.  559 

one  ready  at  hand  upon  an  improvised  rack,  while  the  reserve  stock  is 
kept  in  boxes  half  filled  with  excelsior,  out  of  the  dust,  and  thus  do  not 
require  handling. 

The  Compression  Diaphragm. — ^The  "compression  diaphragm"  used 
in  body  work  cannot  be  used  in  dental  work.  While  in  kidney  work  the 
body  may  be  "squeezed"  to  possibly  one-half  its  usual  thickness  by 
means  of  such  diaphragm,  there  are  no  tissues  about  the  head  that  will 
stand  squeezing. 

Exclusion  Tube. — ^In  the  early  days  when  it  required  from  five  to 
ten  minutes  for  the  taking  of  a  molar  skiagraph,  the  writer  devised  and 
tried  out  an  "exclusion  tube"  by  which  all  divergent  rays  were  cut  oflF. 
This  consisted  of  a  sheet  of  heavy  lead  about  fifteen  inches  square,  in 
the  center  of  which  was  a  three  inch  lead  tube  about  six  inches  long 
through  which  the  X-ray  must  pass. 

Thus  the  direct  rays  were  confined  to  this  small  area,  and  all  other 
rays  were  prevented  from  reaching  the  subject.  Undoubtedly  in  such 
long  exposures  this  was  an  advantage,  but  during  the  present  day  of 
snap  shots  it  is  doubtless  of  very  little,  if  any  value. 

When  the  X-ray  tube  is  not  covered,  it  is  a  very  easy  matter  to  focus 
it  upon  any  desired  point  as  one  can  look  through  it.  When,  however, 
it  is  covered,  and  a  small  diaphragm  used  at  very  close  range,  this  be- 
comes a  much  more  diflQcult  matter,  and  it  sometimes  happens  that  all 
that  is  desired  is  not  included  within  the  field,  owing  to  the  tube  not 
having  been  properly  focused.  For  this  purpose  then  the  "exclusion 
tube"  modified  to  suit  present  conditions,  and  fitted  with  a  focusing 
point  becomes  quite  valuable,  as  it  saves  time  and  insures  the  right 
spot  being  in  the  center  of  the  field. 

This  is  made  as  follows:  Select  the  diaphragm  which  comes  with 
the  rubber  tube  shield  in  which  there  is  a  two-inch  opening.  Obtain  a 
piece  of  brass  tubing  three  inches  long,  and  of  such  diameter  that  it  will 
just  fit  this  opening.  Solder  a  wire  (12  or  14  B.  &  S.)  bead  around  the 
outside  of  one  end  of  the  tubing.  Place  this  tube  through  the  dia- 
phragm with  the  beaded  end  toward  the  tube,  and  place  the  aluminum 
screen  in  place.  With  the  engine,  drill  four  holes  near  the  outside 
edge  of  this  diaphragm  equidistant  apart.  Pass  a  light  cord  through 
each  of  these  holes,  and  tie  it  in  position  on  the  tube,  being  sure  that 
it  is  centered  on  the  anode.  Provide  a  cylinder  of  wood  one-half  inch 
thick  that  will  just  slip  into  this  tube  and  stay  in  place  by  its  fit,  and 
through  its  center  drill  a  hole  with  a  No.  16  B.  &  S.  drill  and  run  a 
straight  piece  of  brass  wire  through  allowing  it  to  protrude  an  inch 
(Fig.  379)- 


560  APPLICATION    OF    THE   ROENTGEN   RAY   TO    DENTISTRY. 

When  posing  the  patient,  adjust  the  tube  so  that  this  pointer  is 
exactly  in  line  with  the  spot  marked  upon  the  face,  then  remove  the 
wooden  cylinder  and  take  the  picture. 

The  Film. — ^The  Roentgen  rays  would  be  of  comparatively  little 
value  were  it  not  for  the  fact  that  the  effects  produced  by  them  upon  the 
emulsion  of  the  ordinary  photographic  plate  are  the  same  as  those  pro- 
duced by  rays  of  light,  and  thus  skiagraphic  work  takes  one  into  the 
realms  of  photography,  an  already  well-developed  art.  Different  manu- 
facturers have  developed  special  emulsions  with  which  they  coat  their 
plates  and  films  for  X-ray  work,  these  products  being  as  a  rule  superior 
for  this  work  to  the  ordinan'  photographic  emulsions. 

Dental  films  are  supplied  for  use  ^nthin  the  mouth,  usually  cut  about 
one  and  one-fourth  by  one  and  one-half  inches,  and  placed  two  in  a 
packet  (emulsion  surfaces  in  contact)  and  wrapped  in  black  paper. 
The  writer,  however,  does  not  use  these,  as  he  prefers  to  obtain  his 
films  in  four  by  five-inch  sheets,  and  cut  them  to  fit  the  case  in  hand, 
enclosing  them  in  black  rubber  which  renders  them  both  light  and 
moisture  proof,  and  incidentally  makes  a  ver}'  flexible  packet,  allowing 
it  to  conform  to  the  arch,  and  there  are  no  sharp  comers  to  hurt  the 
patient. 

Akron  black  dental  rubber  Xo.  14  is  quite  satisfactor}'  for  this  pur- 
pose, as  it  comes  in  ven'  thin  sheets,  and  of  such  a  size  as  to  cause  no 
waste,  and  being  ven.'  stichy  is  readily  sealed  around  the  margins  by 
the  pliers. 

This  matter  of  wrapping  films  is  just "  up  to  "  the  individual  operator. 
If  he  can  take  the  prepared  dental  films  as  they  come  in  black  paper,  and 
have  the  patient  hold  them  in  place,  and  obtain  satisfactor>'  results, 
that  is  his  course  to  pursue.  If  he  cannot  get  the  desired  results  in  this 
manner,  then  let  him  try  the  methods  used  by  the  writer. 

About  all  the  special  films,  of  which  he  has  heard  prepared  for  den- 
tal work  have  been  tested  and,  he  has  finally  adopted  for  general  use 
the  Regular  Cine  Positive  Film  made  by  the  Eastman  Kodak  Co. 

^Vhile  this  is  not  as  rapid  as  many  other  films,  it  has  the  advantage 
of  being  thin  and  flexible,  develops  up  quite  rapidly,  and  fixes  out  ex- 
ceedingly quickly,  all  of  which  are  very  material  advantages  in  his 
method  of  work. 

Films  must  be  kept  in  lead-lined  boxes  when  near  the  tube  for  their 
protection  from  the  rays.  The  student  can  make  up  these  boxes  from 
one-sixteenth-inch  sheet  lead  for  small  sizes,  and  line  a  suitable  cigar 
box  (wide  and  flat)  with  the  same  for  a  larger  one. 

For  taking  skiagraphs  of  the  head  or  face,  with  the  plate  or  films 


APPLICATION    OF    THE    ROENTGEN   RAY    TO    DENTISTRY.  561 

outside  of  the  mouth,  undoubtedly  special  X-ray  emulsions  are  more  suit- 
able. A  film  or  plate  may  be  held  in  place  by  adhesive  strips  or  ban- 
dages during  long  exposures,  but  m  rapid  work  the  patient  or  an  assist- 
ant can  hold  it. 

Film  Holders. — While  the  patient  invariably  holds  the  films  for  all 
upper  skiagraphs,  the  writer  is  never  satisfied  to  have  tlie  patient  hold 
it  for  lower  teeth.  There  is  too  much  uncertaint}'  about  having  it  held 
immovably,  and  too  many  pictures  were  spoiled  by  not  getting  in  the 
required  region.  So  he  now  always  makes  a  film  holder  for  each  sepa- 
rate case.  The  three  minutes  spent  in  the  work  is  a  good  investment 
of  time,  as  with  such  a  holder,  the  desired  region  is  always  in  the  field. 

This  technique  is  as  follows:  The  patient  is  placed  in  the  dental 
chair,  and  a  piece  of  Xo.  28  aluminum  plate  is  cut  to  suit  the  case.  If  it 
is  a  molar  or  bicuspid,  it  can  be  longer  than  for  a  cuspid  or  incisor.  A 
row  of  sUts  one-fourth  inch  deep  are  cut  along  one  edge  with  a  pair 
of  scissors.  These  are  then  bent  over  in  an  uneven  row,  nearly  to  a 
right  angle.  If  it  is  a  molar  to  be  skiagraphed,  the  aluminum  is  left 
flat.     For  the  other  teeth  it  is  bent  to  conform  to  the  shape  of  the  arch. 

A  small  piece  of  modeling  compound  is  softened  by  diy  heat  and 
attached  to  the  row  of  lugs  of  aluminum  (p^e^'iously  warmed)  and  then 
placed  in  the  mouth,  and  while  the  aluminum  is  held  firmly  against  the 
arch,  the  modeling  compound  is  worked  over  the  crowns  of  the  teeth, 
and  at  the  last  moment  the  patient  closes  gently  upon  it.  Care  must  be 
taken  that  when  the  patient  does  close  down,  that  the  aluminum  is  not 
forced  away  from  contact  with  the  arch.  If  that  has  happened,  it  can 
be  readily  pushed  back  to  place.  This  fixture  is  then  removed  and 
chilled  by  a  blast  of  cold  air  or  under  the  tap  and  then  dried.  With 
a  little  experience  these  holders  are  quickly  and  easily  made. 

The  prepared  film  encased  in  rubber  is  now  attached  to  this  alu- 
minum plate  by  two  clamps,  made  of  strips  about  three-fourths  by 
one-eighth  inch  of  aluminum  plate  (same  gauge)  bent  upon  them- 
selves and  closed  on  to  the  film  holder  and  film  by  pliers.  Or  the 
original  piece  of  aluminum  may  be  cut  a  little  longer  than  otherwise 
necessar}',  and  slotted  at  each  end,  and  the  ends  bent  over  on  to  the 
film  packet  (Fig.  387). 

It  is  possible  for  a  patient  to  present  with  inflammation  about  a 
lower  third  molar  erupted  or  unerupted,  and  who  is  unable  to  open  the 
mouth  to  any  appreciable  extent,  and  therefore  it  is  impossible  to  follow 
the  usual  course  to  obtain  a  skiagraph  of  this  molar.  For  such  cases 
the  following  method  was  devised.  A  piece  of  aluminum  plate  X'o.  28 
gauge  was  cut  as  shown  at  A,  Fig.  388. 
36 


562 


APPLICATION   OF   THE   ROENTGEN   RAY   TO   DENTISTRY. 


Along  the  line  BC  the  plate  was  bent  upon  itself,  and  again  it 
was  doubled  upon  itself  at  DE,  the  end  B  being  clamped  in  place 
by  a  strip  of  same  material  at  GF.  Along  the  line  IH,  it  was  again 
doubled,  making  a  U-like  holder  for  holding  the  film.     The  corners 


Fig.  387. 

were  then  rounded,  a  film  placed  in  position  when  the  completed  and 
loaded  appliance  was,  as  shown  at  J.  K  shows  a  strip  of  aluminum 
from  which  the  clamps  are  cut. 


Fig.  388. 

The  film  can  thus  be  placed  in  the  mouth  fiatwise,  though  the  teeth 
can  only  be  opened  one-quarter  of  an  inch,  and  when  once  inside  by 
careful  manipulation  it  can  be  gradually  worked  into  place  back  of 
the  recalcitrant  third  molar,  and  held  there  while  it  is  skiagraphed 


APPLICATION    OF    THE    ROENTGEN   RAY   TO    DENTISTRY. 


563 


In  Fig.  389  is  shown  a  model  of  a  case,  and  the  skiagraph  of  its 
unerupted  third  molar  taken  by  the  aid  of  such  a  film  holder,  while 
the  front  teeth  were  separated  only  one-quarter  of  an  inch. 

Naturally  this  film  holdei  is  also  adapted  to  the  holding  of  films 
when  the  mouth  can  be  opened  normally,  but  the  writer  prefers,  as 
a  rule,  the  modeling  compound-aluminun  combination  which  requires 
no  holding  by  the  hand,  and  insures  the  film  being  always  exactly 
where  needed. 


Fig.  3S9. 

Care  of  the  Films. — Upon  receiving  a  new  lot  of  films  from  the  fac- 
tory, the  outside  envelope  is  dated;  it  is  taken  into  the  dark  room  and 
opened,  care  being  taken  to  keep  out  of  the  direct  rays  of  the  ruby  lamps, 
and  in  as  near  total  darkness  as  it  is  possible  to  work.  Two  sheets 
are  removed  and  placed  in  a  lead  box  provided  for  them  which  is 
immediately  covered,  and  the  balance  are  replaced  in  their  envelopes, 
put  in  a  small  iron  box  (an  ordinary  bank  box  to  be  purchased  at  any 
stationer's  is  most  suitable)  and  a  heavy  rubber  band  put  around  it 
to  keep  it  closed,  and  immediately  taken  into  another  room,  and  put  in 
some  safe  place. 

Preparation  Board. — This  is  a  piece  of  board  about  ten  by  twenty- 
four  inches,  one-half  of  one  side  of  which  is  covered  with  ordinary 
white  oil  cloth,  and  the  other  half  covered  with  black  oil  cloth,  which 
furnish  readily  cleanable  surfaces  upon  which  to  prepare  our  films. 


564  APPLICATION   OF   THE   ROENTGEN    RAY   TO   DENTISTRY. 

All  white  objects  are  to  be  placed  upon  the  black  end,  and  dark  ob- 
jects such  as  black  rubber,  etc.,  are  placed  upon  the  white,  and  any- 
thing can  thus  be  plainly  seen  under  the  faint  ruby  light. 

Enclosing  Films. — ^The  lead  box  with  its  films,  a  pair  of  scissors, 
and  a  pair  of  flat  pliers  are  placed  upon  our  preparation  board.  From 
the  box  of  Akron  black  dental  rubber  No.  14,  we  remove  several 
sheets  and  cut  them  crosswise  into  three  equal  parts.  The  linen  is 
then  removed  from  just  as  many  pieces  of  rubber  as  we  have  films  to 
enclose,  and  the  rest  are  put  back  into  the  box.  Those  needed  for 
immediate  use  are  laid  in  a  row  upon  our  white  oil  cloth  against  which 
they  will  show  up  in  sharp  contrast  in  the  feeble  ruby  light.  A  pattern, 
one  and  one-quarter  inches  by  one  and  one-half  inches  of  black  paper 
is  laid  beside  the  rubber.  Now  the  white  light  is  shut  off  and  the  red 
lamps  turned  on. 

The  lead  box  containing  the  films  should  be  out  of  the  direct  rays 
of  the  ruby  lamps — the  less  light  upon  it  the  better — ^and  should 
always  be  kept  closed.  Taking  from  it  the  two,  four  by  five-inch  sheets, 
and  examining  them  by  the  ruby  light,  one  sees  that  while  one  side 
is  very  glossy,  the  other  side  is  somewhat  "dead."  The  latter  is  the 
emulsion  side,  and  should  be  touched  as  little  as  possible,  for  finger 
marks  on  them  might  show.  These  sheets  are  placed  together,  emul- 
sion surfaces  in  contact,  when  by  the  aid  of  the  black  paper  pattern, 
three  strips,  each  one  and  one-quarter  inches  wide  by  five  inches  long, 
are  cut  from  them.  Again  laying  the  black  paper  pattern  upon  these 
strips,  from  each  are  cut  three  films  each  one  and  one-half  inches 
long.  Thus  eighteen  films  of  the  standard  size  are  cut  from  the  two 
sheets. 

The  object  of  having  the  pattern  black  is  that  it  can  be  readily 
seen  against  the  white  film.  The  film  being  four  by  five  inches,  if  the 
pattern  is  laid  upon  it  in  the  right  way,  it  will  be  cut  into  nine  one  and 
one-quarter  by  one  and  one-half  inch  films,  with  but  little  waste. 
If  the  pattern  is  put  on  virrong,  it  will  only  cut  six  films  and  the  balance 
will  be  wasted.  These  cut  films  are  put  in  a  small  pasteboard  box 
without  a  cover,  which  in  turn  is  placed  in  the  lead  box  and  covered. 

Film  Cutter. — In  place  of  the  black  paper  pattern,  a  regular  film 
cutter  as  supplied  by  any  photographic  supply  house  shown  in  Fig. 
392  may  be  used.  With  this,  films  may  be  cut  to  any  sizes  desired, 
and  it  is  a  very  convenient  device. 

Taking  two  of  these  cut  films,  and  putting  their  emulsion  or  film 
surfaces  together,  they  are  carefully  laid  on  one  end  of  a  piece  of  black 
rubber,  so  that  the  latter  overlaps  them  a  very  little  on  the  three  sides 


APPLICATION    OF    THE    ROENTGEN   RAY    TO   DENTISTRY. 


565 


(Fig.  390A).  The  free  end  of  the  rubber  is  carefully  doubled  over 
the  films,  and  the  edges  of  the  rubber  pinched  together  all  around  by 
the  pUers  (Fig.  390B). 

Film  Packet. — The  packet  is  then  held  close  to  the  lamp,  the  ragged 
edges  of  the  rubber  trimmed  ofif  (Fig.  390C)  (the  outline  of  the  film 
being  visible  through  the  rubber)  and  very  carefully  examined  to  see  if 
the  edges  are  safe,  for  if  at  any  spot  the  rubber  is  not  well  sealed, 
the  film  will  be  "light  struck"  and  ruined.  One  of  the  pieces  of  linen 
with  which  the  rubber  sheets  were  separated,  is  then  doubled  over  it 
and  it  is  put  in  one  of  the  little  lead  boxes  until  the  instant  for  use. 


Fig.  390. 


The  white  light  is  now  turned  on,  ruby  lamps  extinguished,  every- 
thing put  back  in  place,  and  the  preparation  board  also  put  away,  for 
this  is  only  used  when  preparing  films. 

Testing  out  the  Plant.— 'Let  us  now  assume  that  our  outfit  has  been 
race  ved,  and  we  are  ready  to  set  it  up  and  test  it  out.  A  place  for  each 
and  every  appliance  is  selected,  and  each  is  always  to  be  put  back  in 
place  that  it  may  be  readily  found  when  wanted.  The  coil  is  placed  in 
position,  the  no  D.  C.  electric  light  wires  having  been  previously  led 


566  APPLICATION    OF   THE   ROENTGEN   RAY    TO   DENTISTRY. 

to  a  convenient  outlet,  and  provided  with  fuses  vi^ith  a  carrying  capacity 
of  at  least  ten  amperes  more  than  the  maximum  our  coil  will  take. 

The  electrolytic  interrupter  is  next  filled  to  the  marked  line  with 
acidulated  water  of  the  proper  density  (a  Baumd  hydrometer  being 
used)  and  the  platinum  point  turned  up  so  that  it  barely  protrudes 
from  its  sheath.  This  interrupter  may  be  placed  in  another  room  if 
found  necessary,  though  it  is  most  desirable  to  have  it  at  hand. 

The  electric  wires  are  then  connected  to  their  proper  terminals 
according  to  the  instructions  accompanying  the  coil.  The  handle  of 
the  rheostat  is  then  placed  about  midway  between  the  terminals,  the 
disk  and  point  of  the  coil  are  placed  about  six  inches  apart,  and  the 
switch  closed.  If  the  spark  is  seen  to  jump  from  the  edge  of  the  disk 
to  the  point,  the  connections  are  right,  but  if  from  the  point  to  the  center 
of  the  disk,  they  are  wrong,  and  the  wires  must  be  reversed  where  they 
are  attached  to  the  coil. 

The  terminals  on  the  coil  are  next  separated  the  full  distance,  the 
rheostat  handle  placed  so  that  it  cuts  out  all  of  the  resistance,  and  the 
switch  closed.  If  the  current  jumping  across  the  terminals  is  a  good 
fat  fuzzy  flame,  looking  somewhat  like  a  caterpillar,  fast  work  is 
assured.     If  it  is  a  thin  blue  streak,  the  reverse  must  be  expected. 

This  weak  spark,  however,  may  be  caused  by  faulty  adjustment  of 
the  platinum  point  in  the  interrupter,  which  should  therefore  be  turned 
down  so  as  to  allow  the  passage  of  more  current. 

If  upon  throwing  on  the  full  current,  a  spark  jumps  across  the 
terminals,  and  then  all  is  dead,  it  probably  means  a  fuse  is  blown. 
Heavier  fuses,  or  lessening  the  exposure  of  the  platinum  point  in  the 
interrupter  will  overcome  this  diflSculty.  The  operator  must  keep  on 
hand  some  extra  fuses  for  instant  use  in  case  of  emergency. 

The  maximum  spark  of  which  the  coil  is  safely  capable  is  gotten 
by  carefully  adjusting  the  platinum  point.  Current  should  never  be 
left  on  the  coil  any  longer  than  necessary,  or  it  may  be  injured. 

With  the  coil  working  satisfactorily,  the  next  step  is  to  test  the  tube. 
This  is  carefully  clamped  on  the  tube  carrier,  swung  into  position  as 
nearly  at  right  angles  to  the  coil  as  possible,  the  wires  attached  to  its 
terminals,  the  rheostat  handle  set  about  in  the  center,  and  the  switch 
closed.  If  it  lights  up  as  shown  in  Fig,  380,  it  is  properly  connected;  if 
as  in  Fig.  384,  it  is  not,  and  the  reversing  switch  upon  the  coil  should  be 
quickly  thrown  over. 

The  current  should  never  be  put  through  a  tube  unnecessarily.  It 
uses  up  the  tube,  changes  its  vacuum,  and  a  puncture  might  result.  If 
for  any  reason,  it  is  advisable  to  run  it,  the  current  used  should  be  re- 


APPLICATION    OF    THE    ROENTGEN    RAY   TO    DENTISTRY.  567 

duced  by  rheostat.  The  maximum  current  should  only  be  put  through 
it  when  absolutely  necessary,  as  for  instance  when  testing  it  with  the 
penetrameter,  or  doing  actual  work. 

With  the  coil  and  tube  in  good  working  order,  the  next  step  is  to 
test  the  tube  according  to  instructions  given  with  the  penetrameter, 
and  with  the  efficiency  of  our  tube  assured,  we  are  now  ready  to  take 
a  skiagraph. 

For  our  first  experimental  picture,  it  is  well  to  take  an  assistant,  and 
try  the  upper  incisors  as  the  posing  for  these  will  now  be  described. 

Posing  the  Patient. — ^The  correct  angle  at  which  to  place  the  tube 
for  skiagraphs  of  the  upper  teeth  cannot  well  be  taught  by  the  corre- 
spondence method,  there  being  so  many  factors  to  be  considered. 
Upon  the  position  of  a  tooth  in  the  arch,  and  the  height  and  shape  of 
the  vault  which  varies  in  each  individual  must  be  based  the  position 
of  the  tube,  and  only  experience  can  teach  the  process. 

The  writer  believes  that  Dr.  Weston  A.  Price  was  the  first  to 
publish  diagrammatic  instructions  in  this  regard,  and  with  his  kind 
permission  they  are  now  given  as  they  can  hardly  be  improved  upon. 
He  says,  "Much  skill  is  required  to  place  the  film  and  tube  in  the 
proper  relations  to  the  teeth  to  produce  a  correct  shadow  of  the  parts 
without  distortion.  We  all  know  how  seldom  our  own  shadows  repre- 
sent our  true  height  or  shape,  because  the  source  of  the  light  and  the 
surface  receiving  the  shadow  are  not  in  the  proper  relation  to  the  object 
casting  the  shadow.  Each  of  these  three  factors  must  be  in  correct 
relation  to  the  other  two,  but  one  of  them,  the  teeth  and  surrounding 
structure  casting  the  shadow  are  by  their  peculiar  position  practically 
fixed  and  the  others  must  therefore  be  adjusted  to  them.  The  shape 
of  the  arch  prevents  one  placing  the  film  in  the  best  position  to  receive 
the  shadow,  viz. :  in  parallel  planes.  This  produces  a  distortion  which 
must  be  overcome  by  placing  the  source  of  the  light  in  just  the  position 
that  will  shorten  the  shadow  just  the  extent  that  will  correct  the  elonga- 
tion of  it  produced  by  the  film  not  being  in  a  parallel  plane  to  the  roots 
of  the  teeth.  We  do  not  have  this  trouble  with  the  lower  bicuspids 
and  molars,  but  we  do  with  the  lower  cuspids  and  incisors,  and  with 
all  the  upper  teeth. 

"The  correct  image  can  be  secured  in  two  ways,  by  holding  the 
film  away  from  the  crowns  of  the  teeth  the  same  distance  that  it  is 
away  from  the  roots,  or  by  raising  the  source  of  the  rays.  The  former 
is  more  difficult,  and  the  results  are  not  more  satisfactory.  The  three 
diagrams  shown  in  Fig.  391  will  illustrate  this  distortion,  and  how  to 
correct  it. 


568  APPLICATION    OF    THE   ROENTGEN   RAY   TO    DENTISTRY. 

"  Fig.  I  shows  diagramatically  the  relation  of  the  tooth  and  the  film 
to  each  other,  and  the  result  of  taking  a  skiagraph  with  the  tube  oppo- 


FlG.  391. 

site  and  at  right  angles  to  the  plane  of  the  teeth,  and  shows  the  distor- 
tion by  elongating  the  shadow  of  the  root.     The  skiagraph  A  opposite 


APPLICATION    OF    THE    ROENTGEN   RAY    TO    DENTISTRY.  569 

was  made  with  the  tube  in  this  position,  and  you  will  notice  the  very 
long  roots,  nearly  twice  the  correct  length.  Fig.  2  shows  the  distortion 
by  placing  the  tube  so  that  the  rays  fall  at  right  angles  to  the  plane  of 
the  film,  thus  greatly  shortening  the  shadow  of  the  roots.  The  skia- 
graph B  opposite  shows  the  same  teeth  as  A,  but  taken  with  this 
position  of  the  tube.  The  next  Fig.  3  shows  the  correct  position  for  the 
tube,  in  order  to  produce  a  shadow  of  the  teeth  that  will  have  the 
minimum  of  distortion,  and  the  skiagraph  C  opposite  shows  the  same 
teeth  as  A  and  B  taken  from  this  position,  and  you  will  note  easily 
the  difiference  in  the  results." 

Guided  by  the  above  clear-cut  instructions  of  Dr.  Price,  the  student 
must  study  carefully  the  angle  at  which  he  poses  his  patient,  and  if  the 
result  is  not  good,  he  must  reason  out  the  "why,"  and  endeavor  to 
correct  the  fault  next  time.  With  the  patient  in  the  dental  chair,  the 
writer  "gets  a  line"  on  the  path  which  he  thinks  the  rays  should  take, 
and  then  with  a  blue  pencil  makes  a  dot  on  the  exact  spot  upon  the 
face  upon  which  he  will  focus  the  rays,  and  this  simple  expedient 
assists  him  wonderfully. 

And  right  here  is  where  the  very  great  advantage  of  the  rubber 
covering  of  the  film  is  shown.  If  our  film,  of  standard  size  as  pre- 
pared, proves  too  large  or  not  the  best  shape,  it  is  taken  into  the  dark 
room  and  quickly  cut  to  the  desired  size  and  shape,  and  the  edges  of 
the  rubber  pinched  together.  It  is  obvious  that  for  skiagraphing  a 
lower  cuspid  situated  as  it  is  in  the  sharp  curve  of  the  arch,  that  a  film 
only  about  five-  or  six-eighths  of  an  inch  wide,  held  snugly  against  the 
arch  would  give  a  better  result  than  a  square  film  one  and  one-quarter 
inches  wide  in  a  stiff  paper  covering. 

Returning  to  our  proposed  experimental  picture,  the  resistance 
is  all  cut  out  at  the  rheostat,  the  full  twelve-inch  spark  gap  is  opened 
on  the  coil,  a  one-half  inch  series  spark  gap  is  left  at  the  tapes,  and  the 
third  terminal  is  adjusted  to  a  four-inch  gap. 

Focal  Distance. — ^A  word  about  the  focal  distance  for  taking  skia- 
graphs. The  effects  of  the  X-ray  upon  the  photographic  film  depends 
upon  the  distance  between  the  film  and  the  tube;  the  greater  the  dis- 
tance the  longer  must  the  exposure  be.  Believing  that  no  bad  results 
may  be  expected  from  very  close  exposures  of  from  one  to  three-  sec- 
onds when  all  precautions  are  taken,  the  writer  sees  every  advantage 
in  short  close  exposures,  and  such  is  his  practice. 

Our  patient  is  now  seated  in  the  chair  with  head  placed  in  the 
proper  position.  We  examine  the  roof  of  the  mouth,  and  remembering 
Dr.  Price's  instructions,  get  a  mental  line  as  to  what  angle  the  rays 


570  APPLICATIOM    OF    THE    ROENTGEN    RAY    TO    DENTISTRY. 

should  strike  the  lihn,  draw  the  tube  over,  and  adjust  it  in  position 
with  the  position  finder  in  range  with  the  apex  of  the  roots  of  the  cen- 
trals, as  nearly  as  we  can  judge.  The  position  finder  is  then  removed, 
the  film  placed  in  position,  and  the  patient  directed  to  hold  it  there, 
pressing  it  firmly  against  the  roof  of  the  mouth  with  the  thumb  of 
either  hand,  the  fingers  being  closed  in  on  the  palm  in  order  to  be  out 
of  range,  and  the  lower  teeth  closed  up  gently  against  the  thumb,  in 
order  to  steady  the  lower  jaw. 

Taking  the  Skiagraph. — A  glance  verifies  the  position  of  rheostat 
lever  terminals  and  connections— //ffs  final  glance  is  always  taken — and 
then  the  switch  is  closed  coincident  with  which  motion,  the  following 
sentence  is  begun.  "George  Washington  one,"  and  with  the  "one" 
completed,  the  switch  is  quickly  opened.     This  means  that  an  exposure 


Fig.  392. — From  left  to  right:  Lead  box  for  four  by  five  films.  Clips.  Develop- 
ing tubes  and  jars.  Pad,  pencil,  scissors  and  pliers.  Examination  box.  Box  of 
small  envelopes.  Two  small  lead  boxes  for  cut  films.  Red  and  black  rubber.  Devel- 
oping box  and  cover,  iron  box  for  stock  films,  black  paper  and  film  cutter. 

of  practically  one  second  has  been  made.  While  a  stop  watch  may  be 
used  for  accuracy  the  counting  oflf  of  seconds  in  this  manner,  George 
Washington  one,  George  Washington  two,  George  Washington  three 
and  so  on,  will  be  sufficiently  accurate  if  the  operator  will  practise  a 
little  with  a  watch  so  as  to  get  the  proper  speed.  The  exposure  having 
been  completed,  the  tube  is  swung  out  of  the  way,  the  film  packet 
removed  from  the  patient's  mouth,  and  the  next  step  is  its  development. 

The  Developing  System. — ^The  writer's  system  of  developing  his 
skiagraphs  was  devised  to  meet  his  immediate  requirements,  which  are 
that  such  work  is  usually  done  incidentally,  while  other  work  is  being 
carried  on,  and  no  one  person  exclusive  time  is  devoted  to  it,  and 
the  danger  of  accidentally  spoiling  a  skiagraph  must  be  reduced  to  the 
minimum,  if  not  altogether  eliminated. 

By  having  the  different  solutions  in  use,  each  always  in  some  dis- 


APPLICATION    OF    THE    ROENTGEN   RAY    TO   DENTISTRY.  57 1 

tinguishing  jar,  anyone  of  several  persons  can  go  into  the  dark  room, 
take  up  the  work  in  hand,  and  continue  it  without  any  instructions  from 
his  or  her  predecessor.  These  jars  occupy  less  space  than  dishes  or 
other  vessels,  and  require  the  minimum  quantity  of  solution. 

The  Developing  Box. — ^The  developing  of  films  in  these  jars  takes 
place  in  a  galvanized  iron  box  with  a  deep  cover.  In  this  manner  much 
of  the  developing  and  fixing  processes  proceed  in  the  dark.  The  cover 
rendering  the  box  light  proof,  the  work  can  be  left  in  safety  while  the 
operator  leaves  the  room,  or  is  otherwise  occupied  with  the  light  on 
(Fig.  392). 

However,  one  of  the  greatest  advantages  lies  in  the  fact  that  these 
various  httle  jars  filled  with  their  respective  solutions  may  be  left 
in  place,  protected  from  extraneous  influences  for  three  or  four  days, 
during  any  hour  of  which  they  are  ready  for  instant  use.  As  long  as 
the  developing  solutions  remain  clear  and  colorless,  they  are  fit  for  use, 
and  the  fixer,  of  course,  may  be  used  a  dozen  times  or  more. 

Paraphernalia. — Ks  for  the  paraphernalia  used  in  the  dark  room  its 
name  is  legion,  and  in  order  to  save  time  one  must  have  all  that  may  be 
necessary.     The  following  are  upon  the  writer's  shelves: 

Five  by  seven-inch  developing  trays  (for  plates  or  large  films  oc- 
casionally used.) 

Four-ounce,  twelve-ounce  and  sixteen-ounce  beakers. 

Glass  rods. 

The  necessary  bottles  for  the  developers,  fixing  bath,  formalin, 
alcohol  and  thyoxidant. 

Seven  sets  of  one  and  one-half-ounce  jars  about  two  and  one- 
quarter  inches  deep,  each  set  being  distinguished  from  the  other  by 
its  color  or  shape.  One  galvanized  iron  developing  box  about  twelve 
inches  by  nine  inches  by  four  and  one-half  inches  deep,  with  loose 
cover  one  and  one-half  inches  deep.  Three  lead  boxes  for  films. 
Black  rubber  for  enclosing  films.  Red  rubber  for  backing  stereo- 
scopic films.  Clips  for  drying  films.  Envelopes  for  temporarily 
holding  films.  Pad  and  pencil  for  necessary  notes  to  be  made  at  the 
moment.  Pliers  for  pinching  the  edges  of  rubber  together.  Scissors. 
Black  paper  for  patterns. 

Some  tap  water  is  unfit  for  photographic  work.  The  operator 
should  learn  from  some  local  photographer  whether  or  not  his  supply 
is  suitable,  and  if  not  distilled  water  should  be  used  for  the  solutions. 
Tap  water  can  be  usually  used  for  washing. 

The  writer  has  naturally  tried  very  many  developing  agents,  and 
has  finally  settled  down  to  the  exclusive  use  of  the  following  which 


572  APPLICATION   OF   THE   ROENTGEN   RAY   TO   DENTISTRY. 

in  his  hands  appear  to  yield  the  best  results  month  in  and  month 

out. 

Developer  A. 

Water 12  ounces 

Metol 22  grains 

Hydrochinon 22  grains 

Sodium  sulphite  (dried) 97  grains 

Developer  B. 

Water 12  ounces 

Potossium  bromide 12  grains 

Sodium  carb.  (dried) 97  grains 

Keep  in  well-stoppered  bottles;  if  after  long  standing  they  become 

discolored  they  should  be  discarded.     This  is  used  for  starting  the 

developing.     When  ready  to  develop  take  equal  parts  A,  B  and  water; 

mix  well. 

Developer  C. 

Water 10  ounces 

Sodium  sulphite  (dried) f  ounce 

Sodium  carbonate  (dried) \  ounce 

Hydrochinon i  dram 

Potassium  bromide 7^  grains 

Use  full  strength  for  completing  the  development 

Fixing  bath. 
No.  I. 

Water i  quart 

Hypo-sulphite  of  soda 8  ounces 

No,  2. 

Water 8  ounces 

Sulphate  of  soda f  ounce 

Powdered  chrome  alum \  ounce 

Sulphuric  acid -^^  ounce 

Immediately  add  No.  2  to  No.  i  while  stirring.  This  will  keep 
indefinitely  before  using.  This  fixing  bath  can  be  used  repeatedly, 
hardens  the  film  somewhat  and  gives  a  uniformly  better  result  than  a 
plain  solution  of  one  ounce  hypo  to  four  ounces  of  water,  though  the 
latter  can  always  be  fallen  back  upon  in  an  emergency.  Should  be 
filtered  when  necessary. 

For  hardening  the  film  (to  be  used  in  warm  weather)  immerse  the 

film  for  five  minutes  in 

Formalin 5  parts 

Water 95  parts 

For  quickly  eliminating  the  hypo,  the  film  should  be  first  rinsed 
under  the  tap  for  two  minutes  then  immersed  for  five  minutes,  no 
longer,  in: 

Lumierre's  thyoxidant i  part 

Water 100  parts 

and  then  washed  again  under  the  tap  for  three  minutes. 


APPLICATION   OF   THE   ROENTGEN   RAY   TO   DENTISTRY.  573 

Returning  to  the  work  of  developing  the  skiagraph  just  taken,  the 
developing  box  is  put  in  the  sink.  In  this  box  at  its  left  end  is  placed 
one  of  the  white  jars  into  which  is  put  one-half  ounce  each  developer, 
A,  B  and  water  Next  to  this  jar  is  placed  a  jar  of  water  for  rinsing, 
then  a  little  blue  jar  filled  with  the  C  developer  and  lastly  a  brown  jar 
full  of  fixer. 

It  is  possible  in  cool  weather  to  develop  a  film  in  a  single  develop- 
ing solution,  fix  it  in  plain  hypo,  wash  it  under  the  tap  and  hang  it 
up  to  dry.  The  results  obtained  in  this  simple  way  are  not  always 
the  best,  and  will  not  suffice  at  all  in  warm  weather. 

Moreover  this  is  somewhat  a  lengthy  process  and  ofttimes  a  picture 
must  be  finished  in  short  order.  So  then  while  additional  steps  must 
be  taken,  at  times  these  curtail  the  time  required  and  eliminate  all 
possibilities  of  "frilling"  the  films  in  warm  weather. 

Temperature  of  Developer. — The  best  results  are  obtained  when  the 
developing  solution  is  at  a  temperature  of  between  sixty  and  seventy 
degrees.  Should  the  temperature  be  above  seventy  degrees,  put  an 
inch  of  water  in  the  developing  box  and  a  few  pieces  of  ice. 

With  one  of  the  little  lead  boxes  at  hand,  we  darken  the  room  and 
turn  on  the  ruby  lamps.  The  films  are  removed  from  the  black  rubber 
by  tearing  off  one  end  of  the  rubber,  and  opening  it 
up.  One  film  is  placed  in  one  of  the  little  envelopes 
(previously  labeled  with  the  patient's  initials)  and  put 
in  the  lead  box  and  covered  and  the  other  is  placed  in 
the  end  of  a  developing  tube,  emulsion  surface  toward 
the  center,  and  immersed  in  the  white  jar  (left  end) 
given  several  vertical  shakes  to  remove  any  air  bubbles 
from  the  surface  of  the  film,  and  left  there  (Fig.  393). 

Both  films  are  never  developed  at  the  same  time, 
for  should  white  light  accidentally  be  let  in,  only  the         pj^  ^q, 
one  would  be  spoiled,  and  the  other  could  be  fallen 
back  upon.     As  a  matter  of  fact  the  duplicate  film  is  rarely  developed; 
usually  only  when  some  defect  or  accident  mars  the  first.     Sometimes 
it  is  developed,  and  given  to  the  patient  though  this  is  seldom. 

The  cover  of  the  developing  box  should  now  be  put  on,  in  order  to 
keep  the  ruby  light  from  the  film,  and  we  wait  for  about  a  minute. 
Upon  opening  the  box  we  now  see  the  advantage  of  having  the  film  in 
the  tube,  as  by  grasping  the  end  of  the  tube  which  stands  out  of  the 
solution,  we  remove  it  and  the  enclosed  film  for  examining  near  the 
ruby  light  without  getting  any  of  the  solution  on  our  fingers,  or  en- 
dangering the  film  by  handling.     If  the  dark  outlines  between  the  roots 


574  APPLICATION    OF   THE    ROENTGEN   RAY   TO   DENTISTRY. 

of  the  tooth  are  not  well  developed,  the  film  must  be  returned  to  the 
same  jar  for  another  short  period.  As  soon  as  this  stage  is  reached, 
that  is,  the  dark  streaks  are  well  visible,  the  film  is  immersed  in  the 
next  jar  (water)  for  rinsing,  and  then  put  in  the  adjacent  blue  jar  which 
contains  the  contrast  developer,  and  the  box  covered. 

We  examine  this  film  from  time  to  nme,  keeping  it  near  the  ruby 
light  as  little  as  necessary  until  the  white  spots  have  about  faded  out 
of  sight,  and  the  film  is  almost  black  all  over,  when  it  is  again  rinsed 
in  the  water  jar,  and  placed  in  the  fixing  bath  (brown  jar).  The  cover 
of  the  box  can  then  be  put  on,  and  we  can  go  off  for  ten  minutes,  at 
the  end  of  which  time  the  fixing  will  be  complete.  This  is  determined 
by  the  film  being  black  on  both  sides.  If  it  is  not  thoroughly  fixed,  it 
will  show  white  on  the  back  of  the  film.  When  the  whitish  aspect 
of  the  film  has  entirely  disappeared,  it  is  said  to  be  "cleared,"  and  a 
film  should  be  allowed  to  remain  in  the  fixing  bath  in  order  to  be 
thoroughly  "fixed  out,"  about  twice  as  long  as  it  takes  to  clear  it. 

Hardening  the  Film. — ^The  skiagraph  may  now  be  removed,  rinsed 
and  examined,  but  it  must  not  be  held  very  near  an  electric  lamp  or 
the  heat  will  spoil  it.  It  is  rinsed  again  in  the  cool  water  in  the  box 
(rinsing  it  under  the  tap  might  ruin  it)  and  then  placed  in  the  formalin 
for  five  minutes;  no  longer.  This  hardens  the  film  so  that  it  can  now 
be  rinsed  under  the  tap,  even  in  warm  water  for  thirty  minutes,  after 
which  it  can  be  hung  up  by  a  clip,  preferably  in  front  of  an  electric 
fan  to  dry. 

An  automatic  washing  and  drying  machine  was  devised,  in  which 
films  could  be  placed,  and  required  no  further  attention.  These  films 
were  washed  for  a  predetermined  length  of  time,  and  then  automat- 
ically dried,  but  the  scheme  was  not  found  very  satisfactory  in  actual 
use  and  was  therefore  abandoned. 

Right  here  must  be  emphasized  the  fact  that  unless  the  hypo  is 
thoroughly  eliminated,  the  film  will  be  found  to  have  become  spoiled 
in  the  course  of  a  few  months,  and  the  student  will  naturally  ask  what 
amount  of  washing  is  really  necessary  for  this  thorough  elimination  of 
the  hypo.  The  length  of  time  absolutely  necessary  for  this  washing 
should  be  determined  by  each  operator  for  himself,  after  which  he  may 
feel  safe  for  the  permanency  of  his  work,  and  this  is  ascertained  as 
follows : 

Test  for  Hypo. — ^Make  the  following  stock  solution: 

Permanganate  of  potash 8  grains 

Caustic  soda 7  grains 

Water  (distilled) 8  ounces 


APPLICATION    OF    THE    ROENTGEN   RAY    TO    DENTISTRY.  575 

Into  a  small  tumbler  of  pure  water  pour  four  drops  of  the  above 
solution  and  stir  well.  This  makes  a  solution  of  a  delicate  purple 
hue,  and  we  know  that  if  a  little  hypo  is  added  to  this,  it  will  turn  to  a 
greenish  hue  in  about  seven  minutes.  Taking  a  finished  film  out  of 
the  fixing  bath,  it  is  washed  for  twenty  minutes  under  the  tap,  and 
then  allowed  to  drain  into  the  above  solution,  and  after  a  few  minutes 
we  will  probably  find  that  the  stated  reaction  ensues,  and  therefore  we 
know  the  film  is  not  j^et  cleared  of  hypo.  After  washing  it  ten  minutes 
more  under  the  tap,  we  test  it  again  as  before,  when  we  find  no  reaction, 
consequently  we  may  feel  assured  that  thirty  minutes  of  washing  is 
necessary,  and  that  should  then  be  adopted  as  the  minimum  time  all 
films  will  be  washed.  Naturally  when  time  allows,  it  will  be  wise  to 
wash  them  a  little  longer,  but  never  less. 

Hastening  the  Work. — No  matter  how  pressed  for  time,  just  so 
many  minutes  will  be  necessary  for  properly  developing  and  fixing  the 


Fig.  394. 

film.  However,  by  rinsing  it  for  two  minutes,  then  immersing  it  for 
five  minutes  in  Lumierres'  Thyoxidant  (a  hypo  eliminator)  and  then 
washing  it  under  the  tap  for  three  more  minutes,  all  the  hypo  should 
be  eliminated — thus  twenty  minutes  have  been  saved  by  that  process. 
Again  if  it  is  immersed  in  grain  alcohol  for  three  minutes,  it  may  then 
be  dried  before  an  electric  fan  in  three  minutes  more,  thus  saving 
much  time  in  that  step.  To  prevent  curling  during  this  process,  the 
film  should  be  held  by  two  clips  as  shown  in  Fig.  394. 

Improving  Skiagraphs. — ^When  a  photographic  plate  is  overexposed 
or  underexposed  means  may  be  taken  for  reducing  the  one,  or  intensify- 
ing the  other,  but  the  writer  has  met  with  no  success  in  improving  un- 
satisfactory skiagraphs.     This,  however,  should  not  deter   the  student 


576  APPLICATION   OF   THE   ROENTGEN   RAY   TO   DENTISTRY. 

from  making  such  attempts,  and  determining  for  himself  what  is 
possible  in  this  line. 

Lead  Backing. — ^It  has  been  frequently  stated  that  better  results 
will  be  obtained  if  the  film  is  backed  by  a  piece  of  one-sixteenth-inch 
lead  when  being  exposed,  but  repeated  experiments  have  shown  that 
with  the  writer's  technique  at  least,  the  lead  makes  no  appreciable 
difference,  and  he  never  uses  it. 

Sizes  of  Films.— Films  up  to  two  by  two  and  one-half  inches  in  size 
may  be  developed  in  the  writer's  tubes  and  jars,  but  all  over  that  size 
must  be  developed  in  the  usual  photographer's  trays,  or  saucers  may  be 
used,  in  which  case  the  film  is  best  handled  by  a  clip  caught  on  to  one 
corner. 

Making  Photographic  Prints. — ^For  all  practical  purposes  the  films 
are  all  that  are  required,  more  especially  as  certain  essential  details 
may  not  appear  upon  the  prints.  However,  prints  are  necessary  at 
times,  therefore  the  operator  should  obtain  the  latest  paper  on  the 
market,  accompanying  which  will  come  full  directions  for  its  use,  and 
with  his  knowledge  of  developing,  he  should  have  no  trouble  in  making 
excellent  prints,  but  if  he  can  get  this  done  by  some  photographer 
who  makes  it  his  business  to  do  "amateur"  work  it  would  probably 
be  advisable. 

The  developing  of  his  films,  however,  should  be  done  in  his  office,  if 
not  by  himself,  by  one  of  his  assistants  under  his  directions,  who  should 
thus  be  able  to  obtain  more  satisfactory  results  than  anyone  else. 

Bromide  Paper. — In  the  earlier  days,  when  the  development  of  a 
skiagraph  required  a  very  long  time,  frequently  an  hour  or  more,  a 
piece  of  bromide  paper  would  sometimes  be  put  in  with  the  film  or 
plate,  which  after  exposure  could  be  quickly  developed  and  so  a 
finished  picture  produced  in  much  less  time  than  required  for  the  film 
or  plate.  But  these  bromide  pictures  were  always  lacking  in  detail, 
and  therefore  never  very  satisfactory,  and  in  view  of  the  rapid  work 
now  done,  this  paper  is  no  longer  used. 

Consulting  a  Photographer. — Any  beginner  in  X-ray  work  who  has 
had  no  experience  in  ordinary  photographic  work,  and  is  not  familiar 
with  its  details  had  better  call  to  his  aid  some  good  film  developer  who 
can  give  him  many  pointers,  and  by  an  actual  demonstration  of  the 
process,  save  him  much  time  which  would  be  otherwise  spent  in  lonely 
experimentation.  After  that  he  must  work  out  in  his  own  way  the 
troubles  he  meets. 

Deterioration  of  Films. — ^Unexposed  films  and  plates  deteriorate 
with  age,  and  just  how  long  they  may  be  kept  and  still  be  good  depends 


.\PPLICAT10N   OF   THE   ROENTGEN   RAY   TO   DENTISTRY.  577 

upon  the  season  of  the  year,  climatic  and  other  influences.  Usually 
they  keep  better  in  winter  than  in  summer,  but  the  best  plan  is  for  the 
operator  to  obtain  them  in  small  lots  and  frequently. 

Testing  Films.— To  test  a  film,  develop  it  without  having  exposed 
it.  If  it  comes  out  of  the  fixing  bath  clear,  it  is  good,  but  if  it  comes 
out  cloudy  and  dark,  it  shows  the  emulsion  has  deteriorated,  and  the 
balance  of  that  lot  must  be  discarded. 


DENTAL  SKIAGRAPH 

BY 

Dr.  C.  Edmund  Kells. 


No Date 

M 

Age 

Examined  for 


Make  of  Plate. 

Time 

Distance    

Developer 

Tube 

Remarks 


Fig.  395. 


Filing  Skiagraphs. — Some  operators  who  use  films  of  a  certain  size 
only  for  all  cases,  have  cardboard  or  celluloid  "mounts"  in  which  the 
films  are  placed  and  filed  away  (Dr.  Satterlee,  Jr.,  has  gotten  up  a  very 
attractive  celluloid  mount)  but  as  the  writer  does  not  limit  his  work  to 

37 


578  APPLICATION    OF    THE    ROENTGEN    RAY   TO    DENTISTRY. 

the  possibilities  of  any  one  size  and  shape  of  film,  but  cuts  them  to  best 
suit  the  case  in  hand,  he  cannot  use  such  a  method. 

Skiagraphs  are  taken  on  films  ranging  from  two  by  two  and  one- 
half  inches  (when  they  are  placed  horizontally  in  the  mouth  between 
the  teeth)  down  to  five-eighths  by  one  and  one-eighth  inches  for  lower 
cuspids,  and  cut  to  the  shape  most  suitable  to  the  case  in  hand.  They 
are  properly  "  tagged,"  as  will  be  described,  and  put  in  prepared  envel- 
opes (Fig.  395)  and  filed  away  alphabetically  in  suitable  boxes,  and  so 
any  skiagraph  may  be  quickly  found,  no  matter  how  long  since  it  has 
been  taken. 


Fig.  396. 

Marking  Skiagraphs. — ^In  taking  skiagraphs  upon  plates  of  any  size, 
there  is  always  plenty  of  room  thereon  for  any  required  marks  of  identi- 
fication, the  usual  one  being  to  place  small  lead  or  brass  numbers  or 
stencils  upon  the  outside  of  the  plate  holder,  which  being  opaque  to 
the  rays,  would  show  upon  the  plate.  However,  when  it  comes  to 
using  films  within  the  mouth,  this  method  though  early  used  by  most 
operators,  has  been  practically  abandoned  as  unsatisfactory,  and  no 


APPLICATION    OF    THE    ROENTGEN   RAY   TO    DENTISTRY.  579 

Other  system  being  used,  films  have  not  generally  been  marked,  and 
there  was  no  means  of  identifying  them.  This  has  been  a  constant 
source  of  worry  to  the  writer,  until  recently,  when  it  occurred  to  him 
to  tag  his  films,  and  since  this  system  has  been  put  into  practice,  it  has 
proven  to  be  all  that  can  be  desired. 

Small  merchandise  tags  are  used,  upon  which  can  be  written  all 
that  is  necessary,  and  as  they  need  never  be  removed,  a  film  can  ever 
after  be  identified  (Fig.  396). 

There  are  times,  however,  when  some  identification  mark  must  be 
recorded  upon  the  film.  Suppose,  for  instance,  a  patient  presents  for 
which  skiagraphs  of  both  lower  third  molars  are  desired.  Before  tak- 
ing the  right  one,  some  small  metalhc  object,  a  small  lead  R  for  in- 
stance is  placed  upon  the  outside  of  the  packet  upon  the  surface  pre- 
senting toward  the  tube,  care  being  taken  that  this  does  not  come 
right  behind  a  gold  crown  or  extensive  filling,  and  is  outside  of  the  area 
desired  in  the  field.  After  exposure,  if  this  precaution  has  been  taken, 
the  shadow  of  the  figure  will  be  found  upon  the  film,  and  it  is  only 
necessary  to  note  upon  its  tag,  that  this  marked  film  is  of  the 
right  side,  when  the  two  films  can  be  identified  with  their  respective 
sides. 

Recording  Skiagraphs. — When  a  patient  is  taken  into  the  dark  room 
for  the  purpose  of  having  a  skiagraph  taken,  a  lady  assistant  {absolutely 
necessary  when  the  patient  is  a  lady  or  young  girl)  follows  with  the  skia- 
graphic  record  book.  This  is  a  little  blank  book  in  which  she  always 
records  at  the  moment,  the  patient's  name,  and  the  length  of  the  ex- 
posure, and  also  makes  any  additional  notes  that  may  be  deemed 
necessary. 

Testing  Developing  Agents. — The  writer's  method  of  testing  the 
comparative  value  of  different  developers  is  as  follows:  to  compare 
Metol-Hydrochinon  with  Rodinol  for  example,  two  films  are  super- 
imposed and  enclosed  as  usual.  They  are  then  placed  in  the  mouth 
of  one  of  his  assistants  and  exposed. 

One  developing  jar  is  filled  with  the  Metol-Hydrochinon  developer, 
and  another  with  the  Rodinol,  and  placed  in  the  developing  box  along 
with  the  jars  of  water  for  rinsing  and  fixing  baths.  A  memorandum 
is  made  that  the  Rodinol  is  in  the  jar  nearest  the  operator.  The  room 
is  darkened,  red  lamps  turned  on,  the  packet  of  films  opened,  and  one 
placed  in  the  developing  tube,  and  then  immersed  in  the  Metol- 
Hydrochinon  developer.  The  second  film  has  one  corner  clipped  off 
and  placed  in  a  tube,  and  put  in  the  Rodinol,  and  a  note  made  that 
the  clipped  film  was  developed  in  the  Rodinol.     The  two  films  arj 


sSo 


APPLICATION    OF   THE   ROENTGEN   RAY   TO    DENTISTRY. 


then  carried  through  the  processes  of  developing,  fixing,  washing  and 
drying,  and  when  finished  they  can  be  readily  distinguished  from  each 
other  as  the  one  developed  in  Rodinol  is  indelibly  marked  by  the 
clipped  corner.  Upon  a  careful  examination,  it  can  be  seen  which 
developer  has  produced  the  better  results.  Naturally  the  student 
should  test  out  a  number  of  developers,  and  adopt  for  permanent  use 
the  one  which  suits  him  best. 

As  many  as  five  films  may  be  developed  at  once,  and  marked  for 
recognition  by  clipping  off  one,  two,  three  and  four  corners,  by  which 
they  may  be  distinguished  from  each  other,  and  from  the  fifth  which 
was  not  clipped  at  all.  This  method  of  marking  films  is  as  efficient  as 
simple,  but  care  must  be  taken  to  make  the  proper  notes  at  the  moment, 
and  not  rely  upon  one's  memory. 


Fig.  397. 


Skiagraphing  a  Lower  Molar. — ^To  skiagraph  a  lower  molar  or  bi- 
cuspid we  place  our  patient  in  the  dental  chair,  and'rapidly  make  a 
film  holder  as  shown  in  Fig.  387.  We  "get  a  line"  on  the  spot  on  the 
cheek  (with  the  mouth  nearly  closed)  opposite  the  apex  of  the  root 
of  the  tooth  to  be  skiagraphed,  and  mark  it  with  a  blue  pencil.  The 
film  is  then  attached  to  the  film  holder,  it  is  put  in  place,  the  teeth  closed 
upon  it,  and  the  patient  taken  into  the  dark  room. 

She  is  seated  at  right  angles  to  the  coil  as  shown  in  Fig.  397. 

The  tube  is  swung  into  position  and  adjusted  so  that  the  centering 
rod  points  to  the  mark  on  the  cheek,  while  the  tube  is  at  right  angles 
to  the  spot,  and  in  about  a  horizontal  plane.  The  localizer  is  removed, 
the  terminals  properly  connected,  a  final  glance  verifies  the  correct 


APPLICATION    OF   THE    ROENTGEN   RAY   TO    DENTISTRY.  581 

position  of  everything,  the  switch  is  closed  for  a  period  of  two  seconds 
(tissues  are  thick  here)  and  then  quickly  opened. 

With  the  film  thus  clamped  in  position,  and  the  jaw  closed  the 
patient  is  comfortable,  can  swallow  with  ease,  and  all  parts  can  be 
held  perfectly  still.  When  the  patient  is  holding  the  film  with  the 
finger,  swallowing  is  difiicult,  and  possibly  just  at  the  instant  of  ex- 
posure, an  attempt  to  do  so  is  made,  under  which  circumstances  the 
film  may  be  moved  and  the  picture  spoiled. 

Testing  the  Ruby  Lamp. — ^If  the  light  from  the  ruby  lamp  is  too 
strong,  it  will  "  fog"  the  films  exposed  to  it,  by  which  term  is  meant  that 
films  developed  under  it  or  exposed  to  it  will  be  affected,  and  therefore 
will  darken  all  over,  and  be  ruined  under  the  process  of  development. 
As  some  makes  of  films  are  more  susceptible  to  the  red  rays  than  others, 
it  becomes  necessary  for  each  operator  to  test  out  his  own  lamps,  which 
is  done  as  follows:  Take  a  piece  of  film,  say  of  the  usual  size,  one  and 
one-quarter  inches  by  one  and  one-half  inches,  and  cover  one-half  of 
it  with  a  sheet  of  black  paper,  and  lay  it  upon  the  top  of  the  develop- 
ing box  directly  under  the  ruby  lamp,  allowing  it  to  remain  there  for 
three  minutes.  At  the  end  of  this  time  develop  and  fix  it.  If  it  comes 
out  perfectly  clear  all  over,  it  shows  that  the  exposed  surface  was  not 
acted  upon  by  the  ruby  light,  and  that  the  lamp  is  therefore  safe.  If 
it  comes  out  with  one-half  clear  and  the  other  half  darkened,  it  shows 
that  the  half  not  protected  by  the  black  paper  was  acted  upon,  and 
therefore  that  the  lamp  is  not  safe.  This  may  be  remedied  by  placing 
a  piece  of  ruby  glass  under  the  lamp. 

The  operator's  own  ingenuity  should  be  exercised  in  fitting  up  his 
ruby  lamps,  placing  them  to  the  best  advantage,  and  possibly  arrang- 
ing them  with  extra  slides  of  ruby  glass,  by  which  more  or  less  light  can 
be  used,  always  remembering  that  the  less  light  on  the  films  the  better, 
and  that  their  rays  should  be  kept  from  the  films  as  much 
as  possible.  The  advantage  of  the  covered  developing 
box  is  here  made  manifest. 

Examining  Skiagraphs. — Skiagraphs  (films)  should  be 
examined  by  transmitted  light,  and  to  be  seen  to  the 
best  advantage,  all  light  rays  must  be  cut  off,  save  those 
that  pass  through  the  film.     The  writer's  scheme  for         ^^*  ^^ 
examining  films  of   various  sizes   and  five  by  seven-inch  plates  is  as 
follows: 

At  the  back  of  one  of  the  shelves  over  the  sink  in  the  dark  room, 
and  at  just  the  proper  height  three  Edison  plug  cutouts,  Fig.  398,  were 
screwed  to  the  shelf  and  frosted  8  C.  P.  electric  lamps  put  in  them  and 


582  APPLICATION    OF   THE    ROENTGEN   RAY   TO    DENTISTRY. 

SO  connected  to  two  switches  just  to  the  right,  and  under  the  shelf 
that  either  the  two  outside  lamps  could  be  lighted  at  once,  or  the 
center  one  only,  which  gives  a  satisfactory  range  of  illumination,  for 
with  these  connections  either  one,  two  or  three  lamps  can  be  lighted. 

Examining  Box. — Next  a  neat  wooden  box  ten  and  three-fourths  by 
seven  and  three-eighths  by  seven  and  one-half  inches  was  secured,  and 
from  it  two  adjacent  sides  were  removed.  In  the  third  side,  three 
holes  one-half  inch,  one  inch  and  one  and  five-eighths  inches  re- 
spectively were  bored,  and  over  these,  cardboard  shutters  were  pivoted 
by  means  of  glass-headed  pins.  In  the  fourth  side  an  opening  four 
and  one-half  by  six  and  one-half  inches  was  made  (Fig.  392). 

Now  with  one  open  side  down,  and  the  other  toward  the  back, 
this  box  is  placed  against  the  wall  and  over  the  lamps  with  the  three 
small  openings  in  front.  In  this  position  it  can  be  illuminated  by 
turning  on  the  switches,  and  the  shutter  is  swung  up  from  the  size 
opening  best  adapted  to  the  size  of  the  film  to  be  examined,  and  all 
undesirable  light  cut  off,  a  piece  of  sheet  metal  having  been  laid  over 
the  large  opening  on  the  top. 

The  film  to  be  examined  may  be  very  conveniently  held  by  placing 
it  in  a  holder  made  of  a  piece  of  ordinary  transparent  sheet  celluloid 
about  three  by  four  inches,  and  bent  upon  itself.  The  film  is  placed  in 
this  holder  at  one  end,  and  the  clip  holds  the  celluloid  together  (Fig.  396). 
If  one  always  cuts  his  films  of  a  standard  size,  the  celluloid  film  holder 
devised  by  Dr.  Satterlee  should  be  very  satisfactory,  but  as  the  writer 
cuts  his  film  to  suit  the  case  in  hand,  he  does  not  use  it. 

When  we  wish  to  examine  a  five  by  seven-inch  plate  this  box  is 
reversed,  bringing  the  large  opening  to  the  front.  Of  all  the  schemes 
for  examining  films  which  the  writer  has  ever  seen,  this  is  by  far  the 
most  satisfactory,  and  being  homemade  its  cost  consists  entirely  of  the 
little  time  spent  in  constructing  it. 

Interpretation  of  Skiagraphs. — Taking  a  skiagraph  is  usually  a  very 
simple  proposition,  but  properly  interpreting  it  is  ofttimes  a  much 
more  difficult  matter,  comes  only  with  practice,  and  cannot  be  taught 
by  the  "absent  method." 

Skiagraphs  are  purely  shadow  pictures,  and  consequently  their 
taking  must  be  governed  by  the  usual  laws  which  cover  the  casting  of 
ordinary  silhouettes.  The  lower  teeth  give  the  best  results,  as  here 
the  film  may  be  held  parallel  with  the  long  axes  of  the  teeth  and  the 
tube  so  placed  that  its  rays  will  strike  both  film  and  teeth  at  right  angles. 

In  skiagraphing  the  upper  teeth,  it  is  never  possible  to  place  the 
film  parallel  with  the  teeth  and  therefore  the  shadows  are  liable  to 


APPLICATION    OF    THE    ROENTGEN    RAY    TO    DENTISTRY.  583 

distortion,  which  however,  may  be  lessened  considerably  by  the  care- 
ful placing  of  the  tube  (see  page  570). 

The  relative  positions  of  the  various  details  shown  in  a  plain  skia- 
graph cannot  be  determined  therefrom,  therefore  it  is  usually  necessary 
for  the  operator  to  know  what  to  expect  in  order  to  correctly  interpret 
the  picture.  Thus  when  a  wire  is  placed  in  a  root  canal  one  cannot 
tell  from  the  resultant  skiagraph  (see  Fig.  414),  whether  the  wire 
was  anterior  or  posterior  to  the  root,  or  in  the  canal;  as  in  either 
position  the  shadows  cast  upon  the  film  would  be  about  the  same. 
However,  knowing  that  the  wire  was  placed  in  the  root  canal,  this 
skiagraph  can  be  read  intelHgently. 

The  enamel  is  least  penetrable  by  the  X-ray  and  therefore  appears 
white  on  the  filrn.  While  the  roots  of  the  teeth  are  more  penetrable 
than  the  enamel,  they  are  sufficiently  dense  to  cast  distinct  shadows 
upon  the  film  when  close  to  it.  It  is  often  impossible  to  show  the  buc- 
cal roots  of  upper  molars,  because  the  film  is  too  far  away,  and  cannot 
be  placed  upon  the  proper  plane,  but  the  lingual  root  may  be  clearly 
shown.  The  alveolar  process  between  the  teeth  and  above  (or  below) 
the  roots  is  quite  penetrable,  and  thus  these  parts  show  dark  upon  the 
film.  Metallic  fillings  and  metal  crowns  show  white,  while  porcelain 
being  very  penetrable  leaves  no  imprint  upon  the  film.  Fortunately, 
gutta-percha  and  cements  are  opaque  to  the  ray,  and  thus  root  fill- 
ings of  these  materials  may  be  readily  shown. 

Pus  sacs,  fistulous  tracts,  and  loss  of  tissues  generally  make  the 
region  involved  more  penetrable  than  the  surrounding  healthy  tissues, 
and  so  may  be  generally,  though  not  always,  recorded  upon  the  film. 
The  pulp  chambers  and  root  canals  are  well  shown  in  all  the  lower 
teeth  and  upper  single-rooted  teeth. 

If  something  appears  on  the  film  which  is  unrecognizable,  it  may 
be  due  to  an  artefact,  and  the  second  film  should  then  be  developed. 
If  it  should  be  duplicated  here,  and  still  not  be  understood,  a  second 
pair  of  films  should  be  exposed  when,  if  the  same  details  are  shown,  it 
will  be  recognized  that  whatever  it  is,  it  is  a  part  of  the  picture  and 
every  effort  should  be  made  to  interpret  it.  If  it  does  not  appear  on 
the  second  set  of  films,  it  proves  that  it  was  some  defect  in  the  first 
pair. 

Caution  must  be  used  and  no  hasty  conclusions  must  be  reached 
when  skiagraphs  are  not  perfectly  clear. 

Peridental  Membrane. — ^The  peridental  membrane  is  quite  trans- 
parent to  the  ray,  and  is  shown  in  nearly  all  pictures,  except  in  cases  of 
planted  teeth  where  it  usually  does  not  exist.     Usually  is  italicized  be- 


584  APPLICATION    OF   THE    ROENTGEN   RAY   TO   DENTISTRY. 

cause  in  Fig.  330  under  "Planting  of  Teeth"  is  shown  a  replanted  lower 
molar  in  which  the  membrane  is  shown,  the  only  case  of  its  kind  ever 
published,  the  writer  believes. 

The  Secondary  Ray. — ^The  secondary  ray  is  supposed  to  originate 
from  any  object  upon  which  the  direct  ray  from  the  tube  has  been 
thrown,  and  is  supposed  to  be  harmful.  The  writer  has  made  many 
varied  and  exhaustive  tests,  but  has  never  yet  been  able  to  have  the 
faintest  shadow  of  an  object  cast  upon  a  film  by  this  secondary  ray. 
While  it  is  impossible  to  discredit  what  others  claim  in  this  line,  he 
can  but  believe  that  for  some  unexplainable  reason,  this  ray  is  not 
created  in  his  own  laboratory,  and  every  operator  should  test  this  out 
for  his  own  satisfaction. 

Characteristics  of  the  X-ray. — ^The  value  of  the  X-ray  depends  upon 
its  remarkable  ability  of  penetrating  many  substances  that  are  imper- 
vious to  ordinary  light  rays,  but  there  is  no  relation  in  this  matter  be- 
tween the  two  classes  of  rays. 

Glass  free  from  lead  and  lead  glass  are  equally  transparent  to  the 
rays  of  light.  The  former  is  also  very  penetrable  to  the  X-ray,  while 
the  latter  in  any  thickness  is  quite  impervious  to  it. 

Aluminum  in  thin  sheets  is  quite  transparent,  while  lead  is  very 
opaque,  hence  the  use  of  the  former  for  filters,  and  the  latter  for 
protection  screens. 

The  bones  are  less  transparent  than  the  flesh,  and  hence  can  be 
seen  in  the  fluoroscope  or  shown  in  the  skiagraph.  The  roots  of 
teeth  are  also  fortunately  much  less  penetrable  than  the  alveolar  proc- 
ess in  which  they  are  imbedded,  and  therefore  can  be  shown  in  a 
skiagraph,  but  the  attenuated  end  of  a  root  may  sometimes  be  lost  to 
view  in  a  particularly  dense  jaw.  So  would  a  small  pulp  stone  be  in- 
visible if  situated  in  the  center  of  dense  enamel  or  even  dentin. 

The  uses  of  dental  skiagraphs  are  apparently  limited  in  a  great 
degree,  only  by  the  enthusiasm  and  imagination  of  the  operator. 
Some  can  distinguish  plainly  in  their  own  pictures  (where  others  fail 
to  see)  the  three  roots  of  an  upper  molar,  and  their  root  canal  fillings. 
Pulp  stones  stand  out  in  bold  relief  to  their  eyes.  They  can  tell 
whether  or  not  a  filling  is  dangerously  near  the  pulp  and  so  on.  To 
others  the  results  obtained  are  far  more  limited.  The  writer  belongs 
to  the  latter  class  and  while  he  has  not  been  able  to  accomplish  what 
some  others  claim,  the  results  obtained  are  invaluable,  and  if  the 
student  does  no  better  he  should  not  be  discouraged. 

Thus  far  skiagraphs  have  been  found  invaluable  to  the  ^ATite^  in  the 
following  cases. 


APPLICATION    OF    THE    ROENTGEN   RAY    TO    DENTISTRY. 


585 


To  Ascertain  to  which  Dentition  a  Tooth  belongs. — It  is  seldom  that 
the  character  of  a  tooth  cannot  be  safely  judged  from  its  appearance 
by  a  man  of  experience,  but  in  a  practice  of  thirty-five  years,  the  writer 
has  met  with  a  very  few  upon  which  there  could  be  a  doubt.     To 


Fig.  399.  Fig.  400. — The  dark  streak  diagonally 

across  the  root  is  an  artefact.  This  was 
one  of  our  earliest  skiagraphs  taken  on  a 
glass  plate. 

extract  a  permanent  tooth  under  the  impression  that  it  belonged  to  the 
first  dentition  would  be  a  fatal  mistake.  A  skiagraph  could  usually 
be  relied  upon  in  such  a  case  for  a  positive  diagnosis.  In  Fig.  399  is 
shown  a  permanent  second  bicuspid  in  the  mouth  of  a  Miss  which  was 
diagnosed  as  a  temporary  tooth  by  several  very  prominent  dentists. 
The  skiagraph  (Fig.  400)  proved  it  to  be  a  single-rooted  tooth,  there- 
fore a  permanent  bicuspid. 

Diagnosing  Unerupted  Teeth. — In  no  cases  are  skiagraphs  more 


Fig.  401. — Here  the  skiagraph  shows  Fig.  402. — While  here  it  is  seen  that  the 
that  the  temporary  molar  should  be-  ex-  second  bicuspid  is  missing  and  conse- 
tracted.  quently  the  temporary  molar  should    be 

preserved. 

satisfactory  than  in  diagnosing  the  presence  in  the  jaw,  or  the  absence 
therefrom  of  unerupted  teeth,  which  knowledge  is  usually  necessary 
for  the  successful  treatment  of  the  case. 

It  is  generally  considered  that  the  upper  cuspids  are  never  absent 


586 


APPLICATION    OF   THE    ROENTGEN    RAY    TO    DENTISTRY. 


from  but  always  somewhere  in  the  jaw.  Here,  however,  is  a  case 
which  appears  to  be  the  exception  to  the  rule,  the  only  authentic  one 
met  with  in  the  writer's  practice. 


Fig.    403. — Permanent    upper   second 
bicuspid   missing. 


Fig.  404. — Permanent  cuspid  erupted  in 
position  of  the  lateral.  Temporary  cuspid 
in  place.  Permanent  lateral  missing  (a  not 
uncommon  condition). 


Fig.  405. — Permanent  lateral  missing. 


Fig.  406. — No  lower  third  molar  present. 
Age  seventeen.     (Not  uncommon.) 


Fig.  407. 


APPLICATION    OF    THE    ROENTGEN    RAY    TO    DENTISTRY.  587 


Fig.  408. 

Root  Work  of  all  Kinds. — In  root  canal  work  of  all  kinds  the  uses 
of  skiagraphs  are  invaluable.  The  writer  early  in  his  X-ray  work 
devised  the  method  of  placing  fine  wires  in  the  roots  of  teeth  previous 
to  skiagraphing  them,  in  order  to  "get  a  line"  on  the  length  of  the 
roots,  size  of  apical  foramina,  etc.     He  frequently  skiagraphs  a  root 


Fig.  409. — Obtaining  the  length  of  lower         FiG.  410. — Note  the  absorption  of  pos- 
molar   roots.     (Note    the  loop  formed   on  terior  root, 

the  fine  platinum  point  upon  pressing  it 
down.) 


Fig.  4n. — "Getting  a  fine"  on  a  second  Fig.  412. — Diagnosing  a  perforated  root, 

bicuspid  root  canal.  Example  of  a  frilled  film. 


588  APPLICATION    OF    THE   ROENTGEN   RAY   TO    DENTISTRY. 

after  filling,  and  if  found  not  well  filled  it  is  changed  accordingly.  ,An 
entire  chapter  should  be  wTitten  on  this  one  subject  and  it  is  withue- 
gret  that  space  limits  the  work  to  a  few  illustrations  only; 


Fig.  413. — Size   of   apical    foramen    of        Fig.  414.— Obtaining  the  size  of  fora- 
upper  central.     Pulp  killed  at  age  of  seven  men  in  lateral  of  adult, 

by  faU. 


Fig.  415. — Same  in  child  of  about  eight.  Fig.  416. — .\bscess    on    lower    central, 

child    of    twelve.     No    cavity    in    tooth. 
Cause   unknown. 


Fig.  417. — Abscess   caused   by   imperfect         Fig.  418. — Abscess    on    upper    lateral, 
root  filling.  Wire  in  canal. 

To  Study  the  cmidilions  about  the  roots  of  planted  teeth  and  possibly 
to  skiagraph  the  alveolus  before  the  operation. 

A  condition  of  affairs  may  present  which  appears  unrecognizable. 


APPLICATION    OF    THE   ROENTGEN    RAY    TO    DENTISTRY.  589 

At  the  point  marked  upon  the  model  there  was  an  unrecognizable 
condition;  a  firm  particle  of  exposed  bone  could  be  felt  with  an  in- 


FiG.  419. — Posterior  canal  of  molar  ap- 
parently well  filled.  Anterior  canal  im- 
perfectly filled  and  large  pus  sac  at  its  apex. 


Fig.  420. — Same  case  few   days   later. 
Anterior  root  refilled. 


Fig.  421. — Skiagraphing  an  implanted 
lateral  brought  to  light  an  unknown  im- 
pacted cuspid.  "  The  point  only  of  the 
cuspid  is  shown  in  this  illustration,  but 
upon  the  original  film  much  of  the  crown 
was  visible." 


Fig.  422. — Central  incisor  knocked  out 
by  fall  (uninjured).     Replanted. 


Fig.  423. — Incurable    abscess    on    lower 
cuspid.     Tooth  replanted. 


Fig.  424. — Same  case  several  years  later. 
Pus  sac  obliterated. 


strument.  It  evidently  was  not  a  root  nor  was  it  the  alveolar  process. 
A  skiagraph  showed  it  to  be  a  bone  "whorl."  Skiagraph  was  kindly 
interpreted  by  Dr.  Raper. 


590 


APPLICATION    OF    THE    ROENTGEN    RAY   TO    DENTISTRY. 


To  A'scertain  if  a  Root  is  Fractured. — ^I'his,  however,  is  only  to  be 
discovered  by  the  merest  chance,  for  unless  the  line  of  fracture  happens 


Fig.  425. — A  hopelessly  broken-down  lower  molar  with  abscess  on  one  root  was 
extracted  and  unintentionally  put  in  a  porcelain  tray  and  placed  in  cabinet.  Few  days 
later  an  old  patient  called  with  the  left  upper  first  bicuspid  split  in  two.  It  was  ex- 
tracted. The  lower  molar  just  referred  to  was  carefully  split  and  the  good  root  put  in  con- 
dition, and  crowned  and  implanted  -n  place  of  split  bicuspid.  Skiagraph  was  taken 
several  years  after  the  operation. 


Fig.  426. 


Fig.  427. 


Fig.  428. — Upper  lateral  fractured  by  fall.     Fig.  429. — Lower  centfal  fractured  with- 
in the  alveolus  without  known  cause. 


to  lie  in  the  direct  path  of  the  rays,  it  will  not  be  shown,  therefore 
when  such  fracture  is  suspected,  if  the  first  skiagraph  does  not  show  it, 
others  at  different  angles  must  be  taken. 


APPLICATION    OF    THE    ROENTGEN    RAY    TO    DENTISTRY. 


591 


The  shape  and  position  of  impacted  teeth. 
Impacted  third  molar  shown  in  Fig.  315. 


Fig.  430. — An  impacted  cuspid  vvitfi  an  FiG.  431. — Impacted  cuspid  having 
odontome  between  the  roots  of  the  lateral  caused  the  absorption  of  the  root  of  the 
and  bicuspid.  permanent  lateral.     (Regulating  arch  bar 

shown.) 


Fig.  432. — An  unerupted  cuspid  in  the  FiG.  433. — The  root  of  a  temporary 
roof  of  the  mouth  of  an  edentulous  jaw.  cuspid  of  an  adult  was  crowned.  Later 
Patient  over  sixty  years  of  age.  on   trouble   ensued   and   a   skiagraph    re- 

vealed the  permanent  cuspid  as  .-^hown. 


Fig.  434. — Supernumerary     literal. 
Model  of  this  case  shown  in  Fi^'.  448. 


Fig    435       lourth  inohir. 


To  learn  whether  or  not  there  is  a  fragment  of  a  root  in  the  alveolus 
the  rays  are  invaluable,  but  as  a  rule  such  skiagrajjhs  are  loo  faint 
for  satisfactory  illustrations. 


592 


APPLICATION    OF   THE   ROENTGEN   RAY   TO    DENTISTRY. 


In  all  cases  of  facial  neuralgia  where  the  causes  are  not  discernible, 
skiagraphs  should  be  taken  in  the  hopes  of  some  hidden  cause  being 
revealed. 

To  diagnose  supernumerary  teeth. 


Fig.  436,  Fig.  437. 

Permanent  central  and  lateral  with  one  root. 


To  ascertain  whether  impacted  third  molars  have  injured  the  second 
molars.     (See  Figs.  323  and  324.) 

Fused  Teeth. — Sometimes  two  crowns,  usually  of  the  incisors,  are 
fused  and  it  might  be  well  to  learn  whether  or  not  they  have  single  or 
double  roots.     Again,  sometimes  the  roots  are  fused,  and  the  crowns 

appear  detached  when  again  a  skiagraph 
may  possibly  lead  to  some  definite  knowl- 
edge. 

Diseased  Antrum. — ^The  writer  believes 
that  any  antrum  that  can  be  shown  to  be 
.in  abnormal  condition  by  a  skiagraph,  can 
be  as  well  diagnosed  by  transillumination. 
That  being  the  case,  why  go  through  all 
the  various  time  consuming  steps  for  pro- 
ducing a  skiagraph,  when  the  same  result 
can  be  instantly  obtained  by  means  of  a 
suitable  electric  lamp. 
Any  foreign  object  within  the  antrum  can  probably  be  better  shown 
on  a  film  placed  within  the  mouth,  than  on  a  plate  held  externally. 

"  To  Diagnose  for  Extraction. — The  skiagraph,  Fig.  439,  assuring 
the  correct  position  of  the  unerupted  second  molar,  the  hopelessly 
broken  down  and  abscessed  first  molar  was  extracted. 


Fig.  438. — Temporary  lateral 
and  cuspid  fused.  Permanent 
lateral  missing. 


APPLICATION    OF    THE    ROENTGEN   RAY    TO    DENTISTRY. 


593 


In  Fig.  440  is  shown  the  case  six  years  later,  when  we  find  the 
second  molar  has  erupted  in  a  perfectly  vertical  position  in  contact 
with  the  second  bicuspid. 

Diagnosing  Caries. — While  some  operators  claim  that  cavities  that 
cannot  be  discovered  by  an  explorer  will  be  revealed  in  the  skiagraph, 
such  is  not  believed  to  be  the  case.  Any  cavity  too  small  (naturally 
upon  a  proximal  surface)  to  be  disclosed  by  an  explorer  will  not  show 
upon  the  film. 


Fig.  439.  Fig.  440. 

Fig.  439. — At  the  age  of  ten  a  badly  broken-down    first  molar  was  extracted,  a 
skiagraph  having  shown  the  second  molar  to  be  in  the  jaw. 
Fig.  440. — Model  shows  case  at  the  age  of  sixteen. 

Undoubtedly  many  other  uses  than  those  described  may  be  met  with 
in  which  skiagraphs  would  be  useful,  such  for  instance  as  fracture  of 
the  jaw,  the  thoroughness  with  which  bismuth  paste  has  been  injected, 
etc.  The  writer  could  only  well  describe  practical  cases  of  his  own,  and 
therefore  has  limited  himself  accordingly. 

The  proper  interpretation  of  a  skiagraph  may  be  at  times  a  very 
difficult  matter,  and  one  must  remember  that  being  merely  a  shadow 
picture  too  much  must  not  be  expected  of  it. 

Therapeutical  Value  of  X-ray. — ^At  this  date,  it  is  the  writer's  opinion 
that  there  is  no  place  in  dentistry  for  the  application  of  the  X-ray 
for  its  therapeutical  value. 


STEREOGRAPHS. 


Thus  far  we  have  treated  only  of  plain  skiagraphs,  simple  shadow 
pictures,  and  we  have  seen  that  the  proper  interpretation  of  such 
depends  entirely  upon  the  clinical  knowledge  of  the  case  as  when 
writing  of  Fig.  414,  it  was  noted  that  it  was  impossible  to  state  pos- 
tively  the  relative  positions  of  the  wire  and  root. 


594  APPLICATION    OF   THE   ROENTGEN   RAY   TO    DENTISTRY. 

If,  however,  the  same  laws  which  apply  to  the  ordinary  well-known 
form  of  stereoscopic  photographs  are  applied  to  X-ray  work,  and 
skiagraphs  are  taken  accordingly,  only  varying  the  technique  to  con- 
form to  the  requirements  of  this  work,  the  results  are  what  we  usually 
call  stereoscopic  skiagraphs,  but  what  the  writer  has  termed  "stereo- 
graphs" of  most  marvelous  beauty  and  great  accuracy. 

Most  of  the  doubtful  features  of  the  shadow  picture  are  elimi- 
nated in  the  stereograph.  In  the  place  of  a  flat  picture  without  per- 
spective, the  stereoscope  brings  into  view  a  translucent  model  as 
though  made  of  glass  with  the  various  tooth  roots  apparently  floating 
in  it,  while  they  themselves  are  also  transparent,  though  naturally 
less  so  than  the  alveolar  process.  The  root  canals  may  be  clearly  fol- 
lowed and  when  filled,  any  imperfections  in  the  filling  are  readily 
perceived.  Whether  or  not  a  crown  post  or  root  filling  perforates  the 
side  of  the  root  may  usually  be  told.  The  relative  positions  of  im- 
pacted or  unerupted  teeth  are  also  clearly  brought  into  view. 

Unfortunately  the  technique  for  making  stereographs  is  rather 
difl5cult,  or  possibly  it  might  be  better  stated  that  while  the  technique 
is  not  so  very  difficult  in  itself,  there  are  other  difficulties  in  the  way, 
and  as  a  result  this  work  has  not  yet  become  general. 

Assuming  that  the  reader  is  familiar  with  the  principle  of  stereo- 
scopic photography,  it  is  only  necessary  to  say  that  in  making  stereo- 
graphs we  proceed  in  the  same  manner,  that  is  by  taking  two  skia- 
graphs from  positions  two  and  one-half  inches  or  the  average  pupillary 
distance  apart,  care  being  taken  that  the  focus  in  both  pictures  is 
upon  the  same  point.  The  resultant  skiagraphs  are  then  properly 
mounted,  and  viewed  in  a  stereoscope  whereupon  the  stereograph  is 
the  result. 

The  requisites  for  making  stereographs  are: 

1.  A  tube  carrier  which  will  allow  of  the  quick  shifting  of  the 
tube,  preferably  along  the  arc  of  a  circle  the  necessary  distance  of 
two  and  one-half  inches  and 

2.  A  means  of  readily  replacing  the  first  film  by  a  second,  and  hav- 
ing them  both  in  practically  the  same  plane. 

For  doing  this  class  of  work  upon  the  body  generally,  there  are 
most  beautiful  and  accurate  appliances,  but  none  at  this  date  appear 
to  the  writer  sufficiently  flexible  for  using  films  within  the  mouth,  and 
so  appliances  were  originated  to  meet  his  own  requirements. 

By  replacing  upon  his  tube  carrier  clamp  E  (Fig.  385)  by  the  one 
shown  in  Fig.  441  the  tube  is  pivoted  at  F  and  swung  in  a  circle,  and 


APPLICATION   OF    THE    ROENTGEN    RAY   TO    DENTISTRY. 


595 


thus  this  tube  carrier  becomes  adapted  to  stereoscopic  work.     The 
focal  distance  of  the  tube  is  not  a  fixed  one  for  stereoscopic  work. 

The  stereograph  shown  in  Fig.  442  was  taken  as 
follows : 

Upon  the  black  portion  of  the  preparation  board 
two  pieces  of  ordinary  red  dental  rubber  each  two  and 
one-half  by  two  inches  were  placed,  and  alongside  of 
them  upon  the  white  portion  of  the  board  two  pieces 
of  black  rubber  of  the  same  size  and  also  a  black 
paper  pattern  two  and  one-fourth  by  one  and  three- 
fourths  inches. 

The  white  light  being  extinguished,  the  red  rubber 
is  readily  seen  against  the  black  background,  and  the 
black  rubber  and  black  paper  pattern  against  the 
white.  Now  follow  this  carefully.  Two  of  the  four 
by  five-inch  films  placed  together  with  emulsion  sur- 
faces in  contact  as  usual,  the  black  paper  pattern  laid 
on  them,  and  one  pair  cut  to  its  size,  the  corner  of  one 
only  cHpped  ofi',  and  then  they  were  laid  upon  the 
black  rubber  with  the  clipped  film  against  the  rubber, 
then  covered  with  one  of  the  prepared  pieces  of  red  rubber,  and  the 
edges  carefully  pinched  together. 


Fig.  441. 
They  were 


Fig.  442. 


Two  other  films  were  similarly  cut  and  arranged,  and  again  the 
clipped  film  was  placed  against  the  other  piece  of  black  rubber,  then 
covered  with  the  red,  and  edges  secured  together.     The  unused  por- 


596 


APPLICATION    OF   THE   ROENTGEN    RAY   TO   DENTISTRY. 


tions  of  the  films  were  replaced  in  the  lead  box,  and  box  immediately 
covered  and  put  in  its  place  upon  the  shelf. 

A  ligature  wire  was  twisted  around  one  of  the  cuspids  of  the  patient, 
another  piece  placed  between  the  opposite  cuspid  and  lateral.  She 
was  then  posed  and  her  head  steadied  to  the  rest  by  means  of  a  bandage 
around  the  forehead.  Next  the  tube  was  placed  in  position  and 
focused  approximately  upon  the  apices  of  the  centrals.  It  was  then 
shifted  one  and  one-fourth  inches  to  the  left,  and  the  patient  earnestly 
cautioned  not  to  move  until  permission  was  given.  One  of  the  pre- 
pared films  was  taken  out  of  the  room,  while  upon  the  other  a  small 
metal  L  was  placed  on  a  corner  of  the  black  rubber,  when  it  was 
placed  horizontally  in  the  mouth,  black  rubber  uppermost  with  the 
corner  upon  which  was  the  L  protruding  from  the  mouth.  The  teeth 
were  closed  gently  upon  it,  the  switch  closed,  and  thus  the  exposure 
made.  This  was  the  left  eye  picture  marked  L.  The  tube  was 
then  shifted  back  two  and  one-half  inches  to  the  right,  the  exposed  film 
removed  and  taken  out  of  the  room,  tht-  second  one  put  in  place,  black 
rubber  uppermost  and  exposed,  care  being  taken  to  give  both  films 
the  same  length  of  exposure.  It  will  be  noted  that  both  sets  of  films 
were  placed  in  practically  about  the  same  plane, 
provided  the  patient  did  not  move  during  the 
interval  that  the  films  were  exchanged. 

Upon  opening  these  in  the  dark  room,  the 
advantage  of  the  red  rubber  base  and  the  clipped 
films  becomes  apparent,  for  the  two  clipped  films 
form  one  pair,  they  having  been  exposed  with  the 
film  surface  away  from  the  tube,  while  the  un- 
dipped ones  form  another  pair,  and  pairs  register 
best  in  the  stereoscope.  When  mounting  them  in 
the  stereoscope,  the  advantage  of  having  the  left 
eye  skiagraph  identified  becomes  apparent.  Of 
course  other  means  may  be  taken  for  marking  the 
top  and  bottom  (clipped  and  undipped)  films, 
but  the  method  just  described  suits  the  writer  best. 

The  development  of  the  films  proceeds  exactly  as  with  the  plain 
skiagraphs,  care  being  taken  that  both  films  are  developed  to  the  same 
density.  With  the  finished  stereographs  in  hand,  the  next  problem 
becomes  their  examination,  and  here  again  the  writer  was  compelled 
to  resort  to  originality,  for  there  are  no  practical  small  stereoscopes 
made  for  this  purpose.  It  is  possible  of  course  to  make  prints,  and 
mounting  them  on  card  board  examine  them  in  the  ordinary  parlor 


Fig.  443. 


APPLICATION    OF    THE    ROENTGEN   RAY   TO    DENTISTRY. 


597 


stereoscope,  but  the  best  prints  are  vastly  inferior  to  the  original  films. 
The  apparatus  shown  in  Fig.  443  was  therefore  devised 

It  consists  of  an  ordinary  parlor  stereoscope  to  the  rod  of  which  is 
secured  a  rack  engaging  with  a  pinion  operated  by  the  little  wheel 


Fig.  444 

plainly  shown.  This  makes  it  adjustable  to  anyone's  eyes  as  by  turn- 
ing the  wheel  the  lenses  are  moved  up  or  down.  The  top  of  the  box  is 
of  ground  glass,  grooves  being  provided  by  which  two  or  three  other 
sheets  of  ground  glass  may  be  added  at  will,  that  the  light  from  the 
frosted  electric  lamp  within  the  box  may  be  toned  to  suit  stereographs 
of  various  densities.  Holes 
should  be  cut  in  a  piece  of  card- 
board so  that  when  laid  on  the 
glass,  all  extraneous  light  may 
be  cut  off  from  the  eyes  and 
thus  the  films  show  to  better 
advantage. 

For  examination  the  films  are 
placed  between  strips  of  clear 
glass  for  the  better  handling 
(Fig.  444)  and  placed  upon  the 
box  (the  left  eye  skiagraph  being 
recognized  by  the  L)  and  care-  ^^'  ^'^^' 

fully  moved  about  until  they  register,  while  at  the  same  time  the 
lenses  are  adjusted  to  the  proper  focus  by  the  little  hand  wheel.  Now 
the  advantage  of  having  placed  ligatures  about  the  cuspids  is  seen, 
for  by  their  aid  the  films  may  be  readily  registered,  while  without 
them  this  is  not  always  so  easily  accomplished. 


598  APPLICATION    OF   THE   ROENTGEN   RAY   TO   DENTISTRY. 

If  these  films  are  transferred  to  a  single  plate  three  by  seven  inches 
a  "transparency"  results,  and  when  this  is  placed  in  another  of  the 
writer's  stereoscopes,  Fig.  445,  the  stereoscopic  effect  is  most  beautiful. 

For  practical  every-day  office  work,  the  first  described  stereoscope 
is  the  quicker  and  more  satisfactory.  For  exhibition  purposes,  the 
latter  with  the  transparency  is  better,  as  there  is  only  one  plate  to  handle, 
and  it  may  be  very  quickly  focused  by  a  novice.  The  bellows  allow  of 
the  focusing  of  the  lenses  while  none  but  transmitted  light  strikes  the 
eyes. 

Stereographs  cannot  be  read  at  a  glance.  Some  little  time  is  required 
to  properly  focus  a  picture,  and  then  considerable  study  is  necessary  to 
bring  out  all  the  beautiful  details  that  lie  within  its  mysterious  depths. 


Fig.  446. 

Upon  placing  the  left  eye  picture  upon  the  left  end  of  the  examining  box, 
and  the  right  eye  picture  on  the  right,  the  object  stereographed  is  viewed 
from  the  point  from  which  the  pictures  were  taken.  But  if  the  stereo- 
graphs are  interchanged,  then  strange  to  say,  it  is  seen  as  from  the  inside 
of  the  mouth.  The  writer  much  prefers  to  study  these  cases  from  the 
latter  point  of  view. 

The  value  of  stereoscopic  work  is  beautifully  exhibited  in  the  fol- 
lowing case.  Fig.  446  represents  the  condition  found  in  the  mouth  of  a 
girl  of  ten.  Below  it  Fig.  447  are  two  plain  skiagraphs  of  the  unerupted 
central  taken  from  two  different  angles,  and  so  very  different  are  the 
shadows  cast,  that  it  is  hard  to  believe  that  they  are  of  one  and  the  same 
tooth;  and  furthermore,  save  that  the  tooth  was  in  the  jaw,  no  idea  as  to 
its  position  could  be  gained.  Upon  taking  a  stereograph,  however,  the 
true  position  of  the  tooth  could  be  seen. 

A  most  interesting  case,  and  one  in  which  the  stereograph  was 
invaluable,  is  shown  in  Fig.  448.  The  case  is  of  a  lovely  little  girl  of 
eight.     Apparently  three  teeth  are  erupting  in  the  space  usually  occu- 


APPLICATION    OF   THE    ROENTGEN    RAY   TO    DENTISTRY. 


599 


pied  by  the  one  lateral.  They  could  be  the  normal  lateral  and  two 
supernumerary  teeth,  or  one  of  these  might  be  the  permanent  cuspid. 
No  one  could  tell,  and  something  must  be  done.  To  extract  a  wrong 
tooth  or  teeth  for  such  a  patient  would  be  little  less  than  a  calamity.  In 
Fig.  434  is  shown  a  plain  skiagraph  of  the  case.     From  it  absolutely 


Fig.  447. 

nothing  can  be  learned,  but  from  stereographs  (two  sets  from  different 
angles)  is  learned  positively  that  the  two  bicuspids  and  cuspid  are  form- 
ing within  the  jaw,  and  that  there  are  only  two  teeth  erupting  and  not 
three  as  the  Httle  point  just  protruding  through  the  gum  is  an  excres- 
cence upon  the  lingual  surface  of  the  labial  tooth.     This,  one  observes, 


Fig.  448. 


is  most  valuable  information,  as  from  it  a  satisfactory  solution  of  the 
problem  is  possible,  that  is  the  removal  of  the  supernumerary  (labial) 
tooth. 

These  stereographs  are  not  shown,  because  while  perfectly  satis- 
factory in  themselves,  such  pictures  lose  so  much  in  being  reproduced 


6oO  APPLICATION    OF   THE   ROENTGEN   RAY   TO   DENTISTRY. 

by  the  halftone  process,  that  they  are  practically  of  little  value  as 
illustrations. 

These  two  cases  out  of  many  the  writer  has  had  are  sufficient  to 
demonstrate,  that  though  stereoscopic  work  may  be  somewhat  difficult 
and  tedious,  the  truly  wonderful  results  that  may  be  accomplished 
through  it,  render  it  worth  while  to  master  its  technique. 

Dental  X-ray  Operators. — ^The  writer  has  always  contended  that 
the  dentist  himself  should  do  skiagraphic  work  and  not  refer  his  cases 
to  a  general  X-ray  operator  and  for  the  following  reasons: 

1.  They  very  frequently  must  be  taken  at  the  instant  needed,  for 
example,  with  the  dam  on. 

2.  The  dentist  who  knows  exactly  what  he  wants  brought  out 
in  the  skiagraph,  is  much  more  apt  to  succeed  in  getting  it  in  the 
picture,  than  the  general  operator  who  knows  practically  nothing  of 
the  case. 

3.  With  the  skiagraph  developed  immediately,  if  it  does  not  prove 
satisfactory,  a  second  one  can  be  taken  with  the  loss  of  but  little  time. 

To  become  a  good  X-ray  operator  only  requires  practice,  attention 
to  details,  and  perseverance.  Just  as  a  good  light,  a  modern  chair^ 
an  electric  engine,  or  compressed  air  will  each  and  every  one  improve 
the  quality  of  the  "output"  of  a  dentist,  so  right  to-day,  no  matter 
how  high  his  qualifications  and  great  his  ability,  the  class  of  work  of 
any  one  will  be  improved  by  the  installation  and  successful  use  of  a 
first-class  Roentgen  Ray  apparatus  in  his  office. 

Owing  to  the  limited  space  available  many  topics  and  illustrations 
have  been  greatly  curtailed,  but  the  writer  trusts  that  sufl&cient  has 
been  given  to  start  the  student  upon  a  work  of  wonderful  interest  and 
satisfaction,  the  results  to  be  obtained  by  him  being  only  limited  by 
his  unceasing  devotion  to  its  study. 

Thanks  are  due  the  Scheidel- Western  X-ray  Coil  Co.,  Macalaster 
Wiggin  Co.,  Consolidated  Dental  Mfg.  Co.,  S.  S.  White  Dental  Mfg.  Co. 
and  Dr.  Price  for  some  of  the  cuts  used. 

GLOSSARY. 

A.  C.     Alternating  Current. 

Alopoecia.     Loss  of  hair. 

Am- Meter.     Device  for  registering  the  Amperes  flowing  through  the. 

line. 
Anode.     The  positive  terminal  within  the  tube. 
Artefacts.     Products  of  errors  or  reagents. 


APPLICATION   OF    THE    ROENTGEN   RAY    TO    DENTISTRY.  6oi 

Cathode.     The  negative  terminal  within  the  tube. 

Cathode  Stream.     Rays  being  emitted  from  the  cathode. 

Cleared.  (Photographic  term.)  Condition  of  film  when  hypo  has 
blackened  it  thoroughly. 

Cycles.  Frequency  of  alternations  per  second  in  an  alternating  cur- 
rent. 

Crooke's  Tube.  The  original  tube  used  in  X-ray  work  in  which  the 
vacuum  is  one  millionth  of  an  atmosphere. 

D.  C.     Direct  Current. 

Electron.     The  smallest  known  component  of  matter. 

Electrolyte.  (In  solution.)  A  substance  capable  of  being  decom- 
posed by  an  electric  current. 

Electromotive  Force.  (E.M.F.)  The  force  that  causes  electricity 
to  move  along  a  conductor. 

Erythema.     Redness  of  the  skin. 

Fluoroscope.     a  device  for  observing  shadows  cast  by  Roentgen  Rays. 

Frilling.  (Photographic  term.)  Emulsion  surface  becoming  wrinkled 
and  indecipherable. 

Fogged.  (Photographic  term.)  Denoting  that  the  film  has  been 
unduly  affected  either  by  Hght,  X-rays  or  chemicals. 

Hypo.     Hyposulphite  of  Soda. 

Light  Struck.  (As  applied  in  photography.)  When  white  light  has 
accidentally  spoiled  a  plate  or  film. 

Mil-Ameter.  Device  for  registering  the  milliamperes  flowing  through 
the  line. 

Ohm's  Law.  The  strength  of  an  electric  current  varies  directly  as  the 
E.M.F.  and  inversely  as  the  resistance. 

Penetrameter.  Gage  for  determining  the  degree  of  penetration  of 
X-rays. 

Potential.     In  electrical  parlance  equals  the  term  level  in  hydrostatics. 

Rectifier.     A  device  for  converting  an  A.  C.  into  a  D.  C.  current. 

R.     Abbreviation  of  Resistance  in  electrical  terms. 

Shunt.  A  conductor  connecting  two  points  already  in  a  circuit  through 
which  a  part  of  the  current  is  diverted. 

Stereographs.  (Coined  by  the  writer.)  A  pair  of  stereoscopic  skia- 
graphs. 

ELECTRICAL  UNITS  OF  MEASUREMENTS. 
(International  Standards.) 

The  Ampere   (French). — The  practical  unit  of  electric  current 
strength  and  equals  the  current  produced  by  pressure  of  one  Volt 


602  APPLICATION   OF   THE   ROENTGEN   RAY   TO   DENTISTRY. 

through  one  Ohm.  Equivalent  to  the  unvarying  quantity  of  current, 
which  when  passed  through  a  standard  solution  of  Silver-Nitrate  in 
water,  deposits  silver  at  the  rate  of  o.ooi  1 18  grams  per  second. 

The  Ohm  (German). — ^The  unit  of  resistance  equals  the  resistance 
of  Mercury  at  the  temperature  of  melting  ice,  14.4521  grams  in  mass, 
and  of  a  constant  cross-sectional  area,  and  106.3  centimeters  long 
(Ohm's  law  for  direct  currents  only). 

The  Volt  (Volta-Italian). — The  unit  of  electro-motive  force  (pres- 
sure) equals  the  current  which  driven  through  one  Ohm  will  produce  one 
Ampere. 

The  Coulomb  (French). — ^The  unit  of  quantity  equals  the  amount 
of  current  transferred  by  a  current  of  one  Ampere  in  one  second. 

The  Watt  (Scottish). — ^The  unit  of  electric  power  equals  the 
amount  of  work  done  by  a  direct  current  of  one  Ampere,  at  a  pressure 
of  one  Volt — 1/746  H.  P.  The  kilowatt  hour  is  the  commercial  unit 
used  for  the  electric  current  supplied  consumers,  equals  one  thousand 
watts  supplied  for  one  hour. 

The  Joule  (French). — ^Unit  of  electric  energy  equals  the  energy 
expended  in  one  second  by  the  passage  of  one  Ampere  through  one  Ohm. 

The  Farad  (Faraday). — ^The  unit  of  electric  capacity  equals  that 
capacity  which  with  one  Coulomb  gives  a  differential  of  one  Volt. 


CHAPTER  XXXIIl. 
ORTHODONTIA.* 

BY  HERBERT  A.  PULLEN,  D.  M.  D. 
PART  I. 

Orthodontia  is  that  branch  of  dental  medicine  which  treats  of  the 
etiology,  diagnosis,  and  correction  of  abnormal  development  of  the  dental 
arches,  dental  malocclusion,  and  consequent  facial  inharmony. 

Scope  of  Orthodontia. — Orthodontia  embraces  much  more  than 
the  correction  of  malpositions  of  the  teeth,  which,  in  its  earUer  history, 
was  the  Hmit  of  its  field  of  operations,  and  to-day  has  developed  into  a 
highly  specialized  science,  based  upon  rational  theory  and  practice. 

As  a  branch  of  the  healing  art,  orthodontia  deals  primarily  with  the 
normal  development  of  the  teeth  and  the  dental  arches,  but  secondarily, 
through  contiguity  of  structure  and  interrelationship  of  function,  it 
is  directly  associated  with  the  normal  development  of  the  internal  and 
external  face,  and  indirectly  with  the  functions  of  respiration,  digestion, 
and  nutrition ;  hence,  by  this  series  of  related  structures  and  functions, 
with  the  health  of  the  whole  body. 

Diagnostic  considerations  have  assumed  such  importance  as  to 
foster  and  demand  a  conception  of  the  scope  of  orthodontia,  which 
includes  as  well  an  intelligent  insight  into  causative  factors  of  abnormal 
conditions  of  growth  of  the  dental  and  maxillary  arches,  of  the  adjacent 
structures  of  the  internal  face,  the  naso-respiratory  tract,  and  also 
those  factors  which  afifect  bodily  growth  and  function  as  a  whole. 

A  more  definite  etiology,  therefore,  based  upon  general  as  well  as 
local  pathology,  has  been  established  in  orthodontia,  for  it  is  clearly 
recognized  that  the  arrest  of  growth  and  disturbance  of  function  of  the 
internal  and  external  face  associated  with  many  cases  of  malocclusion 
are  but  symptomatic  expressions  of  disturbances  of  balance  in  nutrition 
or  some  other  vital  function  of  a  general  rather  than  a  local  nature. 

Again,  many  of  the  harmonious  and  beautiful  lines  of  the  face  being 

*  The  author  gratefully  acknowledges  the  courtesies  of  the  Dental  Cosmos,  the  Items 
of  Interest,  the  Dental  Summary,  and  the  Journal  of  the  Allied  Societies  and  the  va- 
rious writers  mentioned  in  the  text  in  loaning  cuts  for  some  of  the  illustrations.  Many 
of  the  photographs  of  models  of  the  author's  cases  were  made  by  Phil.  J.  Knapp. 

603 


604  ORTHODONTIA. 

dependent  upon  the  normal  development  of  the  related  structures  and 
functions  of  the  mouth  and  nose,  the  production  of  lines  of  beauty  in 
the  face  through  the  development  of  the  dental  arches  and  the  correction 
of  malocclusion,  by  restoring  normal  balance  to  the  profile,  opens  up  a 
field  of  fascinating  interest  and  wonderful  possibility.  The  study  of 
art  in  its  relation  to  harmony  and  beauty  of  the  face  thus  becomes  a 
necessary  adjunct  to  orthodontia. 

Finally,  the  mechanical  appliances  by  which  these  restorations  of 
structure  and  function  of  the  dental  arches,  and  the  corrections  of 
inharmonious  facial  lines  are  made  possible,  call  for  a  comprehensive 
knowledge  of  the  underlying  principles  of  physics  and  mechanics,  so 
that  these  operations  may  be  conducted  along  strictly  scientific  lines, 
whereby  the  proper  standards  of  efl&ciency  in  treatment  may  be 
maintained. 

Thus  it  will  be  seen  that  the  field  of  orthodontia  is  a  broad  one, 
requiring  a  knowledge  of  the  physiological  development  of  the  dental 
arches  and  associated  structures,  the  relation  of  associated  functions, 
the  local  or  remote  etiological  characteristics  of  malocclusion,  its  proper 
classification,  diagnosis,  and  scientific  treatment  based  upon  such 
physiological  and  mechanical  principles  as  will  tend  to  restore  normal 
relations  of  the  dental  arches  and  lines  of  beauty  to  the  face,  and  such 
improvement  in  the  general  health  as  is  possible  in  the  restoration  of 
function  of  the  masticatory  and  respiratory  mechanisms. 

Trend  of  Modern  Theory  and  Practice. — Modern  orthodontia 
owes  much  of  its  impulse  and  present  scientific  trend  to  Angle,*  who, 
in  his  presentation  of  the  theory  of  normal  occlusion  in  its  relation  to 
development  of  the  dental  arches,  and  his  classification  and  treatment 
of  dental  malocclusion  from  this  basis,  gave  the  first  real  insight  into 
the  broad  field  of  study  and  investigation  of  underlying  principles  in 
medicine  and  mechanics  which  is  building  up  this  science  as  one  of  the 
most  progressive  of  modern  times. 

Since  the  recognition  of  normal  occlusion  as  the  basis  of  orthodontia, 
the  later  trend  of  orthodontic  investigation  has  dealt  with  the  earlier 
developmental  conditions  which  precede  the  attainment  of  function  of 
the  full  complement  of  teeth  in  normal  occlusion,  and  a  more  compre- 
hensive knowledge  of  the  factors  which  may  interfere  with  these  devel- 
opmental conditions  has  led  to  the  necessity  for,  and  inauguration  of, 
earlier  treatment  of  incipient  malocclusion. 

It  is  evident  that  normal  occlusion  of  the  permanent  teeth,  being  the 
culmination  of  functional  and  structural  development,  may  supervene 
*  Angle,  Malocclusion  of  the  Teeth,  6th  Ed.,  igoo. 


DEVELOPMENT  OF  THE  DENTAL  ARCHES.  605 

only  when  the  normal  growth  of  the  dental  arches  and  their  associated 
structures  occurs,  for  if  development  of  the  dental  arches  and  related 
structures  is  arrested  at  any  stage  of  growth  or  is  deficient  through  any 
cause,  abnormal  occlusal  relations  are  inevitable. 

Malpositions  of  the  teeth  in  general,  then,  may  be  considered  as  the 
objective  symptoms  of  abnormal  growth  of  the  dental  arches,  usually 
manifested  by  an  arrest  or  deficiency  in  development. 

Thus  it  is  that  the  problems  of  malocclusion  are  referred  back  to 
abnormal  developmental  conditions,  the  causes  of  which  are  often 
obscure,  because  of  their  being  involved  in  the  development  of  the 
body  as  a  whole,  in  factors  of  metabolism,  nutrition,  and  functional 
insufficiency  of  various  natures. 

This  recognition  of  the  dependence  of  normal  occlusal  relations 
upon  the  physiological  factors  involving  as  well  as  preceding  the  first 
dentition  necessitates  a  knowledge  of  the  sequence  of  certain  of  these 
developmental  processes  leading  up  to  the  eruption  of  the  permanent 
teeth  and  the  attainment  of  normal  occlusion. 

The  Arches  of  the  Temporary  Teeth. — In  order  to  have  a  logical 
and  chronological  succession  of  recorded  observation  of  facts,  it  is 
necessary  to  study  the  dental  arches  at  the  latest  period  before  the 
eruption  of  any  of  the  permanent  teeth,  at  a  time  when  the  deciduous 
teeth  are  all  in  situ,  and  certain  physiological  processes  are  about  to 
take  place  subsequent  to  the  shedding  of  these  teeth  and  their  replace- 
ment by  the  permanent  set,  these  changes,  according  to  the  degree  of 
perfection  of  their  physiological  performance,  having  much  to  do  with 
the  normal  or  abnormal  development  of  the  second  dentition. 

Many  cases  of  malocclusion  date  their  inception  back  to  the  time 
when  these  processes  are  taking  place,  and  a  proper  cognizance  of 
them  would  suggest  that  assistance  be  given  to  these  natural  processes, 
if  necessary  to  intervene,  rather  than  to  hinder  or  subvert  them  through 
ignorance  of  their  normal  function,  and  consequent  ill-advised  treat- 
ment of  certain  conditions  which  may  present. 

Fig.  449  shows  perfect  development  of  the  deciduous  dental  arch 
in  normal  occlusion,  at  the  age  of  four  years,  at  which  time  all  of  the 
deciduous  teeth  are  in  position  and  accomplishing  the  function  of 
mastication  to  the  degree  necessary  for  the  nutrition  of  a  child  of  this 
tender  age. 

The  retention  of  these  teeth  until  the  initiative  in  eruption  of  the 
permanent  successors  has  taken  place,  is  a  feature  of  great  importance 
in  its  bearing  upon  the  normal  development  of  the  arches  of  the  per- 
manent teeth,  since  the  premature  loss  of  the  deciduous  teeth  invariably 


6o6 


ORTHODONTIA. 


causes  a  retardation  of  development  of  the  maxillary  arch  which  is 
always  productive  of  a  more  or  less  serious  malocclusion  of  the  perma- 
nent teeth.  For  example,  the  premature  loss  of  any  one  of  the  decidu- 
ous teeth  is  causative  of  a  lack  of  development  in  the  region  of  the 
lost  tooth,  in  extent  according  to  its  mesio-distal  diameter  and  relative 
importance  in  the  arch. 

Directions  of  Growth  of  Dental  Arches. — As  the  deciduous 
dental  arches  increase  in  size  it  will  be  noted  that  the  growth  takes 
place  in  three  dimensions,  length,  breadth,  and  height.  Fig.  450 
illustrates  the  growth  in  height  at  six  years  of  age  over  the  growth  of  the 
same  dental  arches  at  four  years  of  age,  Fig.  449. 

The  increase  in  length  and  breadth  of  these  same  dental  arches  is 
best  observed  from  the  comparison  of  the  upper  dental  arches  placed 


Fig.  449. 


Fig.  450. 


side  by  side,  the  line  in  front  of  the  first  permanent  molars  in  Fig.  452, 
indicating  the  extent  of  development  of  the  deciduous  arch  shown  in 
Fig.  451  before  the  eruption  of  the  first  permanent  molars. 

In  two  years  of  development  the  alveolar  processes  have  grown 
downward  in  the  upper  arch,  and  upward  in  the  lower  arch,  and  the 
first  molar  teeth  have  come  into  occlusion,  holding  the  dental  arches 
the  proper  distance  apart,  affording  new  and  broad  masticating 
surfaces  for  use  during  the  shedding  of  the  deciduous  teeth,  and  by  their 
deep  cusp  interdigitation,  accentuating  the  perfect  mesio-distal  regis- 
tration of  the  dental  arches,  which  the  deciduous  teeth  initiated 

Developmental  Spaces. — While  the  deciduous  arch  still  retains 
its  full  complement  of  teeth,  between  the  fifth  and  sixth  year,  the 
coordinate  and  coincident  growth  of  maxilla  and  mandible  are  taking 


DEVELOPMENT  OF  THE  DENTAL  ARCHES. 


607 


place  not  only  in  the  forward,  downward  and  lateral  development,  but 
in  an  interstitial  growth  in  the  alveolar  process  and  maxillae,  due  to  the 
erupting  teeth,  which  is  evidenced  by  a  separation  of  the  deciduous 
incisors  as  lateral  development  progresses. 

Fig.  453  illustrates  the  arches  of  deciduous  teeth  in  occlusion  just 


Fig.  451. 


Fig.  452. 


previous  to  the  eruption  of  the  permanent  incisors  in  a  patient  six 
and  one-half  years  old,  a  case  in  which  the  anterior  development  of  the 
process  has  taken  place  normally,  as  noted  by  rhe  spacing  between  the 
deciduous  incisors.     When  the  dental  arches  present  this  appearance 


Fig.  453. 


just  prior  to  the  eruptive  period  of  the  incisors,  there  is  every  assurance 
that  the  eruption  of  the  permanent  incisors  will  occur  without  crowding. 
Occlusal  Relations  of  Temporary  Teeth.— All  of  the  laws  of 
occlusion  which  pertain  to  the  preservation  of  the  integrity  of  the 
permanent  arches  of  teeth  are  in  evidence  in  a  lesser  degree  in  the 


6o8  ORTHODONTIA. 

arches  of  deciduous  teeth,  both  as  to  the  interdependence  of  one  arch 
upon  the  other  for  the  preservation  of  form  through  normal  cusp  inter- 
digitation,  and  as  to  the  normal  growth  dependent  upon  functional 
activity. 

It  vi^ill  be  observed  in  the  study  of  the  normal  deciduous  dental  arches 
that  there  is  a  slight  overbite  in  the  incisor  region,  Fig.  449,  and  that 
each  upper  central  incisor  overlaps  the  labial  surface  of  the  lower  central 
and  one-half  of  the  lateral  incisor;  each  upper  lateral  incisor  overlap- 
ping the  distal  half  of  the  labial  surface  of  the  lower  lateral  incisor, 
and  the  mesial  incline  of  the  lower  cuspid.  The  antero-posterior  in- 
terdigitation  of  the  cusps  of  the  cuspids,  and  first  and  second  deciduous 
molars  is  likewise  conformative  to  a  normal  occlusion  and  arrangement. 

The  normal  occlusal  relation  of  the  arches  of  the  deciduous  teeth 
is  a  very  important  factor,  through  the  exercise  of  normal  function,  in 
the  normal  development  of  the  permanent  dental  arches,  the  osseous 
structures  in  which  they  are  imbedded,  and  in  the  production  of 
normal  occlusion  of  the  permanent  teeth. 

The  growth  of  the  osseous  structures  which  surround  the  teeth  of 
both  the  deciduous  and  permanent  dentures  is  directly  dependent  upon 
their  functional  efficiency.  Quoting  from  Noyes*  "Bone  is  formed 
and  reformed  in  response  to  mechanical  stimuli,  and  the  entire  surface 
is  arranged  in  harmony  with  the  mechanical  stresses  which  result  from 
the  forces  applied  to  the  teeth  and  the  surface  of  the  bone^  "The  adult 
maxillary  bones,  which  are  such  important  factors  in  the  beauty  and 
harmony  of  the  face,  are  the  result  of  the  sum  total  of  all  of  the  forces 
acting  upon  them." 

Thus  it  is  that  the  dental  arches,  the  maxillary  bones,  and  to  a 
certain  extent  their  associated  anatomical  structures  are  built  up  and 
supported.  The  function  of  occlusion  in  the  deciduous  teeth,  then, 
plays  an  important  role  in  the  development  of  the  internal  and  external 
face.  The  associated  functions  of  respiration  and  even  of  deglutition, f 
and  of  the  muscles  of  the  face  have  equally  an  important  role  to  play  in 
the  harmonious  development  of  the  structures  involving  the  dental 
arches.  The  further  factors  in  development  of  the  dental  arches  and 
their  surrounding  osseous  structures  are  those  that  relate  to  bodily 
development  as  a  whole,  such  as  nutrition,  metabolism,  etc. 

Transition  Period  of  Occlusion. — ^The  eruption  to  occlusion  of  the 
first  permanent  molars,  Fig.  450,  marks  the  transition  stage  from  the 
deciduous  to  the  permanent  dentition,  initiating  a  period  of  dental 

*Noyes,  The  Alveolar  Process.     The  American  Orthodontist,  May,  iqo8. 
fNoyes,  The  Machine  and  the  Power,  Journal  of  the  Allied  Societies,  June,  1914. 


DEVELOPMENT  OF  THE  DENTAL  ARCHES. 


609 


arch  development  of  much  greater  extent  than  that  of  the  deciduous 
dentition,  and  commensurate  with  the  more  complete  and  pronounced 
function  of  occlusion  of  the  permanent  teeth,  and  proportionate  to  the 
development  of  the  face  as  a  whole.  The  first  permanent  molars, 
erupting  distally  to  the  deciduous  molars  (Fig.  454),  have  a  function 
to  perform  in  establishing  the  normal  relationship  between  the  dental 
arches  during  the  interval  of  shedding  of  the  temporary  teeth,  as  well 
as  providing  the  broadest  and  best  masticating  surfaces  in  the  mouth 
during  this  period.  Also,  as  Noyes  describes  them,  "the  locking  of 
their  cusps  determines  the  balance  of  physiological  forces  as  distributed 
upon  the  mandible,"  referring  to  "the  fulcrum  upon  which  the  activity 
of  the>,'muscles  attached  to  the  ramus  and  the  posterior  part  of  the 


Fig.  454.  {Noyes.) 

mandible,  and  those  attached  to  the  anterior  portion  of  the  man- 
dible, are  balanced." 

Occlusal  Relations  of  Permanent  Teeth.— The  fulfillment  of 
natural  or  normal  development  in  the  dental  and  maxillary  arches  in 
the  completed  dentition  constitutes  a  normal  and  ideal  relationship 
of  occlusion  of  the  teeth  from  which  it  is  possible  to  note  deviations  in 
malocclusion,  and  a  guide  for  comparison  in  the  restoration  of  normal 
conditions,  viz.,  normal  occlusion. 

The  characteristics  of  this  normal  dental  and  maxillary  develop- 
ment, including  the  normal  development  of  adjacent  structures,  are 
39 


6lO  ORTHODONTIA. 

necessarily  specified  and  limited,  and  may  be  comprehended  in  the 
following  definition. 

Normal  Occlusion  is  a  condition  of  perfect  relationship  existing  be- 
tween the  normally  formed  and  arranged  teeth  of  normally  developed  den- 
tal arches  when  in  antagonism,  the  mandible  being  in  its  farthest  posterior 
position,  and  in  exact  median  register  with  the  maxilla,  and  both  in 
normal  relationship  with  contiguous  tissues. 


Fig   455.     (Broomell.) 

Normal  occlusion,  in  the  ideal,  is  seldom  found  in  any  type  of  in- 
dividual, although  the  approximation  of  it  in  many  cases  varies  but 
little  from  the  ideal  anatomical  occlusion. 

In  all  branches  of  art,  such  as  sculpture,  painting,  architecture,  etc., 
a  model  of  p)erfect  art  is  chosen  as  a  guide  to  reproductions  which  rep- 
resent the  highest  conceptions  of  a  certain  type,  whether  it  be  the 
Apollo  in  sculpture,  the  Madonna  in  painting,  or  the  Renaissance  in 


DEVELOPMENT  OF  THE  DENTAL  ARCHES.  6ll 

architecture.  Normal  occlusion  is  the  highest  conception  of  a  type, 
not  a  relative  or  approximate  condition.  It  is  an  ideal  state  of  physical 
integrity,  and  can  only  be  perfectly  conceived  in  a  perfect  anatomical 
subject,  which  would  necessitate,  therefore,  the  normal,  typical,  and 
perfect  development  and  relationship  of  contiguous  tissues  of  the  osse- 
ous and  muscular  tissues  of  the  head  and  face,  and  the  harmonious 
and  proportionate  development  of  the  facial  lines  which  are  conforma- 
tive  to  beauty  and  harmony  of  the  profile. 

It  has  been  suggested  that  the  word  "occlusion"  alone  be  used 
to  designate  this  ideal  relationship;  that  the  word  "normal"  is  un- 
necessary, since  if  occlusion  is  anything,  it  is  normal;  otherwise,  maloc- 
clusion is  the  proper  term,  but  the  acceptance  of  this  term  without  the 
limiting  characteristic  which  the  word  "normal"  adds  to  it  would  be 
confusing  and  unwarrantable  in  referring  to  the  typically  ideal  anatom- 
ical occlusion. 

The  commonly  accepted  use  of  "occlusion"  is  in  reference  to  the 
relation  of  the  interdigitating  cusps  of  the  teeth,  whether  there  is  a 
normal,  or  a  malocclusion  present,  and  it  may  be  definitely  described 
as  follows: 

Occlusion  is  the  most  constant  static  relationship  of  the  antagonizing 
surjaces  of  the  arches  of  teeth  in  inter digitation. 

A  Malocclusion  is  any  variation  from  a  normal  occlusion  either  in 
size,  shape  or  relation  of  dental  arches,  or  perversion  oj  inclined  cusp 
planes. 

The  following  relations  of  occlusion  of  the  permanent  teeth  are 
based  upon  the  description  of  normal  occlusion  by  Angle. 

Characteristics  of  Normal  Occlusion. — Fig.  455  exhibits  a  skull 
in  which  normal  occlusion  is  present,  and  in  which  the  following 
characteristics  may  be  noted: 

1.  The  normal  shape  and  size  (according  to  type)  of  each  arch. 

2.  The  normal  position  of  each  tooth  in  each  arch. 

3.  The  normal  shape  and  size  of  each  tooth  (varying  with  type)  in 
each  arch. 

4.  The  normal  relationship  of  each  arch  to  the  other,  and  of  the 
occlusal  inclined  planes  of  the  cusps  of  the  teeth  in  one  arch  to  those  of 
the  other. 

The  bilateral  arrangement  of  the  muscles,  the  shape  of  the  arches 
of  teeth,  and  their  harmonious  relation  to  each  other;  the  form,  size, 
and  position  of  the  teeth  with  their  cusps  interdigitating  for  mutual 
support,  the  proximal  contact,  the  upward  curve  of  the  ramus,  and  the 
relations  of  the  occlusal  planes,  all  serve  the  purpoes  of  increasing  the 


6l2  ORTHODONTIA. 

efficiency  of  the  organs  of  mastication,  by  providing  the  means  whereby 
a  co-ordination  and  equilibrium  of  forces  are  secured,  which  are 
essential  for  the  preservation  and  function  of  the  organs  themselves, 
as  well  as  for  economy  of  force,  and  the  production  of  lines  of  beauty 
not  possible  in  any  other  arrangement. 

In  examining  the  interdigitation  of  the  teeth  upon  each  lateral 
half,  it  will  be  seen  that  each  tooth  has  two  antagonists  in  the  opposite 
arch,  except  the  lower  central  incisor  and  upper  third  molar;  tnis 
arrangement  not  only  providing  the  greatest  support  for  the  teeth 
individually  and  collectively,  but  also  allowing  the  inclined  planes  of 
the  cusps  of  bicuspids  and  molars  the  best  opportunity  for  articulating 
during  the  lateral  excursions  of  the  mandible. 

Relations  of  Inclined  Cusp  Planes. — Beginning  at  the  median 
line  of  the  dental  arches  in  normal  occlusion,  the  following  cusp  rela- 
tions which  are  conformative  to  the  normal  in  the  bucco-occlusal 
relations  of  the  teeth  may  be  noted.  The  upper  central  incisor  is 
in  occlusal  contact  with  the  incisal  edges  of  the  lower  central  in- 
cisor and  one-third  to  one-half  of  the  lower  lateral  incisor;  the  upper 
lateral  incisor  is  in  occlusal  contact  with  the  remaining  two-thirds 
or  one-half  of  the  incisal  edge  of  the  lower  lateral  incisor,  and  the 
mesio-incisal  angle  of  the  lower  cuspid;  the  upper  cuspid  occludes  with 
its  mesial  incline  in  contact  with  the  distal  incline  of  the  lower  cuspid, 
and  its  distal  incline  in  contact  with  the  mesial  incline  of  the  buccal  cusp 
of  the  lower  first  bicuspid;  the  buccal  cusp  of  the  upper  first  bicuspid 
occludes  with  its  mesial  incline  in  contact  with  the  distal  incline  of 
the  buccal  cusp  of  the  lower  first  bicuspid,  and  its  distal  incline  in  con- 
tact with  the  mesial  incline  of  the  buccal  cusp  of  the  lower  second 
bicuspid;  the  buccal  cusp  of  the  upper  second  bicuspid  occludes  with 
its  mesial  incline  in  contact  with  the  distal  incline  of  the  buccal  cusp  of 
the  lower  second  bicuspid,  and  its  distal  incline  in  contact  with  the 
mesial  incline  of  the  mesio-buccal  cusp  of  the  lower  first  molar;  the 
mesial  inclines  of  the  mesio-  and  disto-buccal  cusps  of  the  upper  first 
molar  occlude  with  the  distal  inclines  of  the  mesio-  and  disto-buccal 
cusps  of  the  lower  first  molar;  the  distal  incline  of  the  disto-buccal  cusp 
comes  into  occlusal  contact  with  the  mesial  incline  of  the  mesio-buccal 
cusp  of  the  lower  second  molar;  similar  relations  of  the  inclined  cusp 
planes  are  in  evidence  in  the  second  and  third  molars,  except  that  the 
upper  third  molar  has  no  antagonizing  plane  for  the  distal  incline  of 
its  disto-buccal  cusp.  A  similar  arrangement  of  the  lingual  cusps  of 
the  upper  teeth  in  their  occlusal  relations  with  the  lower  renders  the 
interdigitation  of  cusps  for  mutual  support  still  more  pronounced. 


DEVELOPMENT  OF  THE  DENTAL  ARCHES.  613 

The  object  of  this  complex  interdigitation  of  cusps  is  to  give  the 
greatest  support,  not  only  to  the  teeth  individually,  but  as  a  whole, 
their  sizes,  forms  and  positions  of  cusps  and  inclined  planes  being  best 
adapted  for  this  purpose. 

Preservative  Forces  of  Normal  Occlusion.— Having  outlined 
the  positions  of  the  individual  teeth  in  normal  occlusion,  it  is  quite 
important  that  cognizance  be  taken  of  the  forces  which  tend  to  pre- 
serve this  normal  arrangement,  viz.: 

1.  The  interdigitation  of  the  cusps  of  the  teeth. 

2.  The  reaction  and  dependence  of  one  arch  upon  the  other. 

3.  The  proximate  contact. 

•  4.  The;  muscular  influence  of  the  lips,  cheeks,  and  tongue,  labially, 
buccally  and  lingually. 

As  one  arch  is  dependent  upon  the  other  for  its  regularity,  it  follows 
that  a  malocclusion  in  one  arch  implies  a  similar  condition  in  the  other, 
and  the  maintenance  of  the  malocclusion  is  just  as  effectual  as  the 
maintenance  of  a  normal  occlusion  through  the  normal  influence  of 
the  above-mentioned  forces.  If  the  lower  arch  is  contracted  and  the 
teeth  crowded,  the  same  conditions  will  be  found  in  the  upper  arch  as 
a  result  of  the  operation  of  these  forces. 

Distinction  between  Occlusion  and  Articulation. — ^The  syn- 
onymous use  of  the  terms  "occlusion"  and  "articulation"  is  not  in 
accordance  with  their  specifically  different  meanings,  as  generally  un- 
derstood by  those  who  have  carefully  studied  them. 

Articulation  is  the  relation  between  the  antagonizing  surfaces  of  the 
teeth  of  maxilla  and  mandible  during  the  lateral  and  protrusive  excursions 
of  the  latter,  dependent  upon  its  universal  articulation  at  the  glenoid  fossa. 

There  are  three  distinct  stages  of  articulation,  viz.,  incision,  attrition, 
and  occlusion.  The  first  two  stages  represent  the  mandible  in  motion; 
the  last,  the  mandible  at  rest,  the  teeth  being  closed. 

Occlusion  is  the  passive  phase  of  articulation,  as  compared  to  the 
active  phases  of  incision  and  attrition.  Occlusion  represents  the  static, 
and  articulation  the  dynamic,  relation  between  the  arches  of  teeth. 

Some  writers  have  argued  that  occlusion  should  represent  all  that 
is  meant  by  articulation  in  its  relation  to  orthodontia,  but  such  a  gen- 
eralization of  the  term  would  be  absurd,  and  any  attempts  at  diagnosis 
of  malocclusion  from  such  a  variable  base  would  only  result  in  con- 
fusion. However,  it  is  impossible  to  completely  separate  these  terms 
in  their  bearing  upon  the  normal  relationship  of  the  arches  of  teeth, 
so  intimately  are  they  connected.     A  normal  occlusion  necessitates  a 


6 14  ORTHODONTIA. 

normal  articulation,  and  a  normal  articulation  necessitates  a  normal 
occlusion. 

The  laws  of  articulation  produced  the  perfectly  formed  arches  of 
teeth,  the  depth  of  the  overbite,  the  length  of  cusps,  and  relations  of 
occlusal  inclined  planes,  so  that  the  definite  form  and  positions  of  the 
teeth  and  relations  of  the  arches  known  as  normal  occlusion  was  a  pos- 
sibility. In  occlusion,  the  lines  of  force  are  constant  in  their  direction; 
in  articulation,  they  are  ever  changing,  varying  as  the  relationship  be- 
tween the  arches  of  teeth  causes  stress  to  be  made  between  antagonizing 
tooth  surfaces  in  constantly  changing  angles. 

Relation  between  Overbite  and  Length  of  Tooth  Cusps. --By 
carefully  studying  the  forms  and  positions  of  the  inclined  planes  of 
the  cusps  of  the  individual  teeth,  the  length  of  cusps,  decreasing  in 
depth  from  the  first  bicuspid  to  the  last  molar,  the  depth  of  the  overbite, 
and  the  "compensating  curve"  of  the  arches,  it  will  be  noticed  that  there 
is  a  distinct  relationship  existing  between  the  length  of  the  cusps  m 
bicuspids  and  molars,  and  the  overbite,  and  the  "compensating  curve," 
as  pointed  out  by  Bonwill.  .  For  example,  in  cases  in  which  the  overbite 
of  the  incisors  is  long,  the  length  of  the  cusps  of  the  bicuspids  and  molars 
is  also  long,  and  in  cases  of  short  incisor  overbite,  the  length  of  the 
bicuspid  and  molar  cusps  is  correspondingly  short.  This  is  typical 
of  the  usual  denture  although  cases  have  been  observed  showing  that 
this  relation  was  not  constant.  Turner*  illustrates  a  case  of  this  kind 
where  there  is  a  disproportion  between  cusp  length  and  overbite. 

The  Curve  of  Spee. — ^The  so-called  "compensating  curve,"  or 
curve  of  Spee,f  bears  such  an  important  relation  to  the  length  of  cusps 
and  overbite  that  a  brief  description  of  it  will  aid  in  its  understanding. 
The  curve  of  Spee  is  the  segment  of  a  circle,  the  path  of  the  arc  of  which 
touches  the  edges  of  the  lower  incisors,  the  point  of  the  lower  cuspid 
and  the  tips  of  the  buccal  cusps  of  the  lower  bicuspids  and  molars,  and 
passes  either  anteriorly  or  posteriorly  to  the  articular  face  of  the 
condyloid  process  (Fig.  456). 

In  the  relation  existing  between  the  length  of  molar  and  bicuspid 
cusps,  the  overbite,  and  the  "  compensating  curve,"  or  "  Curve  of  Spee," 
the  radius  of  the  circle  on  which  this  curve  is  superinscribed  is  longer 
or  shorter  in  direct  proportion  to  the  length  of  the  cusps  and  the 
depth  of  the  overbite,  i.e.,  a  long  or  deep  overbite  indicates  a  curve  of 
Spee  inscribed  on  the  circumference  of  a  circle  with  a  short  radius, 

*  Chas.  W.  Turner,  The  Human  Dental  Mechanism,  page  220,  Fig.  197. 
t  Described  by  F.  Graf  V.  Spee. 


DEVELOPMENT  OF  THE  DENTAL  ARCHES.  6lS 

and  vice  versa.  Also,  this  radius  is  shortest  in  those  cases  in  which 
the  angle  of  inclination  of  the  glenoid  fossa  is  the  greatest,  and  longer 
in  proportion  to  the  approach  of  the  angle  of  inclination  of  the  glenoid 
fossa,  and  hence  the  path  of  the  condyles. to  the  horizontal. 

The  abnormal  variation  of  the  "curve  of  Spee"  in  certain  types  of 
malocclusion  is  sufficient  evidence  of  the  importance  of  giving  it  due 


Fig.  456. 

consideration  in  the  diagnosis  and  treatment  of  malocclusion,  cases 
of  which  will  be  later  described. 

INormal  Development  of  Associated  Anatomical  Structures  of 
the  Internal  Face. — In  order  that  a  clearer  idea  of  the  field  of  the 
orthodontist  may  be  engendered,  a  study  of  the  internal  facial  anatomy- 
from  a  vertical  transverse  bilateral  section  of  the  head,  as  shown  in 
one  of  Dr.  Cryer's  dissections,  Fig.  457,  revealing  comparatively 
normal  development  of  the  maxillary  arches  and  associated  structures 
and  sinuses,  may  serve  to  illustrate  how  closely  the  internal  structures 
are  associated,  and  to  what  extent  they  are  interdependent  for  normal 
growth  and  function. 

Immediately  above  the  floor  of  the  hard  palate  may  be  observed  a 
straight  nasal  septum,  dividing  the  internal  nose  into  two  large  and 
well  formed  meati,  adjacent  to  which,  the  fully  developed  maxillary 
sinuses  are  situated. 

This  normal  and  proportionate  development  of  associated  anatom- 
ical structures  of  the  internal  face  is  not  a  chance  coincidence,  but  the 
result  of  a  functional  and  structural  relationship  which  is  most  im- 
portant to  the  diagnostician. 

First  in  importance  in  the  development  of  these  associated  struc- 
tiu^es  of  the  mouth  and  nose  is  the  function  of  mastication,  the  natural 
action  and  reaction  of  the  teeth  of  the  mandible  against  those  of 
the  maxilla  assisting  in  the  development  of  the  dental  and  maxillary 


6i6 


ORTHODONTIA. 


arches,  and  thereby  in  the  development  of  the  floor  of  the  nose  and 
associated  sinuses  etc. 

Second  in  importance  in  the  development  of  the  dental  and  maxil- 
laryarches  is  the  function  of  normal  nasal  breathing,  which  is  only 
possible  with  properly  developed  nasal  meati. 

Abnormal  breathing  disturbs  normal  developmental  functions,  be- 
cause with  deficient  respiratory  powers,  as  in  the  mouth-breather,  the 


Fig.  457.     {Cryer.) 


teeth  seldom  come  into  contact  sufficiently  to  obtain  the  requisite 
amount  of  occlusion  and  articulation  necessary  for  proper  development 
of  the  arches. 

Co-ordination  of  Functions. — It  will  be  apparent,  therefore,  that 
co-ordination  of  the  normal  functions  of  respiration  and  occlusion  is 
the  most  potent  factor  in  the  symmetrical  and  proportionate  develop- 
ment of  the  internal  face,  the  nasal  cavities  and  associated  sinuses,  and 
the  maxillary  and  dental  arches. 

Such  symmetrical  development  of  related  parts  implies  as  well  the 
existence  of  full  nutrition,  and  the  absence  of  any  untoward  etiological 


SYMMETRY   AND    ASYMMETRY    OF   THE    FACE.  617 

factors  which  would  tend  to  diminish  functional  influence  or  lower 
the  vitality  in  any  way. 

Any  local  functional  and  developmental  disturbance  may  be  the 
result  of  general  systemic  conditions,  of  lowered  vitality  from  what- 
ever cause,  so  that  any  local  pathological  manifestation  in  diminished 
or  perverted  function  and  consequent  modified  anatomical  structures 
should  be  considered  in  relation  to  the  health  of  the  whole  organism. 

The  association  of  nasal  stenosis,  mouth-breathing,  arrested  de- 
velopment of  the  maxillae,  and  dental  malocclusion,  is  sufficient  evi- 
dence of  the  interdependence  of  function  and  structure  in  these  associ- 
ated regions  to  convince  the  most  skeptical  of  the  importance  of  the 
study  of  the  pathological  anatomy  of  the  internal  face  with  a  view  to 
the  discovery  of  certain  causative  factors,  which  through  treatment  will 
assist  in  the  remedy  or  cure  of  abnormal  developmental  conditions 
requiring  an  intelligent  differential  diagnosis. 

It  is  primarily,  then,  upon  the  structural  continuity  of  the  maxillary 
arches  with  the  structures  of  the  nose,  and  upon  the  contiguity  of  the 
internal  sinuses,  as  well  as  upon  the  correlation  of  the  functions  of 
occlusion  and  respiration,  that  the  possibility  of  influencing  develop- 
ment and  restoring  function  in  these  correlated  parts  of  the  face  is 
based.  These  several  relationships  will  be  further  considered  in  the 
chapter  on  etiology. 

PART  II. 
SYMMETRY  AND  ASYMMETRY  OF  THE  FACE. 

Dento-facial  Orthopedia.* — Orthodontia  has  advanced  beyond 
the  teachings  which  its  name  might  imply  into  the  field  of  orthopedia  to 
such  an  extent  that  there  can  scarcely  be  any  orthodontic  treatment 
which  does  not  include  orthopedic  considerations.  The  restoration  of 
esthetic  facial  contour  through  orthodontic  and  orthopedic  treatment, 
although  included  in  the  field  of  orthodontia,  may  correctly  be  desig- 
nated dento-facial  orthopedia,  and  be  defined  as  follows: 

Dento-facial  Orthopedia  is  the  art  of  restoration  of  facial  sym- 
metry through  the  correction  of  abnormal  development  of  the  dental  and 
maxillary  arches,  and  dental  malocclusion. 

Physical  Relations  of  Beauty. — The  broadening  of  the  field  of 
orthodontia  to  embrace  the  field  of  facial  orthopedia  has  necessitated  a 
closer  study  of  the  art  relations  of  the  human  face  with  a  view  of  ascer- 
taining those  qualities  of  beauty  which  are  related  to  the  normal  and 

*  Term  coined  by  Desirabode. 


6l8  ORTHODONTIA. 

typical  in  development,  rather  than  those  qualities  of  facial  beauty 
which  appeal  to  the  esthetic  faculties  alone. 

Beauty  is  defined  as  "the  assemblage  of  graces  or  properties  which 
are  pleasing  to  the  eye,  the  ear,  the  intellect,  the  esthetic  faculty,  or 
the  moral  sense,"  or  as  "the  multiplicity  of  symmetrical  parts  uniting 
in  a  consistent  whole." 

It  has  been  pointed  out  by  artists  that  no  fixed  "line  of  harmony" 
exists  in  relation  to  the  profile,  but  that  beauty  of  the  face  consists  in  a 
proper  balance  of  the  features  according  to  type. 

Limited,  then,  as  the  science  of  orthodontia  is,  to  a  consideration  of 
the  physical  relations  of  certain  definite  parts  of  the  face,  the  qualities 
of  symmetry  and  proportion  alone,  as  indicated  by  the  normal  and 
harmonious  development  of  the  face  as  a  whole,  including  the  under- 
lying osseous  structures  as  well  as  the  muscular  tissues  overlying 
them,  can  be  consistently  studied  in  the  determination  of  the  normal  or 
abnormal  relations  of  these  structures. 

Facial  Types. — The  facial  orthopedist  should  never  lose  sight  of 
the  fact  that  there  are  a  great  many  types  of  faces,  varying  with 
nationality,  climate  and  environment,  and  that  the  features  con- 
form with  great  persistency  to  racial  characteristics  in  particular. 

Area  of  Dento-facial  Inharmony. — ^The  area  of  dento-facial 
inharmony  is  chiefly  included  in  the  zone  of  the  lower  third  of  the  face 
(Fig.  458),  extending  a  slight  distance  above  the  lower  border  of  the 

nasal  cartilage  (a)  to  the  bottom  of  the  chin 
/  {b),    and    from    this   point   to  the  external 

ear  {h). 

feIn  the  simpler  cases  of  malocclusion  asso- 
(0\  ciated  with  facial  asymmetry  the  area  of 
^w;^  facial  inharmony  is  included  between  the 
J  horizontal   lines  ce  and  df,  as  in  cases  of  a 

\  slight  arrest  of  full  development  of  the  dental 

.jk       arches.     Some  of  the  more  complex  cases  of 
mesial,  distal,  supra-,  and  infra-occlusion  in- 

FiG.  458.  '  '       r       ' 

volve  not  only  this  area  but  also  the  zone  m- 
cluded  in  the  triangle  abh.  The  distance  from  the  nose  to  the  symphysis 
of  the  chin  in  some  cases  is  often  less  than  normal  and  infrequently 
greater  than  normal.  For  example,  in  Fig.  459  this  distance  is  less  than 
it  should  be  normally  because  of  the  infra-occlusion  of  the  molars  and 
bicuspids,  as  is  frequently  the  case  in  this  type  of  dento-facial  de- 
formity. In  Fig,  460  on  account  of  the  loss  of  a  number  of  the  teeth  by 
extraction  the  distance  from  the  nose  to  the  chin  is  less  than  normal. 


SYMMETRY   AND    ASYMMETRY    OF   THE    FACE 


619 


In  Fig.  461  the  distance  from  the  nose  to  the  point  of  the  chin  is 
abnormally  long,  due  to  abnormal  development  of  the  mandible  in 
connection  with  infra-occlusion  of  the  incisors,  cuspids  and  bicuspids. 

In  some  instances,  the  abnormal  development  of  the  mandible  has 
been  so  great  that  orthodontic  treatment  is  barely  practicable,  and 
operative  surgery  of  doubtful  benefit.  A  case  of  this  nature  is  shown  in 
Fig.  462. 


-Fig.  459. 


Fig.  460. 


Facial  Symmetry  consists  of  the  normal  and  proportionate  develop- 
ment of  facial  contour  primarily  dependent  upon  the  corresponding  develop- 
ment and  function  of  the  underlying  osseous  structures  and  sinuses. 

Symmetrical  Measurements  of  the  Facial  Profile. — ^Viewed  from 
the  standpoint  of  the  artist,  the  harmony  of  proportions  of  the  profile 
consists  in  a  balance  of  the  features  as  shown  by  a  correspondence 
in  measurement  of  prominent  divisions  of  the  profile  from  the  top  of  the 
head  to  the  chin;  from  the  hair  to  the  bottom  of  the  chin  should  measure 


\ 


^ 


Fig.  461 


Fig.  462. 


three-quarters  of  the  height  of  the  whole  head;  the  forehead  to  the  root 
of  the  nose  measures  one-fourth;  the  nose  one-fourth,  and  the  mouth 
and  chin  one-fourth.  A  very  comprehensive  illustration  of  these 
measurements  may  be  seen  in  Fig.  463,  in  which  at  the  same  time  may 
be  noted  the  correspondence  of  the  facial  curves  of  the  forehead,  nose 
and  chin,  and  the  normal  development  of  each  separate  third  of  the 
face  so  that  a  proper  balance  of  the  face  as  a  whole  is  attained. 


620 


ORTHODONTIA. 


Fig  463. 


Fig.  464. 


For  the  full  development  of  the  lower  two-thirds  of  the  face,  there 
must  not  only  be  perfect  function  in  the  respiratory  mechanism,  result- 
ing in  normal  nasal  breathing  and  development  of  the  whole  middle 
third  of  the  face,  but  there  must  also  be  proper  functional  activity  in 
mastication,  and  the  absence  of  any  untoward  influence  in  tooth  or 
arch  development.  In  Fig.  464  the  models  of  the  teeth  of  the  young 
lady,  whose  profile  is  shown  in  Fig.  463,  exhibit  likewise  a  conforma- 
tion to  the  normal  in  occlusal  relations  and  development  of  the  dental 
arches  as  might  be  expected  in  a  profile  as  well  balanced. 

A  very  well-proportioned  profile  with  a  correspondence  of  curves 
of  the  forehead,  nose,  lips  and  chin,  is  illustrated  in  Fig.  465.  Accord- 
ing to  the  principles  of  facial  symmetry,  it  would  be  expected  that 


SYMMETRY   AND    ASYMMETRY    OF    THE   FACE. 


621 


the  functions  of  respiration  and  mastication  were  unimpaired  in  this, 
individual  in  order  to  have  produced  the  correlation  of  symmetrical 
parts  of  the  profile  as  seen  in  the  illustration. 

The  middle  third  of  the  face  is  well  developed,  the  nostril  wide 
and  dilated,  and  there  was  no  indication  upon  examination  of  any 
nasal  obstruction  or  inflammation  which  might  induce  a  diminution 
of  the  normal  breathing  function. 

The  proportions  of  the  lower  third  of  the  face  are  also  so  perfect 
that  the  diagnosis  of  almost  perfect  development  of  the  arches  of  teeth 
and  the  absence  of  any  marked  malocclusion  might  be  made  with  a 
degree  of  certainty,  and  upon  examination  of  the  model  of  the  mouth  in 


Fig.  465. 


Fig.  466. 


Fig.  466,  the  correctness  of  this  diagnosis  may  be  seen,  there  being  but 
very  slight  deviation  from  the  normal  relationship  of  occlusion. 

The  observance  of  this  interrelationship  between  normally  de- 
veloped dental  arches  and  well-balanced  profiles  led  to  the  estab- 
lishment of  the  following  principle  in  orthodontia,  "the  best  balance, 
the  best  harmony,  the  best  proportions  of  the  mouth  in  its  relations 
to  the  other  features  require  that  there  shall  be  the  full  complement  of 
teeth,  and  that  each  tooth  shall  be  made  to  occupy  its  normal  position 
— normal  occlusion"  (Angle). 

Relations  of  External  and  Internal  Anatomy. — A  very  in- 
teresting illustration  of  the  relation  of  external  and  internal  facial 
development  may  be  observed  in  a  sagittal  section  of  a  typical  skull, 
Fig.  467,  made  by  Cryer.     The  profile  appears  proportionate  in  the 


622 


ORTHODONTIA. 


development  of  its  various  divisions,  and  a  vievi^  of  the  internal  anatomy 
reveals  well-developed  osseous  structures  and  sinuses  in  the  middle 
third  of  the  face,  and  a  typically  normal  development  of  the  maxilla  and 
mandible,  and  a  tongue  which  almost  completely  fills  the  oral  cavity. 
Cryer  has  demonstrated  by  many  sections  of  the  frozen  heads  of 


l-lG.  467.      {Cryer.) 

cadavers  that  variation  of  the  internal  anatomy  of  the  face  and  head 
is  of  such  frequent  occurrence  that  typical  and  syirmetrical  develop- 
ment of  the  corresponding  osseous  structures  and  sinuses  of  the  two 
lateral  halves  of  the  head  is  the  exception  rather  than  the  rule,  thus 
accounting  in  part  for  such  distinctly  noticeable  variation  in  develop- 
ment of  the  superficial  muscular  and  other  tissues. 


SYMMETRY  AND  ASYMMETRY  OF  THE  FACE. 


623 


Facial  Asymmetry  consists  of  the  abnormal  and  disproportionate 
development  of  the  contour  of  the  face,  dependent  primarily  upon  a  cor- 
responding abnormal  development  and  growth  of  the  underlying  osseous 
structures  and  sinuses. 

In  the  consideration  of  facia!  asymmetry,  as  related  to  dental  arch 
development,  it  is  necessary  to  exclude  the  facial  defects  caused  by 
such  nen^ous  lesions  as  paralysis,  or  the  structural  lesions  of  tumors, 
and  other  similar  pathological  manifestations  not  bearing  directly 
upon  the  general  laws  of  facial  development,  except  such  develop- 
mental neuroses  as  are  admitted  to  be  embryonic  in  character,  and 
which,  whether  degenerative  or  not,  must  be  taken  into  consideration 
by  the  diagnostician  of  structural  deformities  in  any  part  of  the  body. 
Measurement  of  Facial  Asymmetry. — ^The  screen  method  of 
measuring  the  face,  illustrated  in  Fig.  468,  affords  a  means  of  de- 
termining the  variations  in  height  of  the  corresponding  halves  of  the 
face,  and  also  the  variation  from  symmetry  of  the  facial  thirds,  and  the 
anatomical  deviation  from  the  central  facial  line.  In  this  illustration 
the  right  eye  and  ear  are  observed  to  be  considerably  lower  than  the 
left  eye  and  ear,  and  the  central  line  of  the  chin  does  not  coincide  with 
the  central  line  of  the  rest  of  the  face. 

Inharmony  of  the  Profile. — A 
face  may  be  perfect  in  its  type  ex- 
cept for  some  slight  deformity  in  the 
lower  third  which  may  exhibit  lack 
of  harmonious  development. 

For  example,  in  Fig.  469,  the 
profile  conforms  in  most  of  its  lines 
to  its  type,  and  contains  many  of  the 
elements  of  beauty  in  some  of  its 
proportions,  but  the  apparent  promi- 
nence of  the  lower  lip  offsets  all  the 
esthetic  characteristics  of  the  other 
parts  of  the  face.  A  study  of  this 
profile  will  convince  the  careful  ob- 
server that  the  apparent  deformity  or 
protrusion  of  the  lower  lip  and  of 
the  mandible  is  an  optical  illusion, 
and  that  the  upper  lip  alone  is  out  of 
harmony  with  the  rest  of  the  profile,  being  retruded  from  the  normal 
pose  which  it  should  occupy. 

As  proof  of  this  diagnosis,  a  study  of  the  occlusal  relations  of  the 


Fig.  468.     (Parke  Lewis.) 


264 


ORTHODONTIA. 


arches  of  teeth  in  Fig.  474  exhibits  a  normal  relationship  in  the  molar 
region,  and  an  abnormal  position  of  the  upper  anterior  teeth  alone, 
they  being  in  lingual  occlusion. 


Fig.  469. 

Deformities  of  this  nature  often  affect  the  welfare  and  happiness 
of  the  unfortunate  possessors  for  a  whole  lifetime,  so  keenly  sensitive 


Fig.  470. 


are  they  to  public  notice  and  unfavorable  comment  by  those  with  whom 
they  come  into  daily  contact. 

Any  variation  from  normal  and  symmetrical  development  of  the 
two  sides  of  the  face  may  be  detected  by  the  use  of  the  measuring  screen 


ETIOLOGY. 


625 


or  by  drawing  an  imaginary  line  through  the  center  of  the  face  from  the 
forehead  to  the  chin,  as  in  Fig.  471,  in  which  a  marked  deviation  from 
this  line  is  noticed  in  the  lower  third  of  the  face,  and  caused  by  the 
malocclusion  of  the  teeth,  which  forced  the  mandible  to  one  side. 

An  examination  of  the  profile  of  this  case,  Fig.  472,  exhibits  the  extent 
of  the  deformity,  the  chin  being  considerably  protruded,  giving  the 
individual  a  senile  appearance. 

The  model  of  the  mouth  of  this  young  lady  in  Fig.  695  exhibits 
just  such  a  lack  of  harmony  in  occlusion  as  one  would  expect  from  a 
study  of  the  facial  inharmony. 


Fig.  471. 


Fig.  472. 


The  functions  of  speech  and  mastication  are  seriously  impaired, 
and  were  it  not  for  the  skill  of  the  orthodontist,  there  would  be  no 
alleviation  of  the  deformed  condition  which  is  such  a  handicap  to  the 
one  having  such  a  facial  disfigurement. 

PART  III. 


ETIOLOGY. 

Deductions  From  Early  Symptoms  of  Developing  Malocclu- 
sion.— The  establishment  of  diagnostic  interpretations  from  the  basis 
of  occlusion  has  caused  an  earnest  study  of  early  symptoms  of  develop- 
ing malocclusion,  a  very  large  percentage  of  cases  exhibiting  such  pecu- 
liarities of  maldevelopment  of  the  arches  as  a  whole,  as  to  claim  a 
most  serious  consideration  of  the  possible  etiological  characteristics, 
40 


626  ORTHODONTIA. 

and  their  probable  bearing  upon  operative  treatment  of   abnormal 
conditions  present. 

The  exclusion  of  many  local  etiological  factors  in  the  production  of 
small  and  crowded  arches  of  teeth  has  led  to  the  conclusion  that 
malpositions  of  the  teeth,  individually  and  collectively,  are  but  super-- 
ficial  symptoms  of  deficient  or  arrested  function  and  development  of  the 
arches  as  a  whole,  including  the  alveolar  process  and  underlying  bone, 
and  even  extending  into  the  associated  nasal  structures  and  sinuses. 

The  concomitant  arrest  of  development  of  the  nasal  cavities,  and  a 
diagnosis  of  similar  local  or  remote  etiological  factors,  furnishes  the 
strongest  proof  of  the  wisdom  of  observing  and  preventing  abnor- 
malities in  development  during  the  earliest  period  of  child  life,  when 
functional  insufficiency  interferes  most  profoundly  with  the  normal 
growth  of  developing  anatomical  structures. 

Very  marked  malocclusions  of  the  deciduous  teeth,  such  as  pro- 
nounced protrusions,  have  been  not  infrequently  observed  by  the 
author  and  others  in  children  of  two  years  of  age  and  younger,  exhibit- 
ing some  form  of  functional  derangement,  especially  in  the  nose  and 
throat,  and  indicating  defects  in  development  which  may  be  of  congen- 
ital origin. 

These  disturbances  in  development  occur  very  early  in  life,  and  if 
remedial  treatment  is  not  instituted  before  the  sixth  or  seventh  year, 
or  even  earlier  in  some  cases,  the  possibility  of  permanent  benefit, 
especially  in  the  establishment  of  normal  nasal  respiration,  where  it 
is  perverted,  is  greatly  lessened. 

Intra-uterine  Influences  upon  Arch  Development. — The 
normal  development  of  the  dental  arch,  including  the  alveolar  proc- 
ess and  the  deciduous  and  permanent  teeth,  preconceives  primarily, 
the  healthy  structure  and  the  molding  and  development  of  the  maxilla 
and  mandible  during  embryonic  life,  which  are  naturally  dependent 
upon  the  nutritive  and  other  conditions  present  in  intra-uterine  life. 

It  is  conceded  that  prenatal  influences,  whether  they  be  of  a  nutri- 
tional, functional  or  nervous  type,  have  a  definite  bearing  upon  the 
metabolic  processes  which  tend  toward  symmetry  or  asymmetry  of 
development  of  the  embryo  in  whole  or  part. 

Hare-lip  and  cleft  palate  are  recognized  as  simply  lack  of  com- 
plete development  in  the  embryo  through  some  retardation  in  intra- 
uterine development,  the  causes  for  which  are  obscure  only  because  of 
the  inability  to  directly  trace  the  particular  influences  which  might 
arise  from  a  neurotic  or  other  tendency,  which  in  turn  affects  the 


ETIOLOGY.  627 

growth  and  development  of  cellular  structures  in  those  parts  of  the 
human  organism  peculiarly  open  to  such  influences. 

Talbot  remarks:  "The  structures  of  the  mouth  and  nose  being 
exceedingly  variable  in  evolution,  and  the  structures  of  the  jaws  and 
teeth  having  taken  an  embryonic  trend  for  the  benefit  of  the  body  as 
a  whole,  under  the  law  of  economy  of  growth,  disturbances  of  balance 
are  peculiarly  apt  to  occur  here."  "Not  only  is  actual  growth  upset 
by  the  operation  of  this  disturbance  of  balance,  but  certain  poten- 
tialities are  likewise  interfered  with." 

Whatever  the  particular  stress  may  be  which  lowers  potentiality 
or  retards  development  in  the  embryo,  it  is  enough  to  know  that  such 
influences  exist,  and  invariably  affect  the  development  of  particular 
parts  of  the  organism  in  greater  or  lesser  degree. 

Hellman*  remarks,  "If  we  should  examine  the  countless  modifica- 
tions that  a  developing  organism  passes  through  from  inception  to 
parturition,  and  realize  the  underlying  conditions  bringing  about  these 
remarkable  transformations,  until  the  completion  of  an  individual,  we 
shall  not  wonder  that  a  malformation  may  appear  now  and  then,  but 
we  shall  be  surprised  that  such  disturbances  are  not  the  rule  instead 
of  the  exception." 

This  writer  calls  special  attention  to  Ballantyne'sf  charting  of  the 
periods  of  ante-  and  post-natal  development  with  reference  to  the  par- 
ticular form  of  interference  with  developmental  conditions  which  may 
ensue  during  each  period. 

Post-natal  Factors  in  Arch  Development.— After  birth  the  nor- 
mal development  of  the  dental  arch  is  largely  a  question  of  proper 
nutrition  and  function,  recognizing  also,  the  possibility  of  an  insuffi- 
ciency of  nutrition  and  perversion  of  function  with  which  the  child  may 
be  born  into  the  world,  and  from  which  inadequate  foundation,  normal 
function  and  normal  structure  are  not  readily  developed. 

Heredity  and  Environment. — Just  at  this  point  it  may  be  necessary 
to  distinguish  between  the  influences  of  heredity  and  environment,  in 
order  that  a  clearer  conception  of  the  two  may  be  engendered. 

Quoting  from  Brady: J  "The  tendency  to  resemble  ancestry  is  called 
heredity,  and  a  character  or  condition  that  appears  prominently  through 
a  series  of  generations  is  said  to  be  hereditary  or  inherited.  The 
surroundings  of  an  organism  are  called  its  environment,  and  include 

*  Hellman,  Some  Etiological  Factors  of  Malocclusion,  Dental  Cosmos,  Sept., 
1912,  p.  02. 

t  Ballantyne,  Manual  of  Antenatal  Pathology  and  Hygiene. 
X  The  Influence  of  Heredity  on  Malocclusion. 


628  ORTHODONTIA. 

every  possible  condition  which  might  have  any  effect  upon  its  devel- 
opment, such  as  food,  climate,  light,  air,  moisture,  heat,  cold,  cultiva- 
tion, artificial  benefits,  natural  enemies,  companionship,  mental  con- 
dition, method  of  living,  exercise,  in  fact,  any  and  all  things  capable 
of  exerting  any  influence  for  better  or  worse." 

"  Heredity  is  the  force  that  holds  all  life  to  its  true  forms  throughout 
the  ages,  and  its  power  is  not  set  aside  in  a  few  years  even  under  an 
intensely  changeable  environment." 

"Heredity  always  tends  to  promote  the  normal,  the  healthful,  not 
the  abnormal  or  diseased." 

"Aside  from  the  fact  that  heredity  promotes  the  normal  instead 
of  the  abnormal,  it  is  also  very  questionable  if  a  feature  like  mal- 
occlusion can  be  transmitted  at  all.  A  violent  change  is  much  less 
likely  to  be  transmitted  than  a  slight  one,  and  a  bad  case  of  mal- 
occlusion is  certainly  a  great  change  from  the  normal.  Weismann,  the 
great  writer  on  heredity,  gives  it  as  his  opinion  after  years  of  observa- 
tion that  only  slight  acquired  conditions  are  ever  transmitted,  and 
scientists  are  very  cautious  as  to  their  statements  of  what  changes 
may  become  hereditary  and  what  may  not." 

"If  a  similar  condition  exists  in  parent  and  child,  let  us  not  jump 
to  the  conclusion  that  the  defect  is  inherited,  but  rather  let  us  in- 
vestigate the  environment.  If  we  find  contracted  dental  arches  in 
the  same  family  it  is  a  sign  that  all  members  have  lived  upon  the  same 
kind  of  food,  and  all  have  failed  to  give  normal  exercise  to  the  teeth 
and  jaws.  If  nasal  or  pharyngeal  hypertrophies  exist  from  one  genera- 
tion to  another,  we  will  find  the  environment  is  inherited  rather  than 
the  disease." 

Relations  of  Internal  Secretory  Organs  to  Malocclusion. — 
Recent  investigations  have  shown  that  the  entire  chain  of  internal 
secretory  organs,  or  ductless  glands,  are  intimately  connected  with 
the  growth  of  the  whole  body.  Biedl*  remarks:  "  The  results  of  human 
pathology,  especially  the  comparison  of  the  clinical  with  the  post-mortem 
findings,  have  in  other  directions  supplied  the  most  valuable  evidence 
in  favor  of  the  doctrine  of  internal  secretion.  Instances  are  afforded 
by  myxedema  on  the  one  hand,  and  by  exophthalmic  goiter  and  acro- 
megaly on  the  other.  These  pathological  conditions  have  supplied 
facts  concerning  the  physiology  of  the  thyroid  and  pituitary  glands, 
the  value  of  which  is  incalculable." 

Acromegaly,  which  is  a  chronic  disease  characterized  by  overgrowth 
or  enlargement  of  the  bones  and  soft  parts  of  the  hands,  feet,  and  face 
*  Biedl,  Internal  Secretory  Organs. 


ETIOLOGY.  629 

furnishes  a  clinical  picture  of  the  results  of  hypertrophy  of  the  pituitary 
body,  or  with  disease  of  the  thyroid.  Cretinism,  associated  with  thyroid 
disease,  on  the  contrary,  exhibits  the  inhibitory  action  on  body  growth 
as  shown  in  dwarfing  of  the  stature,  idiocy,  and  mental  dullness. 

Gushing*  suggests  that  "There  are  few  subjects  in  medicine  which 
promise  a  wider  overlap  upon  the  field  of  special  workers  than  hypophy- 
seal pituitary)  disease." 

Thus  it  is  that  "  in  view  of  a  new  pathology  based  upon  a  new 
physiology,  which  recognizes  the  internal  secretory  organs,"  as  Grieves 
expresses  it,  the  etiology  of  such  maldevelopmental  conditions  as 
malocclusion  and  facial  deformity  should  include  the  possible  effects 
of  disease  or  insufiQciency  of  these  ductless  glands. 

In  a  summary  of  the  investigations  and  clinical  studies  of  the  internal 
secretory  organs,  Grievesf  has  pointed  out  the  rational  theory  of  such 
an  etiology  of  malocclusion  and  facial  deformity,  through  the  cor- 
relation between  the  physiological  and  pathological  functions  of  these 
glands.  He  says,  "that  all  of  these  tissues  (the  central  and  sympathetic 
nervous  systems)  and  glands  (the  internal  secretory)  compensate  and 
inhibit  each  other  in  cycle,  any  interfering  influence  or  disease  which 
disturbs  this  co-ordination  seriously  and  very  diversely  affects  nutri- 
tion, bodily  development  and  function  according  to  the  time  at  which 
it  occurs,  before  or  after  puberty,  with  the  most  marked  effects  at  the 
periods  of  bodily  stress  and  change,  i.e.,  from  birth  to  tooth  eruption, 
the  first  and  second  dentitions,  puberty  and  menstruation;  pregnancy 
and  lactation  in  the  female,  climacteric  and  senility  in  both  sexes;  that 
the  internal  secretory  organs  have  each  a  special  function  in  these 
important  periods  besides  that  of  growth,  presiding  over  paTturition,, 
controlling  sex  and  sex  characteristics,  promoting  lactation  and  main- 
taining immunity  to  infectious  diseases  in  the  infant,  and  all  of  this  cycle 
is  peculiarly  susceptible  to  damage  from  the  infectious  diseases  of  child- 
hood, as  scarlet  fever,  measles,  chickenpox,  whooping  cough,  etc." 

Also,  "that  normal  development  of  the  bones  of  the  face  and  the 
base  of  the  skull,  the  proper  growth  and  articulation  of  these  with  the 
base  of  the  skull,  the  growth  of  the  nasal  and  post-nasal  regions  and 
accessory  sinuses,  and  the  eruption  of  the  teeth,  all  depend  upon  the 
correct  functioning  of  these  organs  and  their  correlation  with  the  sym- 
pathetic nervous  system,  insufficiency  or  disease  in  any  one,  will  interfere 
with  the  synchronism  of  the  whole,  causing  various  forms  of  deformity, 

*  Gushing,  The  Pituitary  Body  and  its  Disorders, 

t  Grieves,  The  Relation  of  the  Internal  Secretory  Organs  to  Malocclusion,  Fadal 
Deformity,  and  Dental  Disease,  Dental  Cosmos,  Aug.,  1914. 


630  ORTHODONTIA. 

as  in  the  major  expression,  for  instance,  thyroid  disease  producing 
cretinism  and  myxedema,  and  pituitary  disease  producing  acromegaly 
and  giantism,  all  afifecting  facial  regions,  as  in  minor  expression, 
glandular  insufficiency  producing  the  different  forms  of  malocclusion 
and  defects  in  the  teeth  and  their  eruption." 

Grieves  further  points  out  that  breast  feeding  by  supplying  activators 
or  stimulants  to  action  to  the  ductless  glands  has  its  ratio  of  influence 
in  bodily  growth,  and  bottle  feeding,  in  its  lack  of  supply  of  these  same 
activators,  has  a  corresponding  reverse  influence  in  inhibiting  the 
action  of  these  glands  and  retarding  development,  not  only  of  the  whole 
body,  but  especially  of  the  teeth  and  jaws,  and  facial  bones. 

Thyroid  insufficiency  and  hypopituitarism  represent  enough  of  the 
derangement  of  function  of  two  of  these  glands  and  consequent  malde- 
velopment  of  the  body  so  that  the  less  known  pathology  of  the  thymus, 
the  suprarenals,  the  spleen,  and  other  ductless  glands  may  well  be  con- 
sidered with  a  view  to  throwing  further  light  on  the  etiology  of  such 
peculiar  conditions  of  maldevelopment  as  present  to  the  orthodontist. 

Functional  Influences. — After  birth,  the  influences  which  tend  to 
normal  arch  development  are  largely  functional,  influenced  of  course 
by  environment. 

Succeeding  mammary  function,  which  is  believed  to  have  consider- 
able influence  upon  general  developmental  conditions  in  infancy,  the 
function  of  mastication,  and  the  proper  use  of  the  muscles  of  the  tongue, 
cheeks  and  lips,  are  the  most  important  factors  in  the  development  of 
the  dental  arch  after  dentition  is  complete.  The  exclusion  of  other 
factors  which  would  tend  to  retard  development,  such  as  anemia  in- 
fluenced by  malnutrition,  and  other  constitutional  conditions,  and  the 
absence  of  nasal  or  post-nasal  obstruction  to  normal  breathing,  are 
essential  to  the  normal  growth  of  maxillary  structures  and  the  proper 
sequence  of  functions. 

Normal  Muscular  Action. — As  illustrative  of  the  effect  of  normal 
muscular  action  upon  the  development  of  bone  in  the  maxilla  and 
mandible,  the  lines  of  stress  in  developing  bone  caused  by  muscular 
action  as  seen  with  the  X-ray  by  Walkhoff,  offer  sufficient  evidence 
of  the  influence  of  muscular  action  in  development,  not  only  in  embryo 
and  infancy,  but  also  during  the  entire  period  of  development  of  the 
dental  arches  up  to  the  time  of  the  eruption  of  the  last  permanent 
tooth. 

This  investigator  has  demonstrated  conclusively  that  the  stress 
upon  the  surface  of  the  bone  through  the  muscular  attachments  was 
directly  related  to  the  internal  development  of  and  arrangement  of 


ETIOLOGY. 


631 


the  bone  spicules,  which  form  themselves  in  lines  parallel  to  the  direc- 
tion of  the  exertion  of  the  muscular  force  upon  the  external  surface  of 
the  bone. 

Disuse  0}  the  muscles  0}  mastication,  or  their  abnormal  use, 
therefore,  must  have  its  efifect  in  the  deficiency  and  abnormality  of 
development  in  the  dental  arches. 

The  disappearance  of  the  angle  formed  by  the  rami  and  body  of 
the  mandible  in  certain  pronounced  mouth-breathers  of  Class  III  is 
an  evidence  of  the  influence  of  abnormal  muscular  action  uppn  the 
shape  of  the  underlying  bone. 

Inflammatory  Changes  in  Alveolar  Tissues.— The  thickening 
and  hardening  of  the  cancellated  and  cortical  portions  of  the  alveolar 
process  through  suppurative  conditions  caused  by  diseased  teeth  in- 
terferes with  normal  and  uniform  development  of  the  bony  tissues  in 
which  these  changes  take  place,  and  no  doubt  is  causative  of  some  of 
the  peculiarities  of  development  of  the  dental  arches,  especially  of 
tooth  impaction. 


Tooth-sacs  of 
Permanent  Teeth 


^''^^^ 

■^_  ^_^a: 

^^^ 

M 

%^^£* 

is.  / 

■    ^ 

wt^"^^  f  '^*Vr 

^; 

wnf^^sm^ 

1      .  . 

Tooth-sacs  of 
Deciduoiis  Teeth 


Periosteum  of  Hard  Palate 

Fig.  473. — Tooth-follicles  for  deciduous  and  permanent  teeth, 
three  months  after  birth.     (Broomell.) 


Disease. — The  influence  of  such  diseases  as  rickets,  syphilis,  and 
others  may  seriously  affect  the  development  of  the  osseous  structures  of 
the  maxillae.  Malocclusion  is  often  a  result  of  pyorrhea,  the  teeth 
becoming  elongated,  and  forced  into  malpositions  through  the  undue 
influence  of  their  own  inclined  planes. 

Abnormal  Arch  Development. — In  consideration  of  the  factors 
in  dental  arch  development  which  have  been  stated,  it  is  interesting 
to  note  the  positions  of  the  permanent  tooth  follicles  at  a  period  in 
child  life  when  the  deciduous  teeth  are  unerupted,  and  speculate  upon 


632 


ORTHODONTIA. 


the  possibilities  of  arrested  development  upon  the  permanent  arches  of 
teeth. 


Fig.  474. 


Fig.  475- 


Fig.  473  represents  the  dissected  tooth  follicles  of  the  deciduous  and 
permanent  teeth  in  the  mouth  of  a  child  three  months  after  birth,  the 


ETIOLOGY. 


633 


plastic  tissues  in  the  center  of  the  cut  being  the  periosteum  covering 
the  hard  palate,  the  tooth  follicles  being  imbedded  and  firmly  adherent 
to  the  fibrous  tissues  laterally  and  anteriorly. 

The  tooth  sacs  of  the  deciduous  teeth  are  upon  the  periphery, 
being  external  to,  and  larger  than  the  sacs  of  the  permanent  teeth. 
The  arch  of  the  deciduous  teeth,  which  are  nearly  ready  for  eruption 
anteriorly,  is  very  nearly  uniform  in  shape  and  development,  while  that 
of  the  permanent  teeth  has  not  at  this  age  even  assumed  any  definite- 
ness  in  the  uniformity  or  position  of  its  teeth,  the  four  permanent  in- 
cisors being  more  fully  developed  than  the  cuspids  and  bicuspids, 
but  the  lingual   position  of  the  laterals  indicates  that  considerable 


Fig.  476. 


Fig.  477. 


arch  development  must  take  place  before  there  will  be  sufficient  space 
for  these  teeth  to  erupt  into  their  normal  positions  in  line  with  the 
centrals. 

If,  by  reason  of  any  infantile  cachexia,  such  as  malnutrition,  from 
whatever  cause,  arrest  of  arch  development  should  occur  at  this  age,  or 
even  later  up  to  five  or  six  years  of  age,  the  resultant  effect  upon  the 
arch  of  the  permanent  teeth  might  be  such  as  is  illustrated  in  the  two 
casts  shown  in  Figs.  474  and  475  at  the  ages  of  seven  and  twenty-seven, 
in  which  the  positions  of  the  central  and  lateral  incisors  are  seen  to  be 
almost    identical  with  those   of   the   permanent    incisor  follicles  in 

Fig.  473- 

It  will  be  observed  that  the  adult  arch  in  Fig.  475  did  not  develop 


634 


ORTHODONTIA. 


any  larger  than  the  arch  of  the  deciduous  teeth  in  Fig.  474,  the 
arrest  of  development  being  almost  permanent  except  for  the  eruption 
of   the  permanent  teeth  into  positions  of  irregularity,  so  great  was 


Fig.  478. 


the  functional  disturbance  which  left  its  impress  upon  the  maxilla 
and  overlying  processes. 

Another  interesting  feature  about  the  case  of  this  adult  is  that 
there  was  no  apparent  facial  deformity  except  the  slightly  marked 
deviation  of  the  central  facial  line  at  the  age  of  four,  see  Fig.  476, 


ETIOLOGY,  635 

but  at  the  age  of  twenty-seven,  Fig.  477,  the  distortion  of  the  facial 
lines  indicates  serious  malocclusion  and  maldevelopment. 

Again,  in  Fig.  478,  is  observed  the  upper  deciduous  arch  of  a  four 
year  old  child,  and  the  undeveloped  upper  arch  of  a  ten  year  old 
child.*  The  feature  of  striking  interest  in  the  case  is  the  fact  that  the 
arch  of  the  ten  year  old  child  is  scarcely  larger  and  is  not  more  developed 
than  that  of  the  child  of  four  with  which  it  is  compared. 

Such  studies  as  these  prove  to  the  observer  that,  although  the  func- 


FiG.  479. 

tion  of  occlusion  is  perverted,  and  its  beneficial  influence  upon  the 
growth  of  the  dental  arches  lacking,  there  are  still  present  causative 
factors  of  the  arrested  development,  of  either  prenatal  or  post-natal 
origin,  which  must  be  given  due  consideration. 

^Mouth-breathing. — One  of  the  most  serious  abnormal  conditions 
with  which  the  rhinologist  and  the  orthodontist  have  to  deal,  and  one 
as  intimately  connected  with  the  disturbance  of  normal  function  and 
structure  in  the  field  of  the  one  as  in  that  of  the  other,  is  the  partial  or 
complete  loss  of  normal  respiratory  function  through  the  obstruction 
of  the  nasal,  naso-pharyngeal,  and  oro-pharyngeal  air  passages,  causing 
oral  respiration,  commonly  known  as  mouth-breathing. 

That  this  condition,  with  all  of  its  injurious  results  upon  the  de- 


636  ORTHODONTIA. 

velopment  of  the  bones  of  the  head  and  face,  the  disfiguring  of  the 
features,  and  the  undermining  of  the  general  heaUh,  is  becoming  more 
prevalent,  one  hardly  needs  statistics  to  show,  in  view  of  the  great 
numbers  of  those  afflicted  with  this  trouble  in  all  walks  of  life. 

Fig.  479  represents  the  face  mask  of  a  typical  mouth-breather, 
the  characteristic  features  noticeable  being  the  open  and  drooping 
mouth,  the  short  upper  lip,  the  undeveloped  nose  and  undilated  nos- 
tril, and  the  malocclusion  of  the  teeth. 

The  vacant  stare  especially  accompanies  the  presence  of  large  ade- 
noids, and  is  said  to  be  caused  chiefly  by  the  stagnation  of  lymph 
at  the  base  of  the  skull. 

On  examination  of  the  relations  of  the  arches  of  teeth  (Fig.  480) 


Fig.  480.  Fig.  481. 

of  the  patient  whose  face  mask  is  illustrated  in  the  previous  figure, 
it  will  be  noticed  that  arrested  and  abnormal  development  of 
the  arches  of  teeth  is  in  evidence,  sufficient  to  cause  a  very  great  lack 
of|harmony  of  the  facial  lines.  The  upper  arch  is  narrow  and  elon- 
gated, the  upper  bicuspids  and  molars  being  in  lingual  occlusion,, 
and  the  lower  arch  distal  to  its  normal  position,  a  case  of  the  first 
division  of  Class  II,  Angle's  classification. 

It  has  been  the  observation  of  the  author  that  a  mouth-breather  may 
present  a  malocclusion  of  any  one  of  the  different  classes  into  which  it 
is  possible  to  divide  the  abnormal  relations  of  occlusion,  rather  than  of 
only  one  or  two  of  them,  as  has  been  suggested  by  some  writers.  The 
shapes  of  the  arches  of  teeth  are  varied,  also,  and  the  extent  of  the  mal- 
occlusion measured  somewhat  by  the  degree  to  which  oral  respiration 
is  resorted  to. 

One  of  the  most  aggravating  forms  of  malocclusion  associated  witb 


ETIOLOGY. 


637 


mouth-breathing  is  that  of  the  "open-bite"  malocclusion,  as  it  has 
been  termed  by  some  writers.  Lack  of  anterior  occlusion  and  "infra- 
occlusion"    are   similar   designations   for   the   same   condition.     Fig. 

481  illustrates  such  a  case 
belonging  to  Class  I. 
There  is  a  noticeable  lack 
of  development  of  both 
arches  in  this  case,  there 
being  insufficient  growth 
for  the  eruption  of  the  per- 
manent teeth,  especially 
in  the  incisor  region.      Fig. 

482  exhibits  a  very  com- 
mon form  of  malocclusion, 
of  Class  II,  Div.  i,  found 
among  mouth-breathers, 
the  lower  arch  being  distal  to  normal  in  occlusion,  and  the  shortness 
of  the  upper  lip,  and  therefore  lack  of  function  in  supporting  the 
incisors,  allowing  them  to  protrude  to  a  considerable  extent,  a  con- 
dition which  is  intensified  by  the  lower  lip  adjusting  itself  between 
the   upper   and   lower  incisors    and    forcing   the  upper  incisors   still 


Fig.  482. 


Fig.  4S3. 


Fig.  484. 


farther, forward,  and  further  aggravated  by  the  wrong  tension  of  the 
muscles  of  the  upper  lip  over  the  canine  region. 

The  elongation  of  the  upper  incisors  from  non-support  of  the  lower 
incisors  follows,  and  the  articular  motions  of  the  mandible  still  farther 
extends  the  protrusion  of  the  upper  incisors.  A  very  similar  in- 
harmony  of  occlusion  of  the  anterior  teeth  and  disfigurement  of  facial 
lines  is  often  seen  in  the  protrusion"^  of  Class  I. 


638  ORTHODONTIA. 

It  is  believed  that  the  distal  position  of  the  lower  arch  in  cases  of  this 
class  is  caused  primarily  by  the  lack  of  lateral  development  of  the  upper 
arch,  because  expansion  of  the  upper  arch  in  the  early  treatment  of 
these  cases  often  restores  the  normal  relations  of  occlusion  in  the 
molar  region,  by  allowing  a  farther  forward  position  of  the  mandible 
without  cusp  interference. 

Figs.  483  and  484  represent  a  mouth-breather  at  the  ages  of  six 
months  and  seven  years  respectively,  and  it  will  be  noted  that  the  open 
and  drooping  mouth  and  other  symptoms  are  plainly  noticeable  in  both 
pictures,  showing  that  the  mouth-breathing  was  of  early  origin,  and 
had  persisted  and  become  more  aggravated  in  its  symptoms  as  the 
child  grew  older. 

The  casts  of  the  child's  teeth  in  occlusion  in  Fig.  485  exhibit  a  maloc- 
clusion of  Class  II,  Div.  i  (Angle).     Both  arches  are  contracted  and  un- 


FiG.  485 

developed,  there  being  insufficient  space  for  the  eruption  of  the  upper 
and  lower  lateral  incisors,  and  in  addition,  the  lack  of  anterior  occlusion. 

Mouth-breathing  is  usually  regarded  as  a  habit,  but  in  reality  is  a 
necessity,  because  of  the  inability  to  breathe  properly  through  the  nose, 
there  being  a  lack  of  development  of  full  nasal  space,  or  inflammatory 
conditions,  or  some  impediment  in  the  nasal  tract  which  will  not  allow 
sufficient  air  to  pass  through. 

Obstructions  to  Nasal  Breathing. — Among  the  various  obstruc- 
tions to  nasal  breathing  may  be  mentioned  deflection  of  the  nasal 
septum,  hypertrophied  tonsils  and  turbinate  bones,  adenoids,  and  the 
diseased  conditions  resulting  from  syphilis,  tumors,  polypi,  and  cysts. 

"If  the  nasal  and  post-nasal  passages  are  unobstructed,  every 
inspiration   empties   the  ethmoid  veins  and  through  them  the  longi- 


ETIOLOGY. 


639 


tudinal  sinus  and  cavernous  plexus.  When  there  is  obstruction  to 
nasal  respiration,  the  circulation  at  the  base  of  the  skull  is  interfered 
with,  and  a  long  train  of  ills  brought  about  which  interferes  very  greatly 
with  the  health  of  the  individual.  In  the  first  place,  the  quantity  of  air 
aspirated  through  the  mouth  in  a  case  of  nasal  obstruction  is  not 
equal  to  that  of  normal  nasal  respiration,  and  the  system  suffers  from 
lack  of  sufficient  oxygenation"  (Griinwald). 

Ziem's  experiments  in  producing  nasal  stenosis  in  young  animals 
by  occluding  one-half  of  the  nose  artificially,  with  the  result  of  the 
asymmetrical  development  of  the  two  sides  of  the  nose  and  adjacent 
bony  tissues,  the  obstructed  half  being  arrested  in  development,  as 
well  as  the  contiguous  tissues  on  that  side  of  the  face,  are  worthy  of 


Fig.  486. 


note  as  proof  of  the  correctness  of  the  theory  that  nasal  obstruction 
is  causative  of  arrest  of  development  in  the  human  head  and  face. 

It  is  important  that  the  diagnosis  of  the  obstruction  of  the  air 
passages  should  be  made  as  early  as  possible  after  its  incipiency,  so 
that  by  proper  treatment  and  operation,  if  necessary,  normal  develop- 
ment may  not  be  more  seriously  interfered  with,  and  the  health  of 
the  child  seriously  impaired.  There  are  so  many  local  symptoms  of 
this  abnormal  condition  that  even  the  novice  ought  to  be  able  to 
diagnose  it. 

Vocalization  is  impaired,  especially  in   the   pronunciation   of  the 


640 


ORTHODONTIA. 


letters  m  and  n,  which,  in  the  muffled  voice  of  the  mouth-breather 
sound  like  b. 

A  persistent  catarrhal  condition,  often  mistaken  by  parents  for 
an  ordinary  cold,  together  with  an  unusual  dryness  of  the  pharyngeal 
mucous  membrane,  and  the  continued  drooping  open  of  the  mouth, 
ought  to  give  warning  of  the  beginning  of  serious  nasal  obstruction. 

If  allowed  to  continue,  deficient  nasai  respiration  may  be  causa- 
tive of  arrested  development,  not  only  in  the  face  and  head,  but  in  other 
parts  of  the  body,  insufficient  oxygenation  causing  anemic  conditions 
of  the  general  system,  the  dulling  of  the  mental  faculties,  and  a  favor- 
able opportunity  for  the  inception  of  infectious  diseases,  especially 
tuberculosis. 

Deviation  of  Nasal  Septum. — In  the  normal  subject  the  nasal 
septum  occupies  a  position  in  the  nasal  cavity  dividing  one-half  of  the 
nose  from  the  other. 

Slight  deviations  are  frequently  seen  in  people  who  are  not  troubled 
with  nasal  stenosis  to  any  degree,  but  where  there  is  an  extensive  devia- 
tion from  the  median  line,  oc- 
clusion of  the  side  toward  which 
the  deviation  takes  place  occurs, 
with  consequent  deficient  nasal 
and  enforced  mouth-breathing. 
Fig.  457  illustrates  a  skull  sec- 
tion (from  Cryer)  in  which  the 
nasal  septum  is  in  its  normal 
median  position,  the  choanae  on 
each  side  being  equal  in  size. 

Fig.  486  portrays  a  marked 
deviation  of  the  septum  to  the 
right.  The  choana  on  the  side 
toward  which  the  septum  is  de- 
flected is  very  much  smaller  than 
the  other,  and  must  have  been 
almost  completely  occluded  dur- 
ing life,  and  there  is  every  reason  to  believe  that  the  subject  was  a 
mouth-breather. 

Operations  for  the  straightening  or  partial  removal  of  the  septum 
when  deflected,  are  of  common  occurrence,  and  are  usually  followed 
by  immediate  relief  in  cases  of  deficient  nasal  respiration. 

Hypertrophy  of  Faucial  Tonsil. — Another  cause  of  nasal 
stenosis   is   the    hypertrophy   of    the    faucial    tonsils,   and   from  the 


Fig.  487. 


ETIOLOGY. 


641 


frequency  with  which  operations  for  their  removal  are  performed,  their 
diseased  condition  and  obstruction  to  nasal  breathing  cannot  be 
judged  uncommon. 

The  faucial  tonsils  are  frequently  the  seat  of  infection  and  disease 
because  of  a  hypertrophied  condition  and  improper  per- 
formance of  function. 

The  large  globular  masses  of  tissue  in  Fig.  487  are 
the  faucial  tonsils  removed  from  the  throat  of  a  two 
year  old  child,  and  are  so  hypertrophied  that  they 
nearly  occluded  the  throat. 

Hypertrophy  of  the  turbinate  bones,  especially  the  inferior, 
is  not  an  infrequent  cause  of  nasal  stenosis,  and  consequent  mouth- 
breathing.  Fig.  488  exhibits  a  portion  of  the  inferior  turbinate  which 
was  removed  from  the  nose  of  a  patient  who  was  suffering  from 
partial  nasal  stenosis. 

Adenoids. — One  of  the  most  common  causes  of  mouth-breathing  is 
found  in  the  hypertrophy  of  the  pharyngeal,  or  Luschka's  tonsil,  which 


Fig.  488. 


Fig.  489. 


is  situated  in  the  vault  of  the  naso-pharynx,  usually  just  out  of  sight 
above  the  uvula. 

A  mass  of  this  enlarged  glandular  tissue  may  be  seen  in  Fig.  489, 
being  a  posterior  rhinoscopic  view  of  the  naso-pharynx,  and  it  can 
be  readily  understood  that  the  naso-pharyngeal  passages  may  become 
partially  occluded  by  the  downward  growth  of  this  tissue. 

Parke  Lewis  has  called  attention  to  the  possibility  of  impairment 
of  function  of  nutritive  vessels  passing  through  the  carotid  canal 
41 


642  ORTHODONTIA. 

(which  bears  the  carotid  artery,  the  superior  cervical  sympathetic 
and  the  lymphatics)  through  the  pressure  of  adventitious  growths  in 
the  naso-pharynx  upon  the  tissues  which  pass  through  the  foramen 
lacerum  medium,  which  is  immediately  above  the  site  occupied  by 
the  adenoid  tissues,  and  which  opens  into  the  carotid  canal. 

The  conclusions  of  Parke  Lewis  are  based  upon  those  of  Sajous  in 
regard  to  the  control  of  all  oxygenation  processes  in  the  body  through 
the  pituitary  bodies,  which  are  very  closely  associated  with  the  nutrient 
vessels  passing  through  the  carotid  canal. 

Sajous'  Theory.  —Sajous  indicates  the  significance  of  these  organs 
and  their  physiological  and  pathological  importance  in  this  connection 
as  follows:  "It  will  be  apparent  that  any  lesion  capable  of  blocking 
the  afferent   and   efferent   impulses  that  traverse  it  at  all  times,  and 


Fig.  490. 

which  represent  the  aggregate  of  the  organism,  inciting  and  governing 
energy,  must  necessarily  compromise  life,  or  the  functions  of  an  organ 
to  which  the  blocked  nerves  are  distributed." 

"The  large  mortality  under  chloroform  in  adenectomy  is  in  all 
probability  due  to  the  shock  conveyed  to  the  posterior  pituitary  body 
through  the  foramen  lacerum  medium  immediately  over  the  lymphatic 
enlargements." 

"It  will  readily  be  seen,  therefore,  that  whatever  interferes  with 
the  nutritive  functions  at  the  vault  of  the  pharynx  may  disturb  the 
subsequent  development  of  the  whole  skull  and  its  contents." 


ETIOLOGY.  643 

The  very  close  relationship  which  exists  between  the  tissues  of  the 
pharynx,  and  the  nutritive  vessels  of  the  carotid  canal  may  be  seen 
from  observation  of  the  position  and  direction  of  the  more  nearly 
vertical  of  the  two  probes  passing  through  the  skull  section  in  Fig.  488, 
it  being  passed  through  the  foramen  lacerum  medium  and  emerging 
into  the  space  occupied  by  the  pituitary  body.  The  inferior  opening 
of  the  foramen  lacerum  medium  is  in  the  adenoid  region,  and  the 
vessels  which  enter  it  are  very  apt  to  be  impinged  upon  by  hyper- 
trophy of  the  pharyngeal  tonsils,  and  the  nutrient  and  nerve  supply 
to  the  pituitary  bodies  cut  ofif  enough  to  materially  aflfect  the  proper 
performance  of  the  functions  of  these  organs,  with  consequent  disturb- 
ance of  development  of  the  whole  skull  and  its  contents,  as  well  as 
that  of  the  entire  organism. 

The  horizontal  probe  in  Fig.  490  passes  through  the  optic  foramen 
into  the  space  occupied  by  the  pituitary  bodies,  illustrating  the  very 
close  relationship  between  the  vessels  of  the  eye  and  the  pituitaries, 
and  suggesting  the  probability  of  visual  defects  and  insufficiencies 
from  hypertrophied  tissues  in  the  naso-pharynx. 

Talbot,*  in  his  work,  also  notes  the  possible  influence  of  the  pituitary 
body  on  the  growth  of  the  palate  and  of  bone.  He  says,  "In  dealing 
with  the  development  of  the  palate,  both  pre-  and  post-congenitally, 
the  relations  of  the  hypophysis,  or  pituitary  body,  have  to  be  taken 
into  account,  since  it  has  been  well  demonstrated  that  this  body  exerts 
an  influence  over  body  growth  and  the  structures  thereto  related." 
.  .  .  .  "  Strain  on  the  development  of  the  hypophysis  after  birth  can 
not  only  produce  undue  growth  of  bone,  but  can  also  check  development 
of  it."* 

Removal  of  Adventitious  Growths. — Granting  that  the  theory 
of  pressure  from  the  impingement  of  adventitious  growths  in  the  pharynx 
upon  the  nutrient  vessels  and  nerve  supply  of  the  pituitaries  has  not 
been  really  demonstrated,  it  would  hardly  seem  to  be  necessary  to  argue 
the  necessity  of  early  treatment  of  malocclusion  and  the  removal  of 
all  nasal  and  post-nasal  obstructions  to  nasal  lespiration,  thus  promot- 
ing normal  developmental  conditions  before  the  period  of  normal  and 
rapid  growth  has  passed,  and  choosing  the  opportunity  of  greatest 
benefit  to  the  patient. 

Irreparable  damage  may  be  done  by  the  neglect  to  observe  the  early 
symptoms  of  nasal  obstruction,  and  by  the  failure  to  place  the  patient 
in  the  hands  of  a  competent  rhinologist  for  operative  treatment. 

*  Talbot,  Etiology  of  Cleft  Falate,  Sec.  V,  Page  195;  Trans.  Fourth  Internat.  Dental 
Congress. 


644 


ORTHODONTIA. 


The  operation  for  the  removal  of  post-nasal  obstructions  is  a  com- 
paratively slight  one,  some  cases  not  even  requiring  the  use  of  a 
general  anesthetic,  although,  where  the  faucial  tonsils  as  well  as  the 
adenoids  are  to  be  removed^  the  more  thorough  surgery  in  this  region 
is  assured  under  general  anesthesia. 

Fig.  491  represents  a  very  characteristic  expression  of  a  mouth- 
breather  of  four  years  of  age,  who  later,  at  the  age  of  seven,  was 
brought  to  the  author  for  treatment  of  malocclusion. 

The  segregated  mass  of  tonsillar  adenoid  tissue  shown  in  Fig.  492 
was  removed  from  the  naso-pharynx  of  this  patient  by  a  rhinologist, 
before  treatment  of  the  malocclusion  was  instituted. 


Fig.  491. 

A  diagnosis  of  the  malocclusion  revealed  the  mesial  occlusion  of 
the  lower  arch  of  teeth  as  seen  in  Fig.  691,  and  the  restoration  of  the 
normal  mesio-distal  relations  of  the  arches  resulted  in  the  change  of 
occlusion  noted  in  Fig.  692,  the  operation  being  performed  entirely 
upon  the  deciduous  teeth.  The  change  in  the  appearance  of  the 
boy's  face  from  the  mouth-breather  in  Fig.  493,  with  his  features  all 
distorted  in  his  efforts  to  close  the  mouth,  to  the  calm,  peaceful  facial 
lines  after  the  removal  of  these  obstructing  growths  and  correction  of 
the  malocclusion,  in  Fig.  494,  indicates  the  advantage  gained  by  early 
operating  in  this  class  of  cases. 


ETIOLOGY. 


645 


The  development  of  this  face  along  normal  lines  of  growth    is 
now  assured  and  there  is  nothing  left  undone  to  insure  the  very  best 


Fig.  4g2. 

results  in  the  restoration  of  facial  harmony  and  normal  respiration, 
and  consequently  the  attainment  of  proper  physical .  development 
which  in  this  case,  was  alreadv  deficient. 


Fig.  493. 


Fig.  494. 


Mechanical  assistance  in  holding  the  mouth  closed  after  removal 
of  nasal  obstructions,  and  correction  of  malocclusion,   such  as  the 


646  ORTHODONTIA. 

wearing  of  head  bandages  and  mouth  plasters,  is  beneficial  in  the 
treatment. 

Irremediable  harm  is  done  by  the  oft  repeated  advice  to  "wait 
until  the  permanent  teeth  are  all  erupted  before  beginning  operations 
for  correction  of  malocclusion,"  and  even  greater  damage  may  be  done 
by  the  neglect  to  observe  the  early  symptoms  of  nasal  obstruction, 
and  the  immediate  reference  of  the  patient  to  a  competent  rhinologist 
for  operative  treatment. 

Deformed  arches  of  teeth  and  disfigured  features  become  confirmed 
in  their  abnormality  after  a  long  period  of  abnormal  development, 
and  neither  the  local  tissues  nor  the  general  system  will  res[)ond  to 
remedial  measures  to  anything  like  the  degree  that  they  would  had 
they  been  operated  on  at  an  early  age. 

The  head  contains  the  portals  of  the  human  body,  and  it  should  be 
the  duty  of  the  orthodontist  to  guard  against  any  ill  effects  to  the 
health  through  the  neglect  of  the  oral  cavity,  its  teeth,  and  related 
structures  of  nose  and  throat.  Mouth-breathing,  especially,  should  be 
prevented  by  such  means  as  are  at  one's  command,  with  the  aid  of  the 
rhinologist,  and  the  correction  of  such  resulting  defects  in  occlusion 


Fig  495- 

of  the  teeth  and  inharmony  of  the  facial  lines  as  may  be  necessary  at 
the  time  the  case  presents  with  the  symptoms  of  nasal  stenosis. 

Local  Factors  in  Malocclusion. — Among  the  local  causes  of 
malocclusion  of  the  teeth  may  be  mentioned;  prolonged  retention  of 
deciduous  teeth,  premature  loss  of  deciduous  teeth,  loss  of  permanent 
teeth,  thumb-sucking  and  lip-biting,  supernumeraries,  and  abnormal 
frenum  labium. 

Prolonged  Retention  of  Deciduous  Teeth.— The  retention  of  a 
deciduous  tooth  beyond  the  time  for  its  natural  Iqss  through  absorptioB 


ETIOLOGY.  647 

of  its  roots  forms  a  mechanical  barrier  to  the  normal  eruption  of  its 
permanent  successor,  which  is  deflected  labially,  buccally,  or  lingually. 
The  permanent  central  incisors  in  Fig.  495  were  deflected  lingually 
through  the  prolonged  retention  of  the  deciduous  centrals,  the  roots 
of  which  did  not  absorb. 

As  soon  as  these  conditions  are  observed,  the  deciduous  teeth  which 
have  been  retained  beyond  the  time  for  their  natural  loss  should  be 
extracted,  and  the  permanent  teeth  which  have  been  deflected,  assisted 
into  normal  positions  in  the  arch. 

Premature  Loss  of  Deciduous  Teeth. — One  of  the  prolific 
secondary  causes  of  malocclusion  and  lack  of  arch  development  is 
the  premature  loss  of  the  deciduous  teeth,  especially  of  the  incisors 
and  cuspids.  That  the  mechanical  influence  of  the  deciduous  teeth 
in  assisting  in  the  development  of  the  arch  is  a  necessity  up  to  the  time 
when  natural  absorption  of  the  roots  of  the  deciduous  teeth  should 
take  place,  one  has  only  to  observe  the  contraction  of  the  spaces 
occupied  by  prematurely  lost  deciduous  teeth  to  readily  understand. 


Fig.  496. 

An  illustration  of  the  retarded  development  caused  by  the  pre- 
mature extraction  of  all  deciduous  teeth  at  eight  years  of  age  may  be 
seen  in  Fig.  496.  It  is  easy  to  prognosticate  a  serious  malocclusion  upon 
the  eruption  of  the  remaining  permanent  teeth. 

The  loss  of  the  approximal  surfaces  of  the  deciduous  teeth  by 
caries  is  also  causative  of  lack  of  arch  development  through  the  loss 
of  the  mechanical  influence  of  the  deciduous  teeth  hi  their  entire 
mesio-distal  diameters,  and  such  carious  conditions  should  be  observed 
in  their  earliest  stages  and  fillings  inserted  to  restore  full  approximal 
contour. 

The  loss  of  permanent  teeth  through  extraction  or  disease,  by  de- 
stroying arch  integrity  is  another  frequent  cause  of  malocclusion,  which 
is  considered  under  the  heading,  "The  Problem  of  Extraction." 


648  ORTHODONTIA. 

Thumb-sucking  and  Lip-biting. — The  habits  of  thumb-sucking, 
lip  and  tongue  biting  are  responsible  for  the  inception  of  some  maloc- 
clusions, and  for  the  aggravation  of  a  very  great  many  cases,  with 
other  primary  causative  factors. 

Thumb-sucking  is  not  as  frequent  a  causative  factor  in  malocclusion 
as  is  generally  supposed,  but  that  it  does  affect  the  development  of 
the  arch  is  certain.  Usually,  but  one  side  of  the  mouth  is  aflfected, 
according  to  which  thumb  is  used,  although  it  is  not  uncommon  to 
find  that  the  thumb  is  held  in  the  center  of  the  mouth,  protruding  the 
upper  central  incisors.  When  the  thumb  is  held  on  either  side  of  the 
center,  the  upper  incisors  on  the  side  in  which  the  habit  is  induced 
are  protruded. 

In  Class  I  and  II  cases  in  which  the  upper  incisors  are  protruded, 
the  habit  of  biting  the  lower  lip  has  a  pernicious  influence  in  increasing 
the  extent  of  the  malocclusion,  and  in  some  cases  is  believed  to  be  the 
initial  cause  of  the  abnormal  occlusal  relations. 

The  inculcation  of  a  similar  habit  with  the  tongue  is  productive 
of  more  or  less  deviations  from  the  normal  in  occlusal  relations,  and 
the  observance  of  any  of  these  habits  by  the  parent  or  dentist  should 
be  followed  by  efforts  on  their  part  to  overcome  the  habit  and  the 
damage  already  done. 

Prevention  of  Thumb-sucking. — A  very  practical  method  of 
preventing  a  child  from  sucking  the  thumb  is  to  enclose  its  hands  in 


Fig.  497- 

polished  aluminum  balls,  such  as  is  shown  in  Fig.  497,  an  attachment 
being  made  by  a  sleeve  to  the  child's  arm,  and  worn  as  much  of  the 
time  as  possible,  especially  at  night,  until  the  habit  is  broken  up. 

The  wearing  of  a  simple  apparatus  of  this  kind  will  enable  the  child 
to  use  its  arms,  yet  at  the  same  time,  prevent  the  possibility  of  getting 
the  fingers  or  thumbs  into  the  mouth,  and  is  much  more  humane  than 
tying  the  arms.  The  balls  are  ventilated  by  several  small  holes,  and 
the  sleeve  and  ball  may  be  easily  sterilized  by  boiling. 

Supernimierary  Teeth.— Supernumerary  teeth  are  occasionally 
found  in  the  mouth,  and  are  often  of  the  peg-shaped  variety  shown  in 


DIAGNOSIS.  649 

Fig.  498,  occasionally  presenting  with  several  irregular  cusps,  although 
sometimes  resembling  an  adjacent  normally  developed  tooth  to  such 
an  extent  that  an  X-ray  diagnosis  is  necessary  to  differentiate  between 
them.  Their  removal  is  usually  indicated,  and  the  restoration  to 
normal  position  of  the  teeth  which  have  been  forced  out  of  their 
alignment. 

Abnormal  Frenum  Labium. — The  abnormal  attachment  of  the 
frenum  labium  sometimes  causes  the  separation  of  the  upper  central 
incisors,  acting  as  a  rubber  cushion  to  force  these  two  teeth  apart. 
Cases  of  this  character  are  somewhat  difficult  to  treat,  although 
operative  measures  are  now  seldom  resorted  to  for  the  partial  removal 
of  the  ligament. 


Fig.  49S. 

PART  IV. 

DIAGNOSIS. 

General  Considerations. — A  thorough  diagnosis  of  any  case  of 
malocclusion  should  include  the  observance  of  every  pathological  in- 
dication in  the  oral  cavity  and  adjacent  parts  of  the  head  and  face, 
for  only  with  a  full  understanding  of  the  variations  from  normal  con- 
ditions is  it  possible  to  produce  the  best  results  in  treatment. 

If  the  deciduous  teeth  are  present  in  part  or  whole,  it  should 
be  noted  whether  they  occupy  their  full  mesio-distal  space,  and 
are  assisting  by  their  presence  in  the  development  of  the  arches. 
Their  premature  loss  is  usually  indicated  by  a  closing  up  of  part 
or  all  of  the  space  which  they  originally  occupied,  and  indicates 
non-development. 


650  ORTHODONTIA. 

A  primary  examination  of  the  permanent  denture  should  first  deal 
directly  with  each  individual  arch,  noting  the  absence  of  teeth,  and 
their  effect  upon  each  arch,  tracing  minutely  the  changes  incident  to 
their  removal  in  the  contraction  of  the  arch,  and  secondarily  the 
effect  upon  the  occlusion  and  articulation. 

Accurate  plaster  models  should  be  made  and  the  normal  sizes  of 
the  arches  determined  by  a  method  of  arch  pre-determination  to  be 
described. 

The  case  should  be  classified,  and  the  variation  of  the  facial  lines 
from  harmony  should  be  studied  in  relation  to  the  occlusion.  The 
etiological  characteristics  in  the  case  should  be  carefully  considered, 
and  an  inquiry  into  the  history  and  habits  should,  by  exclusion,  remove 
any  doubt  as  to  their  signification  in  the  case. 

Mouth-breathing,  especially,  will  be  readily  detected  from  an 
observance  of  the  distortion  of  the  face  and  mouth  peculiar  to  this 
pathological  condition.  The  presence  of  enlarged  tonsils  may  be 
easily  seen  with  the  tongue  depressed  slightly,  and  adenoids  may  be 
felt  with  the  index  finger  carefully  and  quickly  inserted  into  the  throat 
above  the  uvulae.  The  examination  for  adenoids  and  deflected  septa 
and  other  nasal  obstructions  should  be  made  by  the  rhinologist  as 
soon  as  there  is  any  suspicious  indication  of  there  being  such  patho- 
logical conditions  present  in  the  case. 

The  patient's  general  health  should  be  inquired  into,  and  the 
probable  effect  of  any  of  the  infectious  diseases  of  childhood  upon  the 
development  of  the  dental  arches  should  be  noted. 

As  any  diagnostic  interpretation  is  of  value  only  in  so  far  as  it  is  of 
use  in  prognosis,  it  will  be  recognized  that  the  greatest  benefits  to  be 
secured  from  treatment  can  only  be  assured  by  an  intelligent  percep- 
tion of  all  the  etiological  and  pathological  factors  involved  in  the 
case,  no  one  of  which  is  so  obscure  as  not  to  be  considered. 

The  history  of  the  patient,  with  carefully  outlined  subjective  and 
objective  symptoms  of  pathological  significance  should  be  a  matter  of 
careful  detail  and  should  be  recorded  systemically  for  future  reference 
in  the  treatment  of  the  case. 

Fundamental  Pathological  Conditions  in  Malocclusion. — It 
has  been  pointed  out  by  Lischer  that  four  fundamental  pathological 
conditions  conjoin  in  malocclusion,  viz.,  Malposition  of  the  Teeth, 
Malrelation  of  the  dental  arches.  Malformation  of  the  jaws,  and  Malposi- 
tion of  the  Mandible. 

The  first  two  of  these  fundamental  pathological  conditions  are  found 
separately  and  together,  and  form  the  basis  of  the  Angle  classification 


DIAGNOSIS.  651 

of  malocclusion,  which  has  done  admirable  service  as  a  "working 
classification"  for  the  last  fifteen  years. 

As  orthodontia  develops,  it  may  be  necessary  to  provide  a  more 
extensive  classification  to  include  the  jaw  malformations  and  man- 
dibular malpositions,  especially  in  view  of  the  fact  that  the  orthodontic 
or  surgical  treatment  of  some  of  these  more  complex  pathological 
conditions  has  become  more  definitely  established  in  a  small  percentage 
of  favorable  cases. 

Designation  of  Malpositions  of  Individual  Teeth. — ^The 
nomenclature  of  Angle  in  designating  the  malpositions  of  individual 
teeth  is  based  upon  their  deviation  from  the  "line  of  ocdusion^^  which  he 
defined  "as  being  the  line  with  which  in  form  and  position  according  to 
type,  the  teeth  must  be  in  harmony  in  normal  occlusion^ 

According  to  this  nomenclature,  if  a  tooth  is  outside  of  this  line  it 
is  in  labial,  or  buccal  occlusion;  if  inside  of  this  line  it  is  in  lingual 
occlusion;  if  it  is  forward  of  this  line,  it  is  in  mesial  occlusion;  if  in  the 
reverse  direction,  it  is  in  distal  occlusion;  if  rotated  upon  itself,  in  torso- 
occlusion;  teeth  which  have  been  elongated  beyond  normal  relations 
are  in  supra-occlusion;  and  those  which  are  insufficiently  elevated  are  in 
infra-occlusion. 

Malrelation  of  the  Dental  Arches. — ^Under  this  heading  is  in- 
cluded the  mesio-distal  variations  of  the  dental  arches,  and  is  embodied 
in  Angle's  classification  of  malocclusion,  which  represents  three  distinct 
classes,  and  an  occasionally  found  fourth  class. 

Class  I,  Angle's  Classification. — ^To  the  first  class  belong  those 
cases  of  malocclusion  which  are  characterized  by  normal  mesio-distal 
relations  of  the  dental  arches,  with  contracted  and  undeveloped 
maxillary  arches,  especially  in  the  anterior  portion,  in  which  the  teeth 
often  assume  varied  forms  of  individual  malocclusion,  and  often  simu- 
lating in  this  anterior  region,  the  peculiarities  of  Classes  II  and  III, 
both  in  the  occlusion  and  facial  deformity. 

Class  II. — In  the  second  class  of  malocclusion  are  placed  all  those 
cases  in  which  the  lower  dental  arch  is  distal  to  the  upper  on  one  or 
both  lateral  halves,  having  two  divisions  of  bilateral  distal  occlusion,  the 
first  division  being  characterized  by  protruding  upper  incisors,  usually 
mouth-breathers,  and  having  a  subdivision  in  which  the  distal  occlu- 
sion is  confined  to  one  lateral  half,  the  other  half  being  in  normal 
mesio-distal  relations;  the  second  division  having  retruded  upper  in- 
cisors, usually  normal  breathers,  and  its  subdivision  having  the  distal 
occlusion  on  one  lateral  half  of  the  dental  arches  only. 

The  facial  profile  of  a  case  of  the  first  division  of  Class  II  is  usu- 


652  ORTHODONTIA. 

ally  diagnostic  of  the  occlusal  relations,  the  upper  lip  being  short,  and 
revealing  the  protruded  upper  incisors,  and  the  receding  chin  indicat- 
ing the  distal  occlusion.  As  these  cases  are  usually  mouth-breathers, 
the  characteristic  open  drooping  mouth  and  peculiar  tension  of  the 
facial  muscles  is  a  sure  indication  of  naso-pharyngeal  obstruction  of 
present  or  previous  date. 

The  facial  deformity  is  not  so  pronounced  in  the  second  division, 
the  patients  usually  being  normal  breathers,  the  upper  lip  being 
of  proper  length,  but  the  features  disfigured  by  the  receding  chin  and 
lower  third  of  the  face. 

Class  III  is  characterized  by  a  position  of  the  lower  arch  which 
is  mesial  to  the  upper,  with  protruding  lower  incisors,  having  a  division 
in  which  the  mesial  occlusion  is  bilateral  and  a  subdivision  in  which 
the  mesio-distal  relation  to  the  upper  is  normal  in  one  lateral  half 
of  the  lower  arch  and  mesial  to  normal  in  the  other. 

The  facial  profile  is  correspondingly  deformed,  the  chin  being 
prominent,  the  middle  third  of  the  face  undeveloped,  the  angle  of  the 
rami  of  the  mandible  being  more  obtuse  than  normal,  and,  in  some 
cases  of  long  duration,  there  is  scarcely  any  discernible  angle  between 
the  point  of  the  chin  and  the  articular  ends  of  the  condyles.  This 
class  of  cases  would  be  included  under  the  classification.  Malformation 
of  the  Mandible. 

Mouth-breathing  is  frequently  observed  in  Class  III,  and  its  exist- 
ence in  any  case  serves  to  increase  the  inharmonious  lines  of  the  already 
deformed  face. 

Class  rV. — A  very  rare  class,  although  found  to  exist  in  sufficient 
numbers  to  be  worthy  of  record,  and  treatment,  is  Class  IV,  in  which 
the  occlusal  relations  of  the  dental  arches  present  the  peculiar  condi- 
tion of  being  in  distal  occlusion  upon  one  lateral  half,  and  in  mesial 
occlusion  upon  the  other  half  of  the  mouth. 

As  diagnostic  of  these  various  classes,  the  variation  from  the  normal 
mesio-distal  relations  is  usually  best  indicated  by  the  relative  mesio- 
distal  relations  of  the  upper  and  lower  first  permanent  molars  in 
occlusion,  since  they  present  a  history  of  the  longest  lived  occlusion 
during  the  ages  in  which  malocclusion  usually  presents,  and  having 
such  an  important  part  in  the  building  of  the  permanent  dentition  as 
to  be  appropriately  styled  "the  bulwarks  of  the  dental  arches." 

Classification  Chart. — In  order  that  the  principles  upon  which 
this  classification  is  based  may  be  the  more  readily  understood,  the 
author  has  arranged  the  three  common  classes  and  one  rare  class 
in  comprehensive  chart  form  in  Fig.  499,  the  right  and  left  lateral  halves 


DIAGNOSIS.  653 

in  occlusion  being  represented  in  each  section,  with  the  line  of  diagnosis 
intersecting  the  occlusion  of  the  mesio-buccal  cusps  of  the  first  permanent 
molars  of  each  class,  and  illustrating  at  a  glance,  the  deviation  from  the 
normal  mesio-distal  relations  of  each  lateral  half  in  each  class,  division 
and  subdivision. 

The  use  of  the  upper  first  molar  for  the  purpose  of  noting  mesio- 
distal  variation  of  the  lower  dental  arch  presupposes  a  certain  un- 
varying stability  or  a  fixed  position  of  this  tooth  in  relation  to  the 
maxilla  and  the  adjacent  anatomical  regions,  which  might  be  under- 
stood as  being  absolute,  but  such  is  not  the  case. 

Cases  have  been  reported  in  which  the  upper  first  molar  was  mesial 
or  distal  to  its  normal  position  in  the  arch,  although  the  infrequence  of 
these  cases  and  their  observance  only  affects  the  classification  as  far 
as  certain  details  of  the  treatment  is  concerned,  the  main  points  of 
the  treatment  indicated  thereby  being  essentially  unaffected. 

In  simple,  the  indications  for  treatment  as  observed  in  the  chart 
are,  first,  the  restoration  of  normal  shape  and  size  of  the  dental  arches 
in  each  class,  second,  the  restoration  of  the  normal  mesio-distal 
relations  of  the  arches  in  Classes  II,  III,  and  IV. 

Infra-occlusion. — Infra-occlusion,  or  lack  of  occlusion  of  the 
teeth,  is  a  condition  of  abnormal  development  occurring  in  several 
different  forms,  and  more  or  less  common  to  all  classes  of  malocclusion 
requiring  special  description  in  a  classification  based  upon  the  mesio- 
distal  variations  only  of  malocclusion. 

Varying  as  it  does  from  the  slight  infra-occlusion  of  one  or  two 
teeth  to  complex  cases  in  which  the  entire  dental  apparatus  is  involved, 
its  diagnosis,  in  any  extensive  form,  places  the  presenting  case  in  the 
class  of  the  most  difficult  to  treat. 

Associated  as  it  usually  is,  with  mouth-breathing,  the  functions  of 
normal  breathing  must  be  restored  before  treatment  is  successful,  as 
it  is  believed  that  mouth-breathing  is  the  greatest  causative  factor  in 
its  production. 

Add  to  this  the  overdevelopment  of  one  region  and  the  under- 
development of  another  part  in  the  same  maxillary  arch,  and  the 
extent  of  the  abnormal  conditions  present  may  be  understood. 

Variations  of  Infra-occlusion. — Infra-occlusion  occurs  in  several 
forms,  best  described  by  the  designation  of  the  region  in  which  it  is 
observed,  as  infra-occlusion  of  incisors,  cuspids  and  bicuspids,  infra- 
occlusion  of  bicuspids  and  molars,  and  full  bimaxillary  infra-occlusion. 

Infra-occlusion  of  Incisors,  Cuspids,  and  Bicuspids. — By 
far   the    most  common  form  of   infra-occlusion  is  observed  in  the 


654 


ORTHODONTIA. 


CLASS  I 


CLASS  II 
DIV.  1 


CLASS  II 
DIV.  1. 

SUB-DIV. 


CLASS  II 
DIV.  2. 


\ 


LINE  OF  DIAGNOSIS. 


/ 


Fig.  499. — Diagnostic  chart  of  the  mesio  distal  variations  in  malocclusion, 
Based  upon  the  Angle  classification. 


DIAGNOSIS. 


65s 


CLASS  II 
DIV.  2. 
aUB-DlV. 


CLASS  IV 


\ 


LINE  OF  DIAGNOSIS. 


/^ 


Fig.  4v9. — Diagnostic  chan  of  the  mesio-distal  variations  in  malocclusion. 
1  ased  upon  the  Angle  classification. 


656  ORTHODONTIA. 

lack  of  occlusion  of  the  incisors,  cuspids,  and  bicuspids,  sometimes 
including  the  first  and  second  permanent  molars,  varying  usually 
with  the  extent  of  the  mouth-breathing. 

It  is  especially  characterized  by  lack  of  development  of  the  pre- 
maxillary  portion  of  the  arches,  and  oftentimes  overdevelopment  of 
the  posterior  portion  of  the  same  arches. 

Fig.  498  illustrates  an  extensive  case  of  infra-occlusion  extending 
distally  as  far  as  the  molar  region. 

Bilateral  Infra-occlusion  of  Bicuspids  and  Molars. — Exten- 
sive infra-occlusions  involving  the  molars  and  bicuspids  on  one  or  both 
sides,  may  occur  in  any  of  the  various  classes  of  malocclusion.  Fig.  652 
represents  a  case  of  bilateral  infra-occlusion  of  the  molars  and  bicuspids, 
and  in  its  mesio-distal  relations,  it  may  be  classified  as  a  Class  I  case. 


Fig.  500. 

Unilateral  infra-occlusion  0}  molars  and  bicuspids  is  a  condition 
more  commonly  observed  as  the  result  of  arch  mutilation  through 
extraction,  especially  of  the  first  permanent  molars. 

Full  Bimaxillary  Infra-occlusion. — Another  extensive  case  of 
infra-occlusion,  involving  all  of  the  teeth  of  both  arches,  described  by 
Case,*  is  worthy  of  especial  notice,  as  requiring  special  classification. 

As  seen  in  the  cast  on  the  right  of  the  cut,  Fig.  501,  the  teeth, 
anteriorly  and  posteriorly,  are  very  much  too  short  in  relation  to  the 
plane  of  occlusion,  although  being  comparatively  normally  related 
mesio-distally,  and  the  arches  quite  fully  developed  and  of  normal 
shape.     When  the  jaws  are  closed,  as  in  the  model  on  the  left  of  this 

*  Dental  Cosmos,  for  December,  1905,  page  141 1. 


DIAGNOSIS.  657 

figure,  the  facial  appearance  is  that  of  an  edentulous  mouth,  with  its 
lines  of  senility  caused  by  the  approximation  of  the  nose  and  chin,  and 
the  unnatural  fullness  of  the  lips  and  cheeks,  as  illustrated  in  the  face 
mask  on  the  left  of  the  cut.  The  model  and  face  mask  on  the  right, 
the  normal  pose  of  the  profile,  was  obtained  by  placing  a  piece  of 
modeling  compound  between  the  teeth,  and  the  distance  between  the 
arches  of  teeth  adjusted  until  the  profile  appeared  normal. 

Arch  Predetermination. — An  accurate  conception  of  the  normal 
size  and  shape  of  the  dental  arches  in  malocclusion  is  no  longer  a 
matter  of  guesswork  since  the  mechanically  and  anatomically  recon- 
structed arch  has  been  made  a  possibility  by  the  application  of  the 
laws  of  Bonwill  in  the  synthetic  reproduction  of  the  normal  arch  for 


Fig.  501. 

any  given  case,  as  worked  out  geometrically  by  Hawley,  who  by  a 
reversal  of  the  method  of  triangle  construction  of  Bonwill  has  succeeded 
in  predetermining  the  size  of  the  arch  by  constructing  a  triangle  from  a 
primary  measurement  of  the  arc  of  the  centrals,  laterals  and  cuspids. 

A  scientific  determination  of  the  normal  arch  in  any  case  of  mal- 
occlusion not  only  removes  any  doubt  as  to  the  extent  of  arch  expan- 
sion in  treatment,  but  provides  for  the  establishment  of  the  normal 
function  of  articulation,  which  is  most  important  in  mastication,  and 
preservation  of  arch  integrity,  which  the  construction  from  an  equi- 
lateral triangle,  aided  by  the  relationship  of  length  of  cusps  to  depth 
42 


658 


ORTHODONTIA. 


of  overbite,  and  the  compensating  curves  from  cuspid  to  molars, 
affords  by  the  harmonious  working  of  these  laws. 

Quoting  from  Hawley's  article  on  arch  determination,  the  con- 
struction of  the  triangles  and  reproduction  of  the  normal  arch  for  any 
given  case  is  as  follows: 

Bonwill's  Diagram. — "In  Fig.  502  we  have  Bonwill's  geometrical 
figure,  an  equilateral  triangle,  AFG,  inscribed  within  a  circle,  its  base 
FG  representing  the  distance  between  the  condyles,  which  varies  in 
the  livmg  subject  from  three  to  five  inches.     According  to  his  plan,  in 


>l- 


-B 


E                   -I4 

D 

r  -  ■  ■  -  ->**    A  ^ 

'^^Z 7 

*     ,  -  '„>'^      / 1  * 

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A'    X         '  '  \ 

^\.    ^^^ 

^'     \  /          /    '    ^ 

^\.  /'     ^^ 

/     </t           /     1      \ 

r/^       ""i. 

^                           /    ^                 ^                . 

\         /    \              ^^ 

•                             /        \             /                  ' 

^  /   \ 

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/  \^   \  \          \ 

/    '-'       ^\      ' 

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<    \ 

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1           '         ^                   ^      1     / 

''       \ 

1          '               ^-              \i/ 

'"'     ^»   \ 

/    /             ^~~-V-- 

\   \ 

/   /                       'C 

^v       \ 

1  /                '"^ 

\  \ 

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/    '                                                   ' 

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...  . 1 

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— ---   y^ 

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\                                                 : 

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• 

s                                           • 

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X                                                 • 

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%                                 ' 

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^,                        , 

^^  *  * ' 

Fig.  502. 


artificial  dentures,  the  teeth  are  arranged  with  the  cuspids  and  incisors 
in  the  arc  of  the  circle  AJCH,  the  size  of  which  varies  according  to 
the  teeth  selected  for  the  case,  and  this  selection  is  left  to  the  judgment 
of  the  operator." 

Hawley's  Diagram. — "In  order  to  use  this  principle  in  ortho- 
dontia, where  we  have  the  si/.e  of  the  teeth  given  us,  and  from  their 
widths  the  diameter  of  the  circle  AJCH,  we  must  reverse  the  order  of 
procedure  and  find  a  connecting  relation  between  this  circle  and  the 
equilateral  triangle  AFG,  or  the  circle  within  which  it  is  inscribed. 


DIAGNOSIS. 


659 


This  connection  is  not  described  in  Bonwill's  writings  so  far  as  I  have 
been  able  to  find.  It  is  found  in  the  triangle  EDC,  constructed  with 
its  apex  at  the  point  C,  on  the  diameter  of  the  circle  AJCH,  and  its 
base  tangent  to  the  same  circle  at  A,  the  sides  passing  through  the 
points  J  and  H,  located  on  the  circle  by  the  distance  of  the  radius 
from  A." 

"In  application,  to  construct  the  diagram,  we  take  the  radius  of 
the  circle  AJCH  from  the  combined  widths  of  the  central,  lateral, 
and  cuspid  teeth  shown  at  A'B',  With  this  radius  AB,  upon  the  line 
AC,  which  becomes  the  extended  diameter  of  the  circle,  draw  the 
circle  AJCH,  and  with  the  point  of  the  compass  at  A,  mark  off  the 
radius  upon  the  circumference  at  H  and  J.  We  have  here  the  arc 
of  the  circle  upon  which  the  six  front  teeth  are  to  be  arranged,  but 
know  nothing  of  the  size  of  the  triangle  AFG." 


Fig.  503. 

•'From  C  draw  the  lines  CE  and  CD,  through  H  and  J,  extending 
them  indefinitely  and  draw  a  tangent  to  the  circle  A,  cutting  these  lines 
at  E  and  D,  and  forming  an  equilateral  triangle  ECD.  Take  one  side 
of  this  triangle  as  a  radius,  and  with  one  point  of  the  compass  at  A, 
and  the  other  upon  the  extension  of  the  diameter  at  I,  describe  the 
large  triangle  AFG.  Then  draw  the  lines  FJ  and  GH,  and  we  have 
the  desired  diagram  or  arch  upon  which  we  may  measure  off  the 
teeth  with  the  width  as  found  in  the  mouth." 

Fig.  501  represents  the  upper  arch  of  teeth  drawn  in  position  on 
the  predetermined  arch,  after  their  mesio-distal  diameters  had  been 
measured  off  from  each  side  of  the  median  line. 

The  Simplified  Method. — Although  this  gives  a  very  graphic  idea 
of   the  normal  arch  for  a  given  case,  Hawley's  second    method   is 


6o 


ORTHODONTIA. 


more  practical  because  of  its  not  requiring  special  artistic  ability  in 
drawing,  and  but  a  short  time  is  needed  to  complete  it. 

The  line  drawing  of  the  predetermined  arch  is  transferred  to  a 


Fig.  504. 

piece  of  transparent  celluloid,  and  by  placing  this  in  position  over  the 
occlusal  surfaces  of  the  teeth  of  an  upper  or  lower  cast  of  the  case 
before  treatment,  the  extent  of  expansion,  and  change  in  the  shape  of 
the  arch,  laterally  and  anteriorly,  is  very  plainly  indicated. 


Fig.  505. 

^Fig.  504  represents  the  upper  cast  of  a  case  of  malocclusion  of  Class 
II,  Div.  I,  in  which  it  was  desired  to  determine  the  normal  size  and 
shape  the  arches  of  teeth  should  assume  after  treatment. 


DIAGNOSIS.  66 1 

The  superimposed  diagram  is  seen  upon  the  upper  cast  of  the  case 
before  treatment,  and  indicates  considerable  widening  and  shortening 
of  the  arch. 

Fig.  505  shows  the  same  case  after  treatment,  the  teeth  having  been 
brought  to  the  required  arch.  In  this  case  the  combined  widths 
of  the  central,  lateral,  and  cuspid  were  taken  to  determine  the  selection 
of  the  proper  arch.  In  the  lower  arch  of  this  case,  not  so  much  widening 
was  required  owing  to  the  fact  that  it  has  assumed  a  distal  position. 

Comparative  arch  and  tooth  measurements  in  the  mouth  and  on 
the  diagram  in  the  progress  of  a  case,  will  serve  as  a  constant  guide 
to  the  attainment  of  the  predetermined  arch.  These  measurements 
are  made  with  a  scale  graduated  in  hundredths  of  an  inch,  and  one 
with  specially  fine  points  has  been  adapted  by  Hawley  for  the  pur- 
pose.    (See  Fig.  506.) 


Fig.  506. 

Table  of  Average  Measurements. — So  far,  in  the  use  of  this 
method,  the  measurements  have  been  taken  from  arches  in  which  the 
full  complement  of  permanent  teeth  is  present,  but,  by  means  of  a 
system  of  comparative  tooth  measurements  in  a  large  number  of  cases 
in  which  the  permanent  teeth  are  all  present,  Dr.  Hawley  has  succeeded 
in  formulating  a  table  of  average  measurements,  especially  of  the  cen- 
trals, laterals  and  cuspids,  so  that  by  the  measurement  of  a  single 
central  incisor  in  a  case  in  which  the  permanent  centrals  and  first 
molars  were  the  only  teeth  erupted  of  the  permanent  dentition,  the 
width  of  the  permanent  lateral  and  cuspid  to  be  erupted  later  may  be 
quite  accurately  gauged,  and  consequently  the  arc  of  the  anterior  teeth 
from  which  the  entire  permanent  arch  is  determined. 


662 


ORTHODONTIA. 


Quoting  from  Hawley,  the  method  of  making  these  tables  and 
their  applicability  may  be  more  clearly  shown  as  follows:  "Now, 
if  the  teeth  were  found  in  the  mouth  in  the  same  proportion  in  respect 
to  their  greatest  and  least  width,  that  is,  if  with  a  .31  central,  we  would 
find  a  .19  lateral,  a  .27  cuspid,  a  .27  first  bicuspid,  a  .23  second  bicuspid, 
and  a  .35  molar,  and  so  on  with  each  size  of  central,  we  could  make 
out  the  radius  of  each  size  central,  and  from  these  draw  proportional 
diagrams.  But  such  is  not  by  any  means  the  case,  for,  with  a  .31 
central,  we  often,  in  fact  usually,  find  a  lateral  .26  or  .27,  and  the 
cuspid  may  be  quite  well  up  in  the  scale,  or  we  may  have  a  central 
and  lateral  in  good  proportion  and  the  cuspids  much  larger." 

"In  order  to  discover  the  nature  of  this  variation,  I  selected  from 
the  100  measurements  all  the  cases  of  each  width  of  central,  and  made 
of  each  of  them  a  table." 

"The  number  of  cases  of  each  size  central  was  .31,  fifteen,  .32, 
seven,  .^^,  sixteen,  .34,  sixteen,  .35,  nine,  .36,  fourteen,  .37,  thirteen, 
.38,  five,  and  .39,  two. 

Collecting  each  of  these  sets,  nine  tables  were  made,  each  repre- 
senting the  variation  in  width  of  the  laterals,  cuspids,  bicuspids,  and 
first  molars  in  arches  in  which  the  central  incisors  were  all  of  the 
same  width,  of  which  the  table  below  of  the  .35  central  is  an  example: 


Central 

Lateral 

Cuspid 

1ST  BlC. 

2D  Big. 

1ST   MOLAK 

•35 

.24 

•31 

.27 

.27 

.41 

•35 

.28 

•31 

•29 

•30 

.41 

•35 

•25 

•30 

•25 

•25 

.42 

•35 

.28 

•31 

.28 

27 

.42 

•35 

.27 

•33 

.29 

.29 

•44 

•35 

.24 

.30 

•30 

.28 

.41 

•35 

.28 

•33 

.29 

.26 

.40 

.35 

.26 

.30 

.27 

.27 

•43 

•35 

.27 

32 

•27 

.27 

•41 

Average: 

35 

.27 

•31 

.28 

.27 

.42 

The  average  measurements  of  the  nine  tables  were  then  computed, 
forming  an  average  table  with  centrals  of  varying  width  from  .31  to 
.39,  and  the  average  widths  of  the  other  teeth,  as  in  the  following 
table: 

Cbnt'l    Lateral    Cuspid    ist  Bic.      sd  Bic.      ist  Molar    Radius    Correctbd  radius 


•31 

.26 

.29 

.26 

.26 

•39 

.86 

.86 

•32 

.26 

•30 

.27 

.26 

.40 

.88 

.88 

■33 

.27 

•30 

.28 

•27 

.41 

.89 

.90 

•34 

.28 

•30 

.28 

.28 

.42 

.92 

.92 

•35 

•27 

•31 

.28 

.27 

.42 

•93 

.94 

•36 

.28 

■32 

.28 

.28 

.42 

.96 

.96 

•37 

.28 

•32 

•30 

29 

.42 

•97 

.98 

.3? 

.28 

•34 

.30 

.29 

.44 

100 

100 

•39 

.31 

•34 

•31 

•29 

•44 

104 

102 

DIAGNOSIS. 


663 


The  combined  widths  of  the  central,  lateral  and  cuspid  in  each  one 
of  the  nine  tables,  represent  the  radius  that  may  be  used  for  the 
predetermination  of  the  arch. 

The  Corrected  Radius.— A  corrected  radius  at  the  extreme  right 
of  the  table  is  based  upon  a  uniform  variation  of  .02  of  an  inch  from 
.86  to  102. 

Quoting  again  from  Hawley:  "Now,  taking  these  corrected 
radii,  we  will  get  an  arch  for  each  width  of  central,  and  I  will  propose 
these  as  a  basis  of  diagnosis,  study  and  treatment  of  cases  where  only 
part  of  the  teeth  are  erupted,  or  under  the  age  of  twelve." 

"Or  using  the  radius  in  hundredths  of  an  inch  for  comparison, 
they  may  be  used  as  a  guide  for  all  cases,  for  where  we  can  measure 
all  the  teeth,  we  have  only  to  select  the  diagram  with  the  correct  radius, 
and  measure  in  the  teeih.     Remembering  ihat  these  arches  are  only 


Fig.  507. 

averages,  and  smaller  or  larger  teeth  will  constantly  occur  in  con- 
nection with  the  particular  central,  is  there  any  indication  by  which 
we  can  judge  in  which  direction  this  variation  will  occur,  i.e.,  toward 
smaller  or  larger  teeth  ?  I  think  we  have  this  in  the  first  molar,  and 
this  tooth  is  always  present  at  the  time  of  eruption  of  the  central 
incisor.  As  the  first  molar  varies  up  or  down  from  the  average  width, 
I  believe  the  rest  of  the  teeth  will  vary.  For  instance,  we  will  sup- 
pose we  have  a  case  in  which  the  central  incisor  is  .34  and  the  first 
molar  is  .42.  If  I  had  a  second  case  with  the  same  size  central,  but 
with  the  first  molar  .44,  I  would  presume  that  the  lateral  and  cuspid 


664 


ORTHODONTIA. 


and  all  the  rest  of  the  teeth  would  be  likely  to  be  large,  and  would 
select  the  next  larger  arch.  In  this  way  I  think  we  have  the  key  to  a 
fairly  accurate  judgment  of  the  future  denture." 

"  In  making  up  these  averages,  I  have  tried  to  err,  if  at  all,  on  the 
side  of  the  larger  arch,  believing  if  we  do  get  the  arch  slightly  larger 
than  the  teeth  will  fill,  if  it  is  properly  shaped,  and  the  teeth  are  placed 
in  normal  occlusion,  as  the  excess  will,  at  the  worst,  be  only  a  few 
hundreths  of  an  inch,  the  pressure  of  the  cheeks  and  lips,  the  influence 
of  the  occlusal  planes  and  the  pressure  forward  of  the  second  molar 
in  eruption  will  close  the  spaces." 

In  illustration  of  this  use  of  the  arches,  let  us  take  the  case  of  a 
child  8  years  of  age. 


Fig.  sc8. 


In  Fig.  507  there  are  erupted  of  the  permanent  upper  teeth  only 
the  central  incisors  and  the  first  molars.  The  central  incisors  are  .39 
of  an  inch  wide,  and  as  the  molars  seem  to  be  of  corresponding  size 
we  select  the  arch  marked  central  .39,  or  taking  at  an  average  width  of 
the  lateral  and  cuspid,  radius  102. 

Fig.  508  shows  the  development  that  will  be  necessary,  and  Fig. 
509,  the  finished  case  with  the  teeth  brought  to  the  ideal  arch. 

"  Similar  tables  were  made  for  the  lower  teeth,  and  the  result  makes 
it  evident  that  the  uniformity  of  lower  arches,  drawn  from  the  measure- 
ments of  the  lower  incisors  and  cuspids,  is  not  to  be  depended  upon. 
While  the  lower  bicuspids  and  molars  are  fairly  uniform  in  their 
relation  to  the  upper,  within  the  same  mouth,  the  incisors  and  cuspids 
are  not.     This  lack  of  uniformity  is  probably  compensated  for  in  the 


DIAGNOSIS. 


665 


inclination  of  the  teeth  and  the  overbite I  wish  to  advise  that 

instead  of  drawing  the  lower  arch  from  measurements  of  the  lower 
teeth,  ....  the  radius  for  the  lower  be  taken  from  .13  to  .23  of  an 
inch  shorter  than  the  upper,  depending  within  this  variation  on  the  size 
of  the  teeth  or  the  distance  from  the  line  of  occlusion  to  the  crest  of  the 
buccal  cusps." 

"Fears  have  been  expressed  that,  in  bringing  into  orthodontia 
a  mathematically  and  geometrically  calculated  plan,  we  would  restrict 
or  eliminate  the  feature  of  artistic  judgment,  and  that  the  method 
leaves  no  room  for  the  exercise  of  judgment  in  changing  the  form 
of  the  arch  to  satisfy  the  requirements  of  the  various  types.     These 


Fig.  509. 

fears  or  objections  have  been  due  to  misconception  of  the  elasticity 

of  the  method  in  its  application In  so  far  as  hampering, 

in  any  way,  the  use  of  judgment  in  the  art  requirements  of  orthodontia, 
this  method  lays  down  the  most  valuable  principles,  and  forms  the 
most  important  basis  upon  which  artistic  results  in  orthodontia  must 
be  accomplished;  and  instead  of  restricting  the  variation  of  the  arch 
to  correspond  to  different  types,  it  forms  the  only  safe  guide  for  pro- 
cedure in  such  variation." 

"By  restoring  normal  occlusion,  and  a  form  of  arch  in  harmony 
with  the  size  of  the  teeth,  that  will  admit  the  natural  movement  of 
the  mandible,  we  will  thus,  so  far  as  the  mechanism  is  concerned, 
obtain  the  natural  development  of  the  denture.  And  in  retention, 
we  will  guard  against  any  final  retrogressive  changes  that  might  take 
place,  by  conforming  the  arch  to  the  natural  mechanical  forces  of 
articulation." 


666 


ORTHODONTIA. 


The  pre-deter mined  arch  line,  not  only  accurately  locates  the 
proper  "line  of  occlusion,"  but  enables  one  to  more  exactly  designate 
malpositions  of  the  teeth  in  relation  to  it. 

It  is  true  that  the  line  of  the  pre-determined  arch  is  not  strictly 
conformative  to  type,  but  this  is  unessential,  since  the  typal  form  of 


Fig.  510. 

the  arches  is  best  produced  through  the  attainment  of  the  proper 
working  of  the  mechanics  of  the  laws  of  articulation  from  which  the 
line  of  the  pre-determined  arch  is  derived. 

Radiographic  Diagnosis. — The  use  of  the  Roentgen  rays  has  been 
of  inestimable  value  to  the  orthodontist,  in  enabling  him  to  determine 


Fig.  511. 


Fig.  512. 


the  location  of  unerupted  teeth,  if  present,  as  well  as  the  shapes  of  the 
roots  of  the  teeth  and  their  angles  of  inclination,  diseased  areas,  etc. 

It  is  properly  considered  under  diagnosis,  for  with  such  fore- 
knowledge of  the  anatomical  defects,  if  any,  that  the  radiograph  shows, 
the  operator  is  able  to  progress  with  any  doubtful  case  without  delay, 
or  the  possibility  of  a  mistake  in  treatment  due  to  lack  of  previous 
knowledge  of  the  exact  conditions  present. 


DIAGNOSIS. 


667 


Not  infrequently  is  the  orthodontist  called  upon  to  diagnose 
the  presence  or  absence  of  a  permanent  successor  to  a  deciduous 
tooth,  which  the  radiograph  alone  will 
determine.  Such  a  case  is  seen  in 
Fig.  510. 

The  long  retention  of  the  deciduous 
pre-molars  on  both  lateral  halves  of  the 
arch  caused  some  anxiety  on  the  part 
of  the  family  dentist  in  charge  of  the 
case,  as  he  thought  they  ought  to  be 
extracted  to  allow  the  permanent  suc- 
cessors to  erupt. 


Fig.  513.     (Kells.) 


Fig.  514.     (Kells.) 

An  X-ray  was  secured  of  both  lateral  halves  and  the  radiographs 
(Figs.  511  and  512)  showed  that  the  second 
bicuspids  were  not  present,  having  failed  to 
develop,  and  the  deciduous  molars,  retaining 
their  full  length  of  roots  bid  fair  to  act  as  effi- 
cient substitutes  of  the  absent  bicuspids  for 
many  years. 

Frequently  the  cuspid  will   assume  such  a 
position  in  the  alveolar  process  that  its  proper 

-^ - — J    eru])lion  would  require  surgical  interference,  as 

Fig.  515      (Kells.)        in  Fig.  513. 


668  ORTHODONTIA. 

Fig.  514  represents  the  cast  of  an  upper  arch  in  which  the  cuspid 
is  missing  on  the  right  side,  and  the  space  for  its  eruption  entirely 
closed  up.  The  radiograph  of  this  case,  Fig.  515,  exhibits  the  cuspid 
in  an  unerupted  stage  slightly  lingual  to  its  position,  and  the  indications 
for  its  eruption  into  position  by  opening  up  the  space  for  it  between 
the  lateral  and  first  bicuspid,  are  very  favorable. 

PART   V. 
DYNAMICS  AND  ANCHORAGE. 

Force  and  Resistance. — The  relations  of  force  and  resistance  in 
the  application  of  mechanical  appliances  for  the  correction  of  mal- 
occlusion, and  development  of  the  dental  arches,  represent  the  basic 
factors,  which,  in  the-  attainment  of  desired  results  in  treatment 
in  orthodontia,  must  be  considered  together  in  order  that  they  may  at 
all  times  be  correctly  proportioned  in  respect  to  their  requirements  in 
any  given  case. 

In  the  consideration  of  these  factors,  it  must  be  remembered  that 
applied  force  is  active,  and  to  a  degree  directly  opposed  to  the  other 
factor,  resistance,  which  is  passive  or  latent  energy,  incapable  of  being 
measured,  except  by  the  corresponding  degree  of  active  energy  neces- 
sary to  overcome  it  in  the  applied  force. 

The  application  of  forces  in  orthodontia  is  properly  considered  under 
the  general  head  of  Dynamics ;  the  study  of  the  reaction  or  resistance  to 
these  forces  under  the  common  designation  of  Anchorage. 

DYNAMICS. 

Dynamics  may  be  defined  as  the  action  of  applied  forces  in  the  me- 
chanics of  orthodontia.  Before  considering  the  application  of  these 
forces  it  may  be  well  to  enumerate  the  requirements  of  tooth  movement 
as  indicated  by  the  various  malpositions  of  teeth  or  malocclusion  of  the 
dental  arches. 

Dynamical  Requirements  in  Orthodontia. — ^In  order  to  conform 
to  the  directions  of  growth  in  the  dental  arches  it  is  necessary  that  force 
be  produced  by  appliances  in  the  three  dimensions  of  length,  breadth, 
and  height.  Again,  force-producing  appliances  must  operate  to  pro- 
duce mesial  or  distal  changes  in  occlusion. 

Further,  these  appliances  must  be  capable  of  producing  forces  which 
shall  operate  to  correct  malocclusion  in  the  positions  of  individual  teeth. 

Effect  of  Force  on  Tooth  Movement. — ^The  action  of  force  upon 
the  teeth  is  entirely  dependent  upon  the  magnitude  of  the  force,  and  its 


DYNAMICS  AND  ANCHORAGE. 


669 


direction  as  indicated  by  the  manner  of  its  application.  A  study  of 
the  manner  of  application  of  force  upon  teeth  to  be  moved  will  reveal 
five  distinct  methods  of  tooth  movement,  viz.,  inclination,  bodily,  rotat- 
ing, extruding  and  intruding  movements.* 

Inclination  movement  is  that  action  of  a  force  upon  the  teeth  whereby 
their  crowns  are  tipped  into  new  occlusal  relations. 

An  example  of  inclination  movement  of  a  tooth  is  diagrammatically 
shown  in  Fig.  516,  in  which  the  crown  of  the  incisor  is  moved  from 
A  to  B  the  apex  C  not  being  appreciably  changed  in  position,  except 
through  the  developmental  tendency  increased  by  the  stimulation  of 
treatment. 

Inclination  movement  is  obtained  in  the  incisor  region  by  ligating  the 
teeth  to  the  expansion  arch  as  in  Fig.  560,  and  in  the  molar  region  by  the 
use  of  round  buccal  tubes  on  molar  bands. 


Fig.  517. 


Fig.  518. 


Bodily  movement  is  that  action  of  a  force  upon  the  teeth  whereby  they 
are  moved  bodily  in  the  horizontal  plane. 

This  method  of  tooth  movement  is  illustrated  in  Fig.  516  by  a  force 
acting  equally  at  right  angles  to  the  central  axis  of  a  tooth  changing 
its  position  from  EG  to  JH  an  equal  distance  apicably  and  coronally. 

Bodily  movement  is  secured  in  the  incisor  region  by  the  use  of  ver- 
tical rods  fitting  into  tubes  (Angle)  on  the  incisor  or  bicuspid  bands  as 
in  Fig.  610,  or  by  the  use  of  compensating  double  expansion  arches 
(Fig.  543)  (Case).  In  the  molar  region  bodily  movement  is  secured 
by  the  use  of  buccal  tubes  which  do  not  allow  of  rotation  of  the 
expansion  arch  as  in  Fig.  547. 

Rotating  movement  of  the  teeth  is  that  action  of  a  force  upon  the  teeth 
whereby  they  are  rotated  upon  their  central  axes. 

This  movement  of  teeth  is  illustrated  in  Fig.  518  by  a  force 
acting  in  the  horizontal  plane  tending  to  turn  the  tooth  on  its  central 
axis  from  f  to  d. 

*  The  author  has  adopted  these  terms  of  Case  because  of  their  simplicity  and  exactness 
n  nomenclature 


670 


ORTHODONTIA. 


Extruding  movement  is  that  action  of  a  force  upon  the  teeth  whereby 
they  are  moved  coronally  in  the  line  of  their  central  axes. 

In  Fig.  519  this  action  of  a  force  L  upon  a  tooth  is  indicated  by  its 
movement  from  R  to  T  in  the  vertical  plane. 

Intruding  movement  is  that  action  of  a  force  upon  the  teeth  whereby 
they  are  moved  apicably  in  the  line  of  their  central  axes. 


-^ 


Fig.  519.  Fig.  520.  Fig.  521. — {Guifford.) 

This  action  of  a  force,  being  the  reverse  of  extrusion,  is  indicated  in 
Fig.  520  by  a  force  N  directed  apicably,  causing  the  tooth  to  move  from 
E  to  D  in  the  vertical  plane. 

Elementary  Force-producing  Machines. — ^The  forces  required  for 
tooth  movement  which  have  been  found  most  adaptable  to  the  condi- 
tions in  the  mouth,  are  embodied  in   the  principles  of  the  following 

simple  machines: the  inclined  plane, 
the  screw,  the  spring,  the  lever,  and 
the  wheel  and  axle.  Auxiliary 
forces  are  obtained  from  the  elastic- 
ity of  rubber,  the  contraction  of 
moistened  silk,  and  the  elasticity 
of  stretching  of  soft  wire. 

The  Inclined  Plane. — The  in- 
clined plane,  in  simple,  as  shown  in 
Fig.  521,  is  seldom  used  at  this  day  as 
an  independent  force  principle,  on  ac- 
count of  its  relative  inefficiency.  Its 
action  is  dependent  entirely  upon  the 
closing  of  the  teeth  together  firmly 
in  occlusion,  and  as  soon  as  the  teeth  become  tender  from  this  pres- 
sure, the  action  of  the  occluding  force  is  voluntarily  withdrawn. 

However,  in  combination  with  other  forces  such  as  the  use  of  inter- 
maxillary force  in  connection  with  the  inclined  plane  as  m  Fig.  663,  the 
force  of  the  inclined  plane  has  a  definite  value. 

The  Screw. — ^The  screw  is  a  modified  inclined  plane,  and  its  power 
being  under  the  control  of  the  operator,  is  direct  and  positive.     There 


Fig.  52: 


DYNAMICS  AND  ANCHORAGE.  67 1 

are  several  forms  of  appliances  in  which  the  principle  of  the  screw  is 
used  in  orthodontia;  viz.,  the  jackscrew,  the  traction  screw,  and  the 
expansion  arch. 

The  jackscrew  is  shown  in  Fig.  522  in  two  forms,  A  and  B.  The 
original  form  A  has  fallen  into  disuse  because  of  its  faulty  anchorage,  the 
fish-tail  end  being  intended  to  rest  against  the  lingual  surface  of  an 
unhanded  tooth,  or  in  a  groove  cut  in  the  enamel,  both  of  which  proced- 
ures are  contraindicated  in  modern  practice.  The  form  B,  having  a 
right-angled  end  which  engages  with  a  short  horizontally  or  vertically 
placed  tube  on  a  cemented  band,  is  the  more  efl&cient  form  of  jackscrew 
used  at  the  present  time.  It  operates  in  the  direction  of  length  only, 
exerting  a  pushing  force  as  indicated  by  the  double  arrow. 

The  traction  screw  C,  as  improved  by  Angle,  exerts  a  pulling 
instead  of  a  pushing  force  as  shown  in  Fig.  522,  and  is  used  either  alone 
or  in  combination  with  the  expansion  arch. 

The  arrows  indicate  the  only  possible  direction  in  which  it  exerts 
force,  parallel  to  its  length,  hence  its  use  is  limited  to  closing  up  spaces 
between  teeth,  or  in  moving  a  tooth  of  lesser  resistance  toward  a  tooth 
of  greater  resistance. 


Fig.  523. 

The  threaded  expansion  arch  embodies  the  screw  principle  in  com- 
bination with  the  spring  and  lever  as  described  under  Dynamics  of  the 
Expansion  Arch. 

The  Spring. — The  forces  exerted  by  the  spring  are  forces  of  elas- 
ticity, and  are  exhibited  in  so  many  of  the  different  forms  of  modern 
appliances  that  their  analysis  is  of  especial  importance.  The  forms  of 
elasticity  of  the  spring  are  of  two  kinds,  the  elasticity  of  flexion,  or  bend- 
ing, and  the  elasticity  of  torsion,  or  twisting. 

Elasticity  of  Flexion  is  the  tendency  of  a  spring  wire  to  return  to 
its  original  form  after  bending. 

This  form  of  elasticity  is  shown  in  Fig.  523  by  a  spring  wire  AC, 
which,  when  its  ends  are  held  between  the  thumb  and  finger  may  be 
bent  in  the  arc  DE,  and  upon  releasing  the  pressure,  will  quickly  return 
to  its  original  form  AC. 

This  force  of  elasticity  in  the  spring  is  taken  advantage  of  in  the 
expansion  arch,  and  in  the  elastic  lever. 


672 


ORTHODONTIA. 


Elasticity  of  Torsion  is  the  tendency  of  a  spring  wire  to  untwist  after 
torsion  (similarly  to  the  untwisting  of  a  rubber  tube  after  being  twisted 
lengthwise). 

The  elasticity  of  torsion  may  be  illustrated  in  the  outward  twist  that 
is  given  to  the  end  of  an  arch  wire,  Fig.  524,  so  that  when  inserted  in  the 
vertical  tube,  it  will  tend  to  move  the  root  of  the  tooth  to  which  it  is 
attached  in  the  arc  of  a  circle. 


Fig.  524. 


Fig.  525. 


This  principle  is  also  used  in  the  torsion  of  the  base  wire  on  both  sides 
of  la  pin  on  the  middle  section  of  the  new  Angle  appliances,  as  in 
Fig.  525,  the  effect  being  to  change  the  angle  of  the  pin  from  H  to  I, 
to  effect  the  outward  movement  of  the  root  of  a  tooth. 

This  torsion  may  be  obtained  through  the  use  of  two  pairs  of 
pliers  shown  in  Fig.  526,  or  through  the  use  of  torsion  pliers  designed  by 
the  author  for  the  purpose,  and  shown  in  Fig.  527.     The  plier  B  with  the 


Fig.  526.     (Young.) 

slotted  end  is  used  to  grasp  the  base  wire  de  firmly,  and  the  plier  A  to 
twist  the  base  wire  on  each  side  of  the  upright  pin  within  the  divided  nose 
of  plier  B.  A  slight  circular  motion  is  given  to  the  plier  A  and  the  wire  at 
the  base  of  the  pin  is  twisted,  thus  giving  the  pin  a  new  angle  of  inclination. 
The  Lever. — ^The  force  of  the  lever  is  one  of  the  most  common  in 
use  in  orthodontia.  In  combination  with  the  spring  of  the  expansion 
arch  or  with  spring  wires  of  other  sorts  it  has  a  definite  force  value.  Its 
form  as  a  spring  lever  for  rotation  of  individual  teeth  in  connection  with 
the  expansion  arch  is  shown  in  Fig.  606.     The  ends  of  the  lever  fitting 


DYNAMICS   AND    ANCHORAGE. 


673 


in  the  square  tube  on  the  band  of  the  tooth  to  be  rotated  should  be 
square  so  as  not  to  allow  of  any  turning  of  the  lever  within  the  tube. 
The  other  end  of  the  lever  should  be  bent  into  the  shape  of  a  hook  to 
engage  with  the  expansion  arch  as  shown  in  Fig.  528. 

d 


B 


Fig.  527. 

The  Wheel  and  Axle. — ^The  principle  of  the  wheel  and  axle  is  in 
common  use  in  orthodontia  in  the  ligating  of  teeth  for  rotation.     This  is 
diagrammatically  shown  by  the  arrangement  of  the  slip  noose  ligature  in 
Fig.  529.     The  point  of  application  is  represented  by  the  end  of  the  slip 
noose  on  the  lingual  side  of  a  tooth,  the  ends  being  ^ 
ligated  to  the  expansion  arch.     The  force    exerted 
by  the  contraction  of  the  silk  ligatures  is  in  the  direc- 
tion of  the  arc  of  a  circle,  or  in  effect  the  same  as  if    ^ 
applied  to  the  crown  (wheel)  and  exerted  upon  the  Fig.  528. 

smaller  diameter  (axle)  of  the  root. 

The  same  principle  is  utilized  with  the  wire  ligature  attached  to  a 
ingual  spur  on  an  incisor  band. 

The  Elasticity  of  Rubber. — The  force  produced  by 
rubber  in  the  movement  of  teeth  is  due  to  its  elasticity, 
which  is  exerted  in  two  ways,  by  compression,  and  by  trac- 
tion, or  pulling.  Elasticity  of  compression  is  produced 
by  the  rubber  wedges  placed  between  the  expansion  arch 
and  the  mesial  or  distal  angles  of  incisors  to  assist  in  rota- 
tion. 

The  elasticity  of  traction  is  exemplified  in  the  use  of 
elastic  rubber  rings  for  producing  either  interdental,  intermaxillary,  or 
occipital  force. 

'Interdental  elastic  force  is  a  term,  coined  by  the  author,  to  desig- 
43 


Fig.  529. 


674 


ORTHODONTIA. 


nate  the  force  of  elastic  rubber  rings  used  between  teeth  in  the  same 
dental  arch  as  illustrated  in  Fig.  530. 

Intermaxillary  Force  is  the  commonly  used  term  to  designate 
the  use  of  the  elastic  force  of  rubber  rings 
between  teeth  of  opposing  dental  arches. 

Its  use  varies  from  the  simple  extrusion 
of  an  incisor  to  the  mesio-distal  shifting  of 
the  occlusion  of  the  teeth  of  both  dental 
arches. 

Fig.  531  illustrates  its  use  in  the  bucco- 
lingual    shifting    of    the    occlusion  of  the 


Fig.  530. 


Fig.  531. 


molars.     In  Fig.  650  it  is  applied  at  a  number  of  points  along  the  line  of 
the  arch  for  correcting  infra-occlusion. 

Its  further  use  in  reenforcement  of  anchorage  is  shown  in  Fig.  555. 


Fig.  532. 

For  shifting  the  occlusion  antero-posteriorly,  it  is  applied  as  at  C, 
or  Class  II,  and  as  at  D  for  Class  III,  Fig.  532,     Occasionally  it  is 


Fig.  533.  Fig.  534. 

applied  across  the  front  of  the'dental  arches  as  in  Fig.  533  when  a 
mesial  or  distal  force  is  required. 

Occipital  force  isobtained  by  theuse  of  heavy  elastic  bands  attached 


DYNAMICS  AND  ANCHORAGE. 


67s 


from  the  headgear  to  the  ends  of  a  labial  traction  bar,  which  is  attached 
to  the  expansion  arch  on  the  teeth  as  in  Fig.  534. 

Contraction  of  Moistened  Silk. — ^The  force  obtained  by  the  con- 
tractile quality  of  silk  cord  in  the  mouth  is  taken  advantage  of  in  the  use 
of  silk  ligatures  for  the  movement  of  the  incisors  and  cuspids.     They  are 


Fig.  535. 

especially  valuable  in  rotation  of  teeth  using  the  principle  of  the 
wheel  and  axle  as  in  Fig.  529. 

Elasticity  of  Stretching  of  Soft  Wire. — By  pinching  a  section  of 
soft  wire  attached  between  two  teeth  the  reciprocation  of  movement  of 
which  is  desired,  the  wire  is  stretched  so  that  it  exerts  a  gentle  force  in  the 


directions  of  its  extremities.  Fig.  738  illustrates  a  pinched  wire 
attached  to  the  bands  of  two  cuspids  for  slight  expansion  of  the  arch. 
Fig.  535  exhibits  the  Angle  wire  stretching  plier  designed  for  use  in  such 
cases. 


676 


ORTHODONTIA. 


Dynamics  of  the  Expansion  Arch. — ^The  inherent  forces  of  the 
expansion  arch,  Fig.  536,  are  the  forces  of  the  spring,  the  screw,  and 
the  lever.  The  auxiliary  forces  to  the  expansion  arch,  which  with  the 
inherent  forces  give  it  the  greatest  range  of  usefulness  of  any  known  ap- 
pliance, are  the  forces  of  the  elasticity  of  rubber,  and  the  contraction  of 
moistened  silk. 


Fig.  537- 

The  most  important  of  the  inherent  forces  of  the  expansion  arch  is  the 
elastic  force  of  the  spring,  the  principles  of  the  screw  and  lever  being 
secondary  to  the  main  force  of  elasticity.  The  principle  of  elasticity,  as 
related  to  the  expansion  arch,  is  its  tendency  to  return  to  its  original 
form  of  a  straight  wire  after  bending,  thus  producing  forces  of  various 
degrees  of  intensity  according  to  the  diameter  of  the  spring  wire,  and 
the  material  from  which  it  is  constructed. 


rit^.=^. 


IW'''-'-'^'^' 


-^ijiiiiuillhiinpST' 


=D 


Fig.  538. 

Gauge  of  Expansion  Arch  as  Related  to  Elasticity. — ^The  elas- 
tic qualities  of  the  narrower  gauges  of  expansion  arches,  as  for  example, 
the  .30  inch  arch,  can  be  utilized  to  much  better  advantage  than  those 
of  larger  diameter,  since,  while  they  are  in  reality  no  more  elastic,  yet 
.  the  elastic  force  is  more  readily  available  for  use  with  delicate  ligatures. 
.  In  this  connection  it  will  be  observed  that  the  choice  of  a  metal  or 
alloy  which  is  the  most  elastic,  and  which  undergoes  no  chemical  change 


DYNAMICS   AND   ANCHORAGE. 


677 


in  the  mouth,  as  gold,  platinum  and  their  alloys,  is  of  special  value  in  an 
expansion  arch  for  upon  these  qualities  depend  the  efficiency  of  the 
appliance. 

Production  of  Force  in  Three  Dimensions  with  the  Expansion 
Arch. — In  the  drawing  of  the  expansion  arch  in  Figs.  537  and  538, 
it  may  be  observed  that  force  may  be  produced  with  it  in  both  the 
horizontal,  and  vertical  planes  by  the  use  of  the  spring  and  screw 
power.  The  dental  arch  may  thus  be  lengthened,  widened,  and  de- 
veloped vertically  corresponding  to  the  natural  directions  of  development 
in  three  dimensions  of  space  with  the  expansion  arch,  utilizing  forces 
which  can  always  be  under  the  control  of  the  operator. 

Dynamics  of  the  Divided  Expansion  Arch. — ^The  principle  of  the 
divided  expansion  arch.  Fig.  539,  depends  on  the  use  of  an  extra  set  of 


Fig.  539. 

jackscrews  inserted  in  the  center  of  the  arch.  This  style  of  arch  has 
the  power  of  four  jackscrews,  and  at  the  same  time  retains  much  of  the 
elasticity  of  the  plain  expansion  arch.  It  can  be  made  to  exert  force  in 
the  directions  of  the  arrows  in  Fig.  539.  Its  especial  advantage,  how- 
ever, is  in  the  positive  lateral  force  exerted  by  the  central  screw  when 
the  nuts  are  turned  up  against  the  central  tube. 

Dynamics  of  the  Sectional  Arch. — ^The  sectional  arch  was  devised 
by  Angle  for  the  delivery  of  force  for  bodily  movement  of  teeth.  It 
is  diagrammatically  shown  in  Fig.  540,  in  which  it  will  be  observed  that 
without  the  upright  pins  C,  D,  etc.,  it  is  similar  to  a  plain  expansion 
arch  of  small  diameter,  except  for  the  middle  section  being  removable 
from  the  end  sections  at  A  and  B.  It  is  possible  to  deliver  force  from 
it  in  the  directions  of  the  arrows  L,  M,  N,  O,  K,  and  in  various  inter- 
mediate directions,  similarly  to  the  delivery  of  force  by  the  plain  arch. 


678 


ORTHODONTIA. 


but,  in  the  use  of  the  soldered  upright  pins  C,  D,  etc.,  the  character  of 
the  force  delivered  is  changed  from  inclination  to  bodily  movement. 
The  turning  up  of  the  nuts  on  the  end  sections  delivers  force  to  the 
middle  section,  which  is  transmitted  uniformly  to  the  upright  pins 
in  the  same  horizontal  plane,  and  these  pins,  being  attached  to  vertical 


Fig.  540. 

tubes  on  incisor,  cuspid,  or  bicuspid  bands,  move  these  teeth  bodily 
forward  or  outward  in  line  with  the  delivered  force. 

By  bending  the  pins  or  twisting  the  base  wire,  the  pins  may  be  made 
to  exert  force  in  an  arc  tending  to  move  the  apical  end  of  the  tooth  in 
the  same  arc. 

The  difference  in  the  manner  of  delivery  of  the  force  between  the 
plain  arch  and  the  sectional  arch  is  seen  in  Fig.  541,  the  crown  of  the 


Fig.  542. 


tooth  on  the  left,  being  ligated  to  the  plain  arch,  is  being  moved  by 
inclination  movement,  in  the  direction  of  the  arrow  H,  the  apex  I 
remaining  in  the  same  relative  position;  the  tooth  on  the  right,  being 
attached  by  the  vertical  tube  and  pin  to  the  sectional  arch,  is  being 
moved  bodily  in  the  direction  of  the  arrows  E  and  F,  the  apex  of  the 
roof  moving  equally  as  fast  as  the  crown. 


DYNAMICS   AND    ANCHORAGE.  679 

Economy  of  Force  with  Sectional  Arch. — On  account  of  the  in- 
creased resistance  to  tooth  movement  when  moved  bodily  than  when 
moved  by  inclination,  it  is  necessary  to  conserve  all  of  the  delivered 
force  by  attaching  the  vertical  tubes  as  near  the  gingivae  as  possible,  thus 
lessening  the  resistance  to  bodily  movement  as  in  Fig.  542,  B  showing  an 
improperly  placed  tube,  and  F,  a  correctly  placed  tube  on  an  incisor 
band,  fitted  close  to  the  gingiva.  A  very  ingenious  recording  instru- 
ment, or  *' archograph,"  has  been  invented  by  Strang  for  measuring 
and  recording  the  delivery  of  force  by  the  sectional  arch. 

Dynamics  of  the  Double  Expansion  Arches. — ^The  principle  of 
the  double  reciprocating  expansion  arches,  which  was  first  illustrated 
and  described  by  C.  S.  Case,  presents  an  unique  and  economical 
method  of  applying  force  for  bodily  movement  of  the  teeth,  although  the 


Fig.  543. 

apparatus  is  considerably  less  delicate  than  the  sectional  arch  of 
Angle.  The  power  arch,  in  Fig.  543,  delivers  force  to  the  "rigid 
rootwise  extension,"  and  the  fulcrum  arch  exerts  a  traction  force 
lingually  upon  the  edge  of  the  incisor  in  the  direction  of  the  molar 
anchorage,  where  these  forces  are  neutralized,  if  equal.  The  result  of 
this  reciprocation  of  force  and  its  application  tend  to  move  the  root  of 
the  incisor  labially,  while  the  crown  is  moved  lingually,  or  prevented 
from  moving  forward. 

ANCHORAGE. 

A  Study  of  Resistance  Values. — Anchorage  deals  entirely  with 
the  factor  of  resistance  to  applied  force  in  orthodontia,  and  in  its  con- 
sideration the  resistance  values  of  the  teeth,  singly  and  collectively,  their 
location,  size,  and  number  of  roots,  their  lesser  resistance  to  mesial  than 
to  distal  movement,  the  relative  thickness  of  the  alveolar  process,  and 
the  varying  degrees  of  its  density  according  to  age,  must  all  be  taken  into 
account.  Anchorage  is  thus  a  question  of  comparative  resistance 
values  of  the  teeth,  singly  or  in  combination. 

Resistance,  although  latent,  is  nevertheless  energy,  and  the  degree 
of  one's  success  in  the  restoration  of  harmony  in  occlusion  and  facial 


68o  ORTHODONTIA. 

lines  is  to  a  great  extent  dependable  upon  the  intelligent  use  of  this  inert 
energy,  which  should  always  be  accurately  proportioned  to  the  dynam- 
ical requirements  in  dental  arch  development. 

In  regard  to  the  mechanical  requirements  of  anchorage,  ihe  limi- 
tations in  the  quality  and  quantity  of  the  applied  force,  because  of 
the  danger  of  injuring  the  living  tissues  involved,  present  a  striking 
contrast  to  the  application  of  similar  forces  in  the  field  of  general  mechan- 
ics where  resistance  may  be  accurately  measured  and  scientifically 
adjusted  so  that  its  stability  in  relation  to  any  dynamical  requirements 
may  always  be  positively  known. 

In  the  field  of  applied  mechanics  in  the  arts,  for  example,  a  force 
acting  against  an  unstable  resistance  is  not  considered  within  the  limits 
of  practicability,  but  in  the  application  of  dynamics  to  living  dental  and 
alveolar  tissues,  the  mechanical  problems  in  the  development  of  the  den- 
tal arches  and  correction  of  malocclusion  are  not  infrequently  solved  by 
the  operation  of  a  force  acting  from  a  more  or  less  unstable  base. 

Thus  it  often  happens  that  the  resistance  to  tooth  movement  may  be 
located  in  a  single  anchor  tooth,  which  is  antagonizing  the  delivery 
of  a  force  in  another  part  of  the  arch,  and  is  itself  being  moved  at  the 
same  time  in  a  direction  in  line  with,  or  at  opposing  angles  to  the  direc- 
tion of  the  applied  force. 

Anchorage  is  the  resistance  selected  as  a  base  from  which  force  is  to 
he  delivered  for  the  movement  of  teeth. 

This  resistance  may  be  obtained  from  the  teeth  singly,  or  in  multi- 
ple, or  from  the  top  and  back  of  the  head  by  means  of  the  headgear,  and , 
except  in  reciprocation  of  anchorage,  should  always  be  greater  than  the 
force  to  be  delivered  from  it  in  the  movement  of  teeth. 

The  stability  of  teeth  used  for  the  anchorage  appliance  varies  with 
their  power  of  resistance,  which  is  determined  by  their  size  and  loca- 
tion, the  length  and  number  of  their  roots,  and  the  direction  and  manner 
of  application  of  the  required  force,  as  well  as  the  period  of  development 
of  teeth  and  process. 

From  the  size  and  number  of  their  roots  and  advantageous  location 
in  the  posterior  part  of  the  arch,  the  molars  are  most  commonly  selected 
as  anchor  teeth. 

First  Molar  Anchorage. — The  first  molar  is  so  often  chosen  as 
an  anchor  tooth  for  the  basal  attachment  of  appliances  in  the  correc- 
tion of  malocclusion,  because  of  certain  anatomical  and  mechanical 
features  that  enter  into  the  selection  of  an  efficient  anchor  tooth. 

At  six  or  seven  years  of  age,  the  first  permanent  molar  is  usually  in 


DYNAMICS   AND    ANCHORAGE.  68 1 

position,  and,  as  its  name  implies,  is  the  only  permanent  molar  ready 
to  be  used  as  an  anchor  tooth. 

If  the  relations  of  these  teeth  are  incorrect  with  their  mates  in  the 
opposite  arch,  it  is  to  them  that  attention  has  to  be  first  directed  and 
their  relative  positions  corrected  and  retained  until  occlusion  of  enough 
of  the  permanent  teeth  has  been  established  to  secure  the  normal  rela- 
tionship of  the  arches  as  a  whole. 

Again,  later  in  life,  when  the  second  molars  have  erupted,  the  use 
of  the  first  permanent  molar  as  an  anchor  tooth  receives  an  efficient 
re-enforcement  to  its  resistance  to  tooth  movement  anteriorly,  from  the 
fact  of  its  being  supported  by  the  second  molar  and  the  strong  alveolar 
process  surrounding  it. 

The  roots  of  the  first  molar  are  also  more  diverging  than  those  of 
the  second,  so  that  the  first  molar  has  a  greater  comparative  resistance 
value  than  the  second  molar  because  of  the  greater  force  required  to  dis- 
place it. 

The  eruption  of  the  third  molar  adds  still  greater  resisting  power 
in  movement  of  teeth  anteriorly  to  the  first  molar  as  an  anchor  tooth. 

Up  to  this  point,  anchorage  has  been  treated  from  its  physical  aspect 
only,  i.e.,  from  a  study  of  the  varying  degrees  of  resistance  of  the  teeth 
themselves  and  the  structures  in  which  they  are  imbedded. 

Mechanical  Requirements  of  Anchorage. — A  further  considera- 
tion of  the  subject  reveals  another  feature  of  importance,  viz.,  the 
mechanical  requirements  of  anchorage,  which  has  to  do  entirely  with 
the  attachments  to,  and  arrangement  of,  the  appliances  upon  the 
teeth  for  the  delivery  of  force. 

The  necessity  for  the  securing  or  anchoring  of  a  force  appliance  in 
the  mouth  so  that  the  force  can  be  effectively  and  continuously  utilized 
has  given  rise  to  the  following  fundamental  principle  relating  to 
stability  of  appliances  and  their  attachments. 

The  Principle  of  Fixation. — The  general  condition  of  stability, 
or  fixedness,  in  an  appliance,  or  the  summing  up  of  all  mechanical 
principles  which  refer  to  stability,  may  be  described  in  comprehensive 
terms  as  the  principle  affixation. 

This  principle  of  fixation  refers  to  stability  in  anchorage  attach- 
ments, to  approximately  stable  attachments  upon  teeth  to  be  moved, 
and  thereby  to  the  direction  and  control  of  forces  used  in  tooth 
movement. 

A  '^fixed^^  appliance,  then,  is  one  which  in  its  construction  takes 
advantage  of  every  applicable  principle  of  mechanics  to  prevent  insta- 
bility in  the  delivery  of  force  for  tooth  movement. 


682 


ORTHODONTIA. 


In  the  observance  of  the  principle  of  fixation  in  the  construction  and 
attachment  of  appliances  to  the  teeth,  the  proper  relation  between 
force  and  resistance  is  always  obtained.  In  every  appliance  there  must 
be  an  adequate  force  principle  and  a  resistance  quality  in  the  anchorage 
suflScient  to  act  as  a  stable  base  for  the  operation  of  the  force. 

The  laws  of  action  and  reaction  govern  the  application  of  force 
appliances  to  the  teeth,  and  a  failure  to  observe  their  requirements  in  the 
securing  of  sufficient  anchorage  resistance  for  any  tooth  movements  will 
result  in  the  dangerous  tipping  and  displacement  of  the  anchor  teeth  in 
some  cases. 

A  simple  illustration  of  the  primary  relation  between /or ce  and  resist- 
ance, as  represented  by  the  laws  of  action  and  reaction  in  the  use  of  the 


"]^=  aooolbjs. 


Fig.  544. 

jackscrew  for  raising  a  house,  may  serve  to  fix  the  underlying  mechanical 
principle  more  firmly  in  one's  mind. 

If  the  jackscrew,  Fig.  544,  is  to  lift  a  weight  of  3000  pounds  as 
represented  by  ihe  weight  of  the  sill  of  a  house  in  one  section  under  which 
pressure  is  applied,  the  force  represented  by  the  arrow  will  be  exerted  in 
the  direction  of  the  load  as  well  as  in  the  opposite  direction,  and  if  a  sub- 
stantial base,  offering  sufficient  resistance  to  the  load,  is  not  provided, 
the  exertion  of  the  force  will  cause  the  jackscrew  to  break  through  the 
foundation  instead  of  lifting  the  load. 

It  is  evident  from  this  illustration  that  the  basal  resistance  must  be 
greater  than  the  load  in  order  for  the  jackscrew  to  have  the  desired 
effect  of  raising  the  house. 

In  the  application  of  force  to  the  teeth,  the  very  nature  of  the  com- 
paratively unstable  quality  of  the  tissues  in  which  the  teeth  are  imbedded 
makes  it  impossible  to  consider  stability  as  an  absolute  factor  in  anchor- 


DYNAMICS  AND  ANCHORAGE.  683 

age.  Hence,  in  the  definitions  of  various  forms  of  anchorage,  stability 
of  resistance  must  be  regarded  as  relative  but  as  near  the  absolute  as  the 
conditions  will  allow.  The  following  definitions  of  the  various  forms 
of  anchorage  are  based  upon  the  principles  of  anchorage  as  described 
by  Angle. 

Simple  anchorage  is  the  obtaining  of  a  sufficient  resistance  in  one 
part  of  the  arch  for  tooth  movement  in  another  part  of  the  same  arch,  the 
anchorage  resistance  being  relatively  greater  than  that  of  the  teeth  to  be 
moved,  although  admitting  of  some  instability  of  the  anchor  teeth. 

An  illustration  of  simple  anchorage  is  shown  in  the  relatively  greater 
resistance  of  the  molar  teeth  in  Fig.  545,  as  anchorage  for  the  movement 
of  the  incisors,  on  account  of  the  molars  having  several  roots  and  being 
imbedded  more  firmly  in  the  bony  tissues  than  the  incisors.  In  inclina- 
tion movement  of  the  incisors,  this  form  of  simple  anchorage,  while  allow- 
ing a  slight  tipping  of  the  anchor 
teeth  in  some  cases  in  which 
alternate  periods  of  rest  and  re- 
newed operation  of  the  appliance 
permits  the  anchor  teeth  to  settle 
back  into  their  normal  positions, 

is   usually  considered  adequate 

.  Fig.  545. 

for  the  purpose,  but  m  inclina- 
tion movement  of  a  greater  number  of  teeth  including  the  cuspids,  or 
in  the  bodily  movement  of  the  incisors,  considerable  re-enforcement  of  a 
simple  anchorage  is  necessary. 

Stationary  anchorage  represents  an  anchorage  which  is  stable  and 
unvarying  in  its  resistance  for  tooth  movement. 

Although  stationary  anchorage,  in  the  absolute,  is  probably  seldom 
obtained  in  any  of  the  combinations  for  re-enforcement  of  a  simple 
anchorage,  yet  an  absolutely  stationary  anchorage  is  so  nearly  seciured  in 
many  cases  that  to  all  intents  and  purposes  the  anchorage  may  be  con- 
sidered as  stationary. 

Re-enforced  anchorage  is  the  adding  of  the  resistance  of  teeth  in  the 
same  arch  or  opposite  arch,  through  the  use  of  other  forms  of  anchorage,  as 
auxiliaries,  in  combination  with  the  already  established  simple  anchorage. 

Re-enforced  anchorage  is  not  a  definite  form  of  anchorage,  but  the 
term  is  used  and  defined  because  of  the  need  of  a  general  term  including 
all  of  the  combinations  of  resistance  units  tending  to  seciure  stationary 
anchorage.  The  defined  forms  of  anchorage  known  as  intermaxillary 
and  occipital  anchorage  may  also  be  designated  as  re-enforced  anchor- 
age when  they  are  used  as  auxiliaries. 


684 


ORTHODONTIA. 


It  is  evident  that  in  the  eflfort  to  obtain  a  stationary  anchorage,  the 
established  simple  anchorage  must  be  re-enforced  in  the  principal  direc- 
tions in  which  delivered  force  is  to  be  antagonized,  viz.,  bucco-lingually 
and  antero-posteriorly. 

Bucco-lingual  Re-enforcement  of  Anchorage. — The  primary  molar 
anchorage  used  with  the  expansion  arch  may  be  re-enforced  bucco-lin- 
gually by  the  use  of  multiple  bands,  by  properly  formed  and  arranged 
buccal  tubes,  by  ligatures  or  lingual  wire 
extensions  to  molar  anchor  bands,  and  by 
intermaxillary  force. 

Multiple  Band  Re-enforcements. — ^The 
uniting  of  two  bands  on  adjoining  teeth,  at 
L  in  Fig,  546,  will  re-enforce  the  molar 
anchorage  not  only  bucco-lingually,  but 
mesio-distally  as  well.     The  resistance  of 


£ 


(^^a 


Fig.  546. 


Fig.  547. 


several  teeth  may  be  secured  by  the  use  of  the  lingual  wire  extension 
as  at  M  or  by  uniting  two  bands  with  a  lingual  wire  as  at  N  in  the 
same  illustration.     (Fig.  546.) 

Form  and  Arrangement  of  Buccal  Tubes  for  Re-enforcement  of  Anchor- 
age.— Buccal  tubes  may  be  round,  oval,  or  square,  arranged  horizontally 
or  vertically,  according  to  the  needs  of  anchorage.  In  simple  cases  in 
which  the  molar  anchor  tooth  is  not  to  be  moved  bodily,  and  there  is  to 
be  no  bucco-ling\ial  force  exerted  upon  it,  the  round  horizontal  buccal 
tube  answers  the  purpose.  In  case,  however,  the  molar  anchor  tooth 
is  to  be  moved  bodily,  or  resist  bucco-lingual  displacement,  the  oval  or 
modified  square  buccal  tubes  should  be  used  with  an  expansion  arch 
having  similarly  shaped  ends  fitting  closely  in  the  tubes.  Some  of  the 
modifications  of  horizontal  buccal  tubes  specially  made  to  prevent 
bucco-lingual  displacement,  or  for  the  bodily  movement  of  the  anchor 
teeth,  are  shown  in  Fig.  547. 


DYNAMICS   AND    ANCHORAGE.  685 

A  represents  an  oval  tube;  B,  a  sliding  lock  arrangement  (Hawley) ; 
C,  a  sliding  lock  device  (Ottolengui) ;  D,  the  square  tube  (Kemple); 
E,  F,  and  G,  varying  methods  in  use  with  the  horizontal  buccal  tubes 
(Barnes). 

The  vertically  arranged  buccal  tubes  are  used  principally  with  thread- 
less  expansion  arches,  and  are  adapted  for  resisting  bucco-lingual  dis- 
placement or  for  the  bodily  movement  of  the  anchor  teeth.  Fig.  548  shows 
the  round  vertical  tube  of  Ainsworth  and  lock  of  Barnes,  this  round  form 
of  tube  allowing  a  rotary  tendency  of  the  anchor  tooth,  however. 

An  oval  tube,  in  place  of  the  round  one,  will  overcome  the  rotary 
tendency  of  the  molar  anchor  tooth  and  effectually  resist  bucco-lingual 
displacement  as  well. 


■=vsj 


Fig.  548.  Fig.  549. 

Whichever  form  of  tube,  horizontal  or  vertical,  is  used,  it  should  be 
located  as  near  the  gingival  edge  of  the  band  as  possible  to  be  nearest 
the  center  of  greatest  resistance  in  the  root  portion  of  the  anchor  tooth. 

Ligatures  and  Lingual  Wires  for  Anchorage  Re-enforcement. — 
The  primary  molar  anchorage  may  be  further  re-enforced  bucco-lingu- 
ally  by  lingual  wh-e  extensions  from  the  anchor  bands,  or  by  ligatures 
attached  to  plain  bands  upon  the  bicuspids. 

Fig.  549  illustrates  the  re-enforcement  of  the  molar  anchorage  bucco- 
ingually  by  the  ligating  of  the  bicuspids  de  on  both  sides  of  the  dental 
arch.  In  the  use  of  ligatures  on  bicuspids  it  is  absolutely  necessary  to 
band  these  teeth  and  solder  on  retaining  spurs  to  prevent  the  ligatures 
from  slipping  beneath  the  gums  and  injuring  the  peridental  membrane. 
The  only  alternative  possible  is  the  use  of  a  sturrup  wire  ligature  sug- 
gested by  Lourie,  as  shown  at  D  in  Fig.  587.  Much  of  the  time 
spent  in  making  bands  for  bicuspids  is  saved  by  the  use  of  the  lingual 
wire  extensions  as  shown  in  Fig.  550,  an  arrangement  for  use  in  the 
deciduous  dental  arch,  but  serving  equally  as  well  in  the  permanent 
dental  arch  (Hawley). 


686 


ORTHODONTIA. 


A  design  of  the  author's  for  a  clamp  band  with  the  lingual  wire 
simply  an  extension  of  the  lingual  screw  is  shown  in  Fig.  551 

The  lingual  wire  extensions  may  be  also  used  to  even  better  advan- 
tage with  the  plain  anchor  band  since  it  can  be  made  to  extend  from  the 
cuspid  to  the  second,  or  on  occasion  the  third,  molar  as  in  Fig.  552,  thus 
securing  a  very^  greatly  increased  resistance  to  bucco-lingual  dis- 
placement. 


Fig.  550.     {Hawley.) 

Occasionally  the  lingual  wire  extensions  may  be  soldered  to  a  cus- 
pid or  bicuspid  band  on  the  same  side  of  the  arch  as  the  anchor  band,  or 
an  entire  lingual  arch  wire  extending  from  one  anchor  band  to  the  oppo- 
site side  may  be  used  for  re-enforcement  of  anchorage  bucco-lingually. 

Intermaxillary  anchorage  may  also  be  used  as  a  re-enforcement  of  a 
simple  anchorage  bucco-lingually  as  shown  in  Fig.  553. 

Here  the  intermaxillary  force  is  re-enforcing  the  lower  molar 
anchorage,  by  operating  to  assist  the  force  of  the  expansion  arch 
in  moving  the  upper  molar  from  lingual  to  normal  occlusion. 


Fig.  551. 


Fig.  552 


Antero-posterior  Re-enforcement  of  Anchorage. — ^The  primary 
simple  anchorage  may  be  re-enforced  antero-posteriorly  by  some  of  the 
same  arrangements  as  in  bucco-lingual  re-enforcement,  such  as  the  hori- 
zontal and  vertical  oval,  or  square  buccal  tubes,  the  lingual  wire  exten- 
sions soldered  to  bicuspid  bands  or  the  use  of  the  entire  lingual  arch  wire 
attached  to  the  anchor  bands. 

Intermaxillary  Anchorage  Re-enforcement  Antero-posteriorly. — It  is 
frequently  necessary  to  re-enforce  a  simple  anchorage  antero-posteriorly 


DYNAMICS   AND   ANCHORAGE. 


687 


by  the  use  of  intermaxillary  anchorage,  in  which  case  the  intermaxillary 
force  is  applied  as  in  Fig.  555. 

Occipital  Anchorage  Re-enforcement  Antero-posteriorly. — For  the 
same  reason  that  intermaxillary  anchorage  is  often 
used  for  re-enforcement  of  already  established 
anchorage,  occipital  anchorage  is  occasionally 
used  as  an  auxiliary  re-enforcement  to  the  simple 
anchorage,  and  to  intermaxillary  anchorage,  es- 
pecially in  the  treatment  of  cases  of  Class  II, 
Div.  I,  in  which  the  intermaxillary  force  or  an- 
chorage is  insufficient  to  produce  the  desired 
results. 

In  Fig.  554  is  illustrated  the  combined  use  of 
occipital  and  intermaxillary  anchorage  in  connec- 
tion with  the  estabhshed  simple  anchorage  for 
the  treatment  of  stubborn  or  advanced  cases  of 
Class  II,  Div.  I. 

Intermaxillary  anchorage  may  be  defined  as  the  opposing  of 
the  resistance  of  the  teeth  in  one  arch  against  the  resistance  of  the  teeth 


Fig.  553. 


Fig.  554. 

of  the  other  arch,  partially  or  completely,  to  the  advantage  of  tooth  move- 
ment in  the  arch  in  which  the  lesser  resistance  is  established. 


688 


ORTHODONTIA. 


In  reality  this  form  of  anchorage  is  the  anchoring  of  intermaxillary 
force  for  its  effective  use  in  elevation  of  teeth,  the  re-enforcement  of  a 
simple  or  stationary  anchorage,  or  for  shifting  the  occlusion. 

This  valuable  form  of  anchorage  is  applicable  to  all  classes  of  mal- 
occlusion and  its  use  is  indispensable  in  modern  orthodontic  treatment. 

Its  use  in  tooth  elevation  is  shown  in  a  complex  case  of  infra-occlu- 
sion in  Fig.  650. 


Fig.  555. 

fn  Fig.^555  its  use  is  illustrated  in  a  Class  I  case  in  re-enforcing  a 
simple  anchorage  in  the  lower  arch  by  adding  the  resistance  of  the  entire 
upper  arch  CD  through  the  medium  of  the  intermaxillary  force  F;  at 
HF  is  exhibited  a  similar  re-enforcement  of  the  upper  molar  anchorage 
H  of  a  Class  I  case  by  adding  the  resistance  of  the  lower  arch  EG. 


Fig.  556. 


Fig.  557. 


In  Class  II  the  use  of  intermaxillary  anchorage  is  primarily  intended 
for  shifting  of  the  occlusion  as  in  their  arrangement  in  Fig.  556,  but  in 
cases  complicated  by  deep  underbite,  the  attachment  of  the  intermax- 
illary elastics  is  arranged  as  in  Fig.  557  so  that  the  force  may  operate 
in  two  different  directions,  ED  and  KD,  elevating  the  molars  and  shift- 
ing the  occlusion  at  the  same  time. 


DYNAMICS   AND   ANCHORAGE.  689 

Uses  of  Intermaxillary  Anchorage. — Briefly  stated,  the  various 
methods  of  application  of  intermaxillary  anchorage  are  as  follows: 

The  use  of  either  arch  of  teeth,  en  phalanx,  as  anchorage  for  the 
attachment  of  the  rubber  ligature  to  effect  the  movement  of  one  or 
more  teeth  in  the  opposite  arch. 

The  upper  arch  used  (en  phalanx)  as  resistance  for  the  consecu- 
tive mesial  movement  of  the  lower  incisors,  cuspids,  bicuspids,  and 
molars. 

The  lower  arch  used  (en  phalanx)  as  resistance  for  the  consecu- 
tive mesial  movement  of  the  upper  incisors,  cuspids,  bicuspids  and 
molars. 

The  use  of  either  arch  of  teeth  in  whole  or  part  as  anchorage  for  a 
simultaneous  mesial  movement  of  teeth  in  one  arch  and  a  distal  move- 
ment of  teeth  in  the  other  arch. 

The  use  of  the  intermaxillary  anchorage  to  sustain,  or  as  an  auxiliary 
to,  other  established  anchorage. 

The  elevation  of  teeth  in  either  arch. 

The  use  of  intermaxillary  anchorage  between  single  teeth  of  oppo- 
site arches,  in  opposing  their  resistance  to  mutual  advantage  in  mesial 
or  distal,  and  buccal  or  lingual  movement. 

The  reciprocation  of  the  movement  of  teeth  in  the  use  of  inter- 
maxillary anchorage,  is  not  claimed,  although  it  may  and  does  occur 
under  proper  conditions,  as  when  the  anchorage  resistance  in  one  arch 
exactly  balances  that  of  the  other. 

Intermaxillary  force  is  always  reciprocal ;  intermaxillary  anchorage 
may  be  reciprocal  or  not,  i.e.,  the  resistance  in  one  arch  may  be  equal 
to  that  of  the  other,  or  it  may  be  greater  or  less. 

Occipital  Anchorage  is  the  use  of  the  top  and  hack  of  the  head  in 
connection  with  the  headgear  as  anchorage  in  cases  in  which  a  powerful 
extraneous  force  is  needed  for  antero-posterior  tooth  movements. 

This  valuable  form  of  anchorage  has  dropped  somewhat  into  disuse, 
because  of  the  splendid  results  which  are  now  obtainable  by  the  use  of 
the  intermaxillary  anchorage. 

The  chief  use  of  this  method  of  anchorage  is  in  connection  with  the 
treatment  of  Class  II  and  III  cases,  in  which  the  anchorage  within  the 
mouth  is  not  suflQcient  to  meet  the  requirements  of  the  case. 

Fig.  558  shows  the  Angle  headgear  and  traction  bar  in  position  for 
the  application  of  occipital  anchorage,  the  socket  of  the  traction  bar 
engaging  with  the  ball  soldered  on  the  front  of  the  expansion  arch. 

Occipital  anchorage  is  seldom  indicated  except  in  unusually  re- 
fractory cases  of  Class  II  or  III,  in  which  it  is  an  efficient  auxiliary. 
44 


690 


ORTHODONTIA. 


Reciprocal  anchorage  represents  the  counterbalancing  of  anchorage 
resistance  between  teeth  located  in  different  parts  of  the  same  arch,  or  in 
opposite  arches,  to  the  rnutual  advantage  of  the  various  tooth  movements. 

In  expansion  of  the  dental  arch  as  in  Fig.  549  a,  the  molar  anchorage 
c  is  equally  antagonizing  the  opposite  anchorage  b,  the  lateral  forces 
f  and  a  being  equally  free  to  operate  because  of  their  similar  attach- 
ments in  round  buccal  tubes.  If  a  bicuspid  on  each  side  be  ligated 
to  the  expansion  arch,  there  is  also  reciprocal  re-enforcement  of  an- 
chorage at  d  and  e. 

Again  in  the  use  of  intermaxillary  anchorage  there  is  a  reciprocation 
of  anchorage  between  the  opposing  dental  arches  as  in  Fig.  555  in 


iiL,.    550. 


which  the  reciprocation  of  force  and  anchorage  is  suflQcient  to  sustain 
the  established  anchorage  of  the  upper  first  molar  to  distal  movement. 
Reciprocation  of  Anchorage  of  Expansion  Arch  and  Traction 
Screw. — Without  considering  in  this  connection  the  advisabiHty  of  the 
extraction  of  the  first  bicuspid,  and  retraction  of  the  cuspid  into  its  space 
in  a  case  of  Class  II,  Div.  11,  Subdivision,  it  may  be  well  to  illustrate, 
in  Fig.  559,  a  form  of  anchorage  devised  by  Angle,  the  application  of 
the  traction  screw  and  expansion  arch  in  efl&cient  combination  for  the 
successful  attainment  of  the  result  desired  of  harmonizing  the  size  of 
the  arches  without  shifting  the  occlusion  in  the  molar  region,  an  opera- 
tion which   is  unnecessary   from   the  standpoint  of  perfect  occlusal 


DYNAMICS   AND    ANCHORAGE. 


691 


restoration,  yet  is  here  illustrated  for  the  purpose  of  exhibiting  the 
reciprocation  of  force  from  one  appliance  to  the  other  in  the  attainment 
of  the  result. 

It  will  be  observed  that  the  long  sheath  of  the  traction  screw  is 
attached  directly  to  the  molar  clamp  band,  and  the  short  tube  on  the 
cuspid  band,  which  engages  the  right  angled  end  of  the  traction  screw, 
is  attached  at  one  corner  only,  at  right  angles  to  the  direction  of  the 
desired  movement. 

The  expansion  arch  is  supported  by  a  short  tube  soldered  to  the 
under  side  of  the  forward  end  of  the  sheath  of  the  traction  screw  on 
this  side,  the  other  end  being  supported  by  the  usual  tube  on  the  molar 
clamp  band. 


Fig.  559.     {Mter  Angle.) 


The  reciprocating  of  the  force  acting  to  rotate  the  incisors  through 
the  forward  movement  of  the  expansion  arch,  and  antagonizing  the 
distal  force  of  the  traction  screw  in  drawing  the  cuspid  backward,  is 
the  feature  of  especial  value. 

Reciprocating  Expansion  Arches. — One  of  the  most  ingenious 
examples  of  a  reciprocal  and  a  re-enforced  anchorage  is  embodied  in 
the  principle  of  an  appliance  shown  in  Fig,  543,  devised  by  C.  S.  Case. 

It  consists  of  two  buccal  arches,  supported  by  tubes  soldered  to 
each  other  at  slightly  diverging  angles,  the  inner  one  united  to  a  molar 
band  and  supporting  a  threaded  arch  of  about  19  gauge,  which  is 
attached  to  the  incisal  ends  of  vertical  bands  upon  the  incisor  teeth, 
the  outer  tube  supporting  an  ordinary  expansion  arch,  which  is  some- 
what flattened  as  it  engages  with  hooks  at  the  gingival  end  of  the  same 
vertical  bars  upon  the  incisor  bands. 

Turning  up  the  nuts  in  front  of  the  tube  supporting  the  upper  arch 


692  ORTHODONTIA, 

the  roots  of  the  incisors  are  pushed  forward  and  the  crowns  inhibited 
in  movement  or  retruded  slightly  as  desired  by  control  of  the  nuts 
behind  the  anchor  tubes  supporting  the  lower  arch.  The  resulting 
effect  of  these  opposite  acting  forces  is  to  produce  an  equilibrium  of 
forces  in  the  region  of  the  molar  anchorage,  and  this  unique  application 
of  the  arches  can  be  classed  under  reciprocal  anchorage  when  the  force 
and  resistance  are  equally  balanced. 

Mechanical  Advantage.— The  dynamical  features  presenting  in 
the  correction  of  malocclusion,  require  that  only  that  appliance  should 
be  used  which  shall  possess  the  greatest  mechanical  advantage  in  its 
application,  and  consequently,  conserve  all  of  the  energy  possible, 
both  of  force  and  resistance. 

In  the  conformation  of  appliances  to  the  principle  of  the  conser- 
vation of  energy,  we  must  recognize  the  primary  axiom,  "the  work 
done  by  the  effort  must  equal  the  work  done  in  overcoming  the  resist- 
ance," and  that  the  test  of  the  efficiency  of  any  appliance  is  the  nearest 
approach  to  the  securing  of  resistance  and  application  of  force  which 
shall  be  the  most  useful  and  the  least  wasteful  of  the  energy  which  is 
being  used. 

**  If  a  machine  could  be  made  which  wasted  no  energy,  the  resist- 
ance being  all  useful,  and  not  wasteful,  the  machine  would  be  perfect, 
and  its  efficiency  would  be  unity." 

Theoretically,  we  can  imagine  an  appliance  for  moving  teeth,  having 
every  mechanical  advantage,  sufficient  resistance  in  anchor  teeth, 
sufl5cient  and  controllable  potential,  and  direct  application  of  its  force, 
with  no  loss  of  energy  at  any  point,  but  in  practice  we  are  confronted 
with  such  obstacles  as  friction,  insufficient  and  unstable  resistance,  in- 
direct application  of  force,  etc. 

Efficiency  of  Appliances. — The  efficiency  of  any  appliance,  there- 
fore, can  be  expressed  in  a  proper  fraction,  or  a  percentage  of  the  total 
amount  of  energy  put  into  it.  Simplicity  in  construction  and  operation 
is  a  prime  factor  in  the  determination  of  the  efl&ciency  of  an  appliance, 
since  the  least  number  of  working  parts  reduces  the  amount  of  friction 
and  other  wasteful  energy. 

The  stability  or  fixation  of  the  basal  attachments  of  appliances, 
the  material  of  which  they  are  constructed,  the  size  and  temper  of 
wires  and  ligatures,  and  the  amount  of  power  capable  of  being  pro- 
duced, are  likewise  essential  factors  in  the  efficiency  of  any  force 
producing  mechanism  used  in  orthodontia. 

It  is  obvious  that  an  appliance  should  not  only  have  the  most 
stable  attachments,  sufficient  resistance  to  the  applied  force,  which  is 


DYNAMICS  AND  ANCHORAGE.  693 

most  direct  in  its  application,  but  also  that  the  force  itself  should  be 
great  enough  and  under  such  control  that  the  time  rate,  or  power  of 
accomplishment  of  certain  desired  tooth  movements  maybe  somewhat 
accurately  gauged. 

The  efficiency,  then,  of  an  appliance  for  the  correction  of  maloc- 
clusion consists  of  the  fewness  and  proper  proportion  of  adaptable 
parts,  capable  of  appropriating  sufl&cient  and  varied  forms  of  anchorage, 
and  having  within  its  compass  the  positive  control  of  all  of  the  teeth  of 
one  dental  arch,  conserving  time  and  energy  through  the  proper  adjust- 
ment of  each  part  so  as  to  secure  a  perfect  working  mechanism, 
and  capable  of  transmitting  force  as  rapidly  and  in  such  quantity 
as  is  consistent  with  physiological  maintenance  in  operations  on 
vital  structures. 

Conservation  of  Anchorage. — ^The  efficiency  of  an  appliance 
will  depend  finally  upon  the  skillful  manipulation  of  the  appliance 
so  that  the  least  resistance  will  always  be  offered  to  the  applied  force, 
thus  conserving  the  anchorage;  e.g.,  in  the  restoration  of  inlocked 
laterals  to  occlusion,  a  proper  conservation  of  anchorage  would  require 
that  the  space  for  the  laterals  in  the  arch  be  first  obtained  before 
attempting  their  movement  into  alignment. 

Anchorage  with  Fixed  Appliances. — ^In  the  use  of  "fixed" 
appliances  for  the  correction  of  malocclusion,  an  expansion  arch, 
supported  by  clamp  bands,  upon  molar  or  bicuspid  teeth  forms  the 
usual  basal  attachment  in  each  arch  of  teeth  for  the  obtaining  of 
sufficient  resistance  for  the  tooth  movements  in  that  arch. 

In  the  lateral  expansion  of  the  dental  arch,  the  primary  anchorage 
of  the  first  molars,  although  a  movable  anchorage,  nevertheless  may 
be  designated  as  simple  anchorage  according  to  the  definition.  The 
presence  of  the  second  molars  would  re-enforce  the  primary  anchorage,, 
although  in  severe  cases,  other  re-enforcement  of  the  primary  an- 
chorage, such  as  the  use  of  intermaxillary  anchorage,  is  necessary. 

A  combination  of  several  of  the  various  forms  of  anchorage  which 
may  be  secured  with  the  expansion  arch  in  the  same  dental  arch  is 
exhibited  in  Fig.  560. 

Simple  anchorage  would  be  here  represented  by  the  first  molars 
in  their  opposition  to  the  central  or  lateral  incisors  DEor  FG  which 
are  ligated  to  the  expansion  arch,  the  resistance  of  the  incisors  tO' 
forward  movement  being  less  than  the  molars  to  distal  movement 
when  the  nuts  HH  are  tightened.  Reciprocal  anchorage  is  maintained 
between  the  bicuspids  through  their  ligation  to  the  expansion  arch. 
The  resistance  of  one  bicuspid   B  to  buccal  movement  is  offset  or 


694  ORTHODONTIA. 

counterbalanced  by  the  ligation  of  its  mate  C  on  the  opposite  side, 
neither  affecting  to  any  degree  the  primary  first  molar  anchorage, 
since  their  lines  of  resistance  are  at  right  angles  to  the  established 
lines  of  resistance  of  the  molar  anchorage.  The  ligation  of  the  bicus- 
pids B  and  C  may  also  be  designated  as  re-enforced  anchorage,  since 
added  resistance  to  the  buccal  movement  of  the  molars  is  thus  obtained. 

The  reciprocation  of  force  between  the  spring  of  the  arch  and  the 
elasticity  of  the  rubber  wedge  between  the  left  lateral  which  is  ligated 
to  the  expansion  arch  at  G,  may  also  be  designated  as  reciprocation  of 
anchorage,  although  it  is  a  secondary  anchorage. 

Stationary  anchorage  might  be  accurately  represented  in  the  first 
molar  anchorage  when  but  one  or  two  incisors  are  ligated  to  the  ex- 
pansion arch  at  a  time. 


Fig.  560. 

Ligatures  as  Auxiliaries  in  Anchorage. — It  will  be  seen  that  in 
the  use  of  the  expansion  arch,  the  control  of  all  the  units  of  resistance 
of  individual  teeth  within  the  arch  is  obtained,  and  usually  by  the  simple 
attachment  of  ligatures  around  the  teeth  and  over  the  arch. 

Often  the  arch  is  ligated  to  the  incisors  firmly,  simply  as  a  re-enforced 
anchorage,  or  support  for  the  arch,  during  the  movement  of  cuspids  or 
bicuspids  to  alignment. 

It  is  necessary  in  many  cases,  to  secure  the  resistance  of  the  arch 
as  a  whole,  to  oppose  tooth  movement  in  the  opposite  arch,  when  the 
resistance  of  every  tooth  in  the  arch  may  be  obtained  by  proper 
ligation. 

This  being  determined,  the  application  of  the  force  from  the  expan- 
sion arch  is  obtained  by  the  firmest  attachment  of  the  ligature  to  the 
tooth  to  be  moved. 

If  there  should  be  any  possibility  of  slipping  of  ligatures,  or  if  rota- 


DYNAMICS  AND  ANCHORAGE.  695 

tion  is  necessary,  the  use  of  the  Magill  band,  with  lugs,  is  a  necessity, 
as  a  continued  slipping  o£f  of  ligatures  will  delay  the  completion  of  a 
case  for  months. 

The  use  of  intermaxillary  anchorage  is  called  for  in  all  classes  of 
malocclusion,  either  for  the  direct  application  of  intermaxillary  force 
or  for  purposes  of  auxiliary  anchorage  resistance,  and  will  be  further 
described  under  treatment. 

Summary  of  Anchorage  Principles. — In  summing  up  our  re- 
marks on  the  subject  of  anchorage,  we  are  led  to  the  following  con- 
clusions: 

First,  that  the  primary  principles  of  force  and  resistance  in  action 
and  reaction  apply  equally  well  in  the  attachment  of  the  appliances 
in  orthodontia  as  in  other  fields  of  applied  mechanics. 

Second,  the  subject  of  anchorage  resolves  itself  into  that  of  compara- 
tive measures  of  resistance,  always,  however,  with  the  securing  of  a 
greater  resistance  at  the  base  of  attachment  of  an  appliance  than  that 
to  be  overcome  at  the  point  of  delivery  of  the  force. 

Third,  that  the  applied  force  shall  be  sufficient  for  the  required 
tooth  movements,  and  under  perfect  control. 

Fourth,  that  the  force  be  applied  in  the  most  direct  manner  for  tooth 
movement,  but  not  so  rapidly  as  to  endanger  its  own  basal  anchorage 
attachments,  or  cause  undue  strain  on  the  teeth  and  consequent  pain. 

Fifth,  that  the  force  producing  appliance  be  simple  and  yet  correct 
in  principle  for  the  restoration  of  normal  occlusion. 

Sixth,  that  the  addition  of  re-enforced  anchorage  of  any  kind  is 
advisable  where  the  primary  anchorage  is  not  sufficient  for  the  desired 
tooth  movements. 

Seventh,  that  advantage  should  be  taken  of  reciprocal  anchorage 
whenever  possible,  either  in  the  same  arch,  or  opposing  arches,  for 
sustaining  the  stability  and  integrity  of  the  primary  anchorage,  as  well 
as  increasing  the  efficiency  of  the  appliance. 

Eighth,  that  the  principle  of  fixation  be  observed  in  the  stability  of 
anchorage  attachments  and  the  direction  and  control  of  forces  therefrom. 

Ninth,  in  the  use  of  intermaxillary  anchorage,  especially  in  con- 
nection with  the  primary  established  anchorage  in  both  arches,  the 
greatest  attainment  in  the  scientific  application  of  anchorage  is  achieved, 
and  the  most  difficult  results  obtained  in  the  treatment  of  malocclusion. 

Tenth,  that  the  appliances  must  be  kept  up  to  their  highest  standard 
of  efficiency  at  all  times  during  the  progress  of  treatment  in  order  to 
conserve  anchorage  and  the  length  of  time  for  operation. 


696  ORTHODONTIA. 

PART    VI. 
OPERATIVE  TECHNIC. 

Application  of  Principles. — In  practical  operative  technic,  whether 
it  be  in  the  use  of  an  expansion  arch  or  an  appliance  of  different  principle 
and  construction,  its  application  to  the  teeth  in  securing  correct  forms 
of  anchorage  and  in  the  direction  and  control  of  force,  will  be  gov- 
erned by  the  same  principles  of  dynamics  and  anchorage  elaborated 
upon  in  Part  V. 

The  Expansion  Arch. — Simplicity  in  appliance  construction  and 
efficiency  in  operation  has  evolved  the  modern  expansion  arch,  which, 
examined  very  carefully  with  its  anchor  bands  will  be  found  to  possess 
certain  characteristics  which  stamp  it  as  the  most  superior  of  all 
appliances  for  the  complex  requirements  in  orthodontia.  Chief 
among  these  qualites  are  its  universality  of  application  and  efficiency  of 
mechanism. 

Its  principal  mechanical  features  are  its  possession  of  the  principles 
of  the  spring,  the  screw,  and  the  lever,  the  center  of  the  spring  being 


Fig.  561. 

m  the  center  of  the  bow  of  the  arch,  which,  from  end  to  end,  presents 
the  appearance  of  a  double  jackscrew,  with  all  the  advantages  of  the 
fine  gradations,  yet  strong  and  efficient  force  of  the  screw  principle. 

When  anchored  in  position  upon  molar  bands  upon  the  teeth,  it  can 
be  used  as  a  reciprocating  spring  for  the  balancing  of  force  and  resist- 
ance from  one  side  of  the  arch  to  the  other,  for  lateral  and  anterior 
expansion  and  all  of  the  movements  of  teeth  within  its  compass,  and 
as  a  base  of  anchorage  for  tooth  movement  in  the  opposite  arch. 

The  expansion  arch  should  be  possessed  of  a  very  hard  temper,  so 
as  to  be  capable  of  the  greatest  possible  amount  of  spring  for  expansion 


OPERATIVE    TECHNIC.  697 

purposes,  and  should  be  furnished  in  lengths  according  to  the  size  of 
the  dental  arch,  and  degrees  of  resistance  to  be  encountered. 

Variety  in  Form  of  the  Expansion  Arch. — Since  the  first  edition 
of  this  chapter  in  1908  in  which  the  author  described  three  different 
sizes  of  an  expansion  arch  but  of  similar  form  as  the  one  shown  in 
Fig.  561,  there  have  been  introduced  a  number  of  valuable  modifications 
in  its  size  and  form,  adopted  because  of  certain  well-defined  needs, 
such  as  variation  in  size  from  16  to  21  gauge,  its  division  into  sections, 
milling  of  the  ends  to  fit  oval  or  square  buccal  tubes,  and  its  construc- 
tion with  and  without  threaded  extremities.  The  change  from  a  wire 
of  large  gauge  to  one  of  a  smaller  diameter  is  a  factor  in  efficiency  which 
is  well  worth  consideration.  As  stated  in  the  previous  chapter,  the 
expansion  arches  of  smaller  gauge  are  more  capable  of  imparting  their 
elasticity  in  the  use  of  ligatures  and  the  pin  and  tube  attachments  than 
are  the  stiff er  expansion  arches  of  16  or  17  gauge.     However,  the  gain  in 


a««g 


ri-mffli 


Fig.  562. 

efficiency  in  tooth  movement  in  the  anterior  portion  of  the  dental  arch 
in  the  adult  mouth,  is  compensated  for  by  a  loss  of  efficiency  in  expand- 
ing laterally  in  the  molar  region  with  the  smaller  gauges  of  expansion 
arches,  in  which  latter  case  there  is  not  always  sufficient  lateral  spring 
to  overcome  the  resistance  in  the  molar  region.  There  is  still  a  field 
of  usefulness  for  the  larger  gauge  arches,  ranging  from  the  youthful 
cases  in  which  considerable  expansion  in  the  molar  region  is  necessary 
to  the  adult  cases,  in  which  the  larger  gauge  expansion  arches  are 
advantageous  for  lateral  expansion. 

When  expansion  arches  are  made  smaller  than  17  gauge,  they 
frequently  break  in  the  threaded  portion.  This  has  been  overcome  by 
the  use  of  an  expansion  arch  of  a  larger  standard  size,  16  gauge,  in  the 
threaded  extremities,  having  a  central  arc  of  any  desirable  narrower 
gauge,  from  16  to  20  B.   &  S.,  Fig.  562. 

The  ends  of  the  arch  are  also  milled  flat  on  two  sides  so'  that  a 
stationary  anchorage  may  be  obtained  with  the  use  of  an  oval  buccal 


698  ORTHODONTIA. 

tube.  This  style*  of  arch  has  a  further  distinct  advantage  in  the 
standardized  gauge  of  the  threaded  extremities,  in  that  at  any  time 
during  treatment,  a  change  in  the  size  of  the  arch  may  be  made  without 
changing  the  supporting  buccal  tubes  on  molar  bands. 

Threadless  Expansion  Arches. — In  the  construction  of  the  expan- 
sion arch  without  threaded  extremities,  there  have  been  three  principal 
methods  introduced,  one  in  which  the  arch  is  divided  into  three  sections, 
the  Angle  sectional  arch  composed  of  a  middle  or  threadless  section 
having  squared  ends  which  fit  into  square  sockets  of  threaded  end  sec- 
tions, A,  Fig.  563,  another  in  which  the  screw  power  is  transferred  to 
an  external  threaded  socket  fitting  in  the  buccal  tube,  the  arch  wire 
being  entirely  unthreaded,  as  in  the  Barnes'  expansion  arch  and  tube, 
Fig.  563,  B,  the  third  having  no  controlling  screw  power,  but  depend- 


\ru 


Fig.  563. 

ing  for  control  on  the  elongation  of  loops  in  a  small  gauged  base  wire  as 
in  the  attachment  BC,  Fig.  563,  devised  by  Ainsworth. 

The  Divided  Expansion  Arch. — In  order  to  secure  increased 
power  of  expansion,  particularly  in  the  cuspid  and  bicuspid  region, 
where  the  plain  expansion  arch  is  very  slow  in  action,  the  author  has 
been  using  the  divided  expansion  arch  illustrated  in  Fig.  564.  Especially 
in  extreme  cases  of  expansion  in  the  adult  mouth  the  divided  expansion 
arch  has  a  decided  advantage  over  the  plain  arch. 

The  principle  is  entirely  new,  in  its  application  to  the  outside 
of  the  dental  arch,  for  the  purpose  of  anterior  expansion.  The 
author  is  indebted  to  Bethel  for  suggesting  the  curved  tube  fitting  the 
curve  of  the  arch  instead  of  the  straight  one  previously  use.  The 
other  improvements,  such  as  the  use  of  a  D-shaped  tube  receiving  D- 
shaped  ends  of  the  two  lateral  halves  of  the  arch  so  as  to  prevent  turning 
of  the  divided  arch  in  the  tube,  are  original  with  the  author. 

This  arch  has  the  power  of  four  jackscrews  and  at  the  same  time 

♦Manufactured  by  Aderer,  New  York,  N.  Y. 


OPERATIVE    TECHNIC. 


699 


retains  the  elasticity  and  power  of  the  reciprocal  spring  as  exhibited  in 
the  plain  arch.  It  also  can  be  made  to  exert  force  in  the  directions 
indicated  by  the  arrows  in  the  illustration,  Fig.  565. 

The  divided  ends  of  the  arch  fit  snugly  into  the  central  tube,  so 


Fig.  564. 

that  the  lateral  spring  of  the  two  halves  is  as  great  as  in  the  undivided 
arch.  It  is  adjusted  the  same  as  the  plain  arch,  and  can  be  used  in 
Class  II  or  III,  where  considerable  expansion  and  a  mesial  or  distal 
change  in  the  occlusion  is  needed  at  the  same  time. 


Fig.  565. 


Adaptation  of  the  Plain  Threaded  Arch. — The  threaded  expan- 
sion arch  should  be  made  to  conform  to  the  general  outline  of  the  labial 
and  buccal  surfaces  of  the  teeth  at  the  beginning  of  treatment  in  order 
to  be  comfortable  for  the  patient,  and  at  the  same  time  no  portion  of 


700  ORTHODONTIA. 

the  expansion  arch  should  be  bent  too  far  away  from  the  teeth  at  any 
point  for  efl&cient  attachment  of  ligatures. 

Often  it  will  be  necessary  to  bend  the  arch  wire  around  a 
certain  tooth  which  is  so  far  in  labial  or  buccal  occlusion  that  it 
interferes  with  the  adaptation  of  the  expansion  arch  to  the  rest  of  the 
teeth  to  too  great  an  extent  for  comfort  or  practicability.  These  bends 
may  be  gradually  worked  out  as  the  case  progresses,  and  the  arch  is 
restored  to  normal  size  and  shape. 

Correction  of  Lines  of  Exerted  Force  in  Expansion  Arch. — ^It 
is  evident  from  a  study  of  the  dynamics  of  the  expansion  arch  that 
certain  changes  in  its  form  are  necessary  for  the  correction  of  the  lines  of 


Fig.  566. 

force  which  it  exerts  at  its  extremities.  For  example,  in  Fig.  566, 
the  arc  AB  describes  the  path  of  the  force  exerted  by  the  expansion 
arch  as  it  would  be  if  it  were  used  in  the  form  in  which  it  comes  from  the 
manufacturer.  Applied  in  this  form,  there  is  the  extreme  of  expansion 
in  the  molar  region,  while  in  the  region  of  the  cuspids  the  amount  of 
expansion  is  almost  nil.  The  molar  anchor  teeth,  following  the  path 
of  this  curve,  must  be  rotated  from  their  distal  angles. 

It  is  evident,  that  the  force  is  incorrectly  applied  in  this  manner, 
and  renders  the  work  inefficient.  To  correct  the  direction  of  the 
force  so  as  to  expand  in  the  bicuspid  region,  the  arch  must  be  bent  in  a 
broader  anterior  curve  as  at  D,  Fig.  566,  and,  to  correct  the  direction  of 
force  upon  the  molar  tooth,  the  ends  of  the  arch  must  be  rather  sharply 
bent  inward  in  front  of  the  nut  G,  so  that  the  force  will  be  directed  more 
nearly  along  the  parallel  lines,  as  indicated  by  the  arrow  EF.  Thus,  by 
this  correction  of  deficient  original  form  there  is  a  gain  in  efficiency  in 
operation  of  the  expansion  arch. 

Bucco-lingual  Alignment  of  the  Anchor  Tubes. — If  the  anchor 
band  is  one  in  which  the  buccal  tube  is  already  soldered  to  the  band,. 


OPERATIVE   TECHNIC. 


701 


care  should  be  taken  in  adjusting  the  band  so  that  the  tubes  will  be 
aligned  parallel  to  the  buccal  cusps  of  the  molar,  or  if  a  bicuspid, 
parallel  to  the  buccal  surfaces  of  the  bicuspids,  so  that  the  expansion 
arch  may  be  easily  slipped  into  the  tubes  without  unequal  tension  at 
the  end  of  the  tube  on  either  anchor  clamp  band. 

Fig,  567  illustrates  diagrammatically  the  relationship  of  the  expan- 
sion arch  to  the  tubes  on  anchor  clamp  bands,  B  and  F  representing 


A  BG 


Fig.  567. 


the  positions  of  anchor  tubes  in  which  the  ends  of  the  expansion  arch 
will  slip  easily  and  uniformly  into  them,  and  A  and  C,  positions  in 
which  the  tubes  are  so  far  from  the  parallel  that  the  arch  cannot 
be  readily  inserted,  and  which  would  be  creative  of  unequal  ten- 
sion upon  the  molar  to  such  a  degree  that  rotation  of  this  tooth 
would  be  inevitable,  and  the  easy  manipulation  of  the  arch  interfered 
with. 

Where  it  is  desired  to  rotate  the  molar  on  which  the  anchor  clamp 
band  is  placed,  the  end  of  the  expansion  arch  may  be  bent  lingually 
from  a  point  in  front  of  the  nut  as  in  D,  Fig.  567,  and  the  expansion 
arch  sprung  into  place,  causing  the  mesial  angle  of  the  molar  to  turn 
buccally  and  the  distal  angle  lingually,  A  buccal  bend  as  at  E  will 
cause  the  tooth  to  rotate  in  the  opposite  direction. 

Vertical  Alignment  of  Expansion  Arch. — Although  the  anchor 
tubes  may  be  aligned  so  that  they  allow  the  arch  to  be  readily  slipped 


702  ORTHODONTIA. 

into  them  as  just  described,  it  will  usually  be  found  that  the  bow  of 
the  arch  is  either  too  high  or  too  low  on  the  labial  surface  of  the  inci- 
sors, often  as  at  AED,  Fig.  568,  the  arch  resting  against  the  incisal  edges. 
To  establish  a  correct  vertical  alignment  of  the  front  of  the  arch  without 
unsoldering  the  anchor  tubes,  if  the  upward  or  downward  inclination  of 
the  arch  is  not  too  great,  the  mesial  and  distal  edges  of  the  band  may  be 
slightly  raised  or  lowered  so  that  the  arch  will  rest  against  the  labial 
surface  of  the  incisors  near  the  necks,  and  by  burnishing  the  edges 


v'/  / 

"    '      E 
L-^  ^- 


^ 


Fig.  568. 


of  the  band  tightly  in  these  positions,  and  re-tightening  the  lingual 
nut,  the  security  of  the  clamp  band  will  not  be  endangered. 

Another  method  that  is  of  advantage  in  some  cases  is  to  bend  the 
expansion  arch  in  front  of  the  nuts  at  E,  Fig.  568,  so  the  front  of  the 
arch  will  rest  in  its  proper  position,  AEF,  upon  the  labial  surfaces  of 
the  incisors. 

r\ 

(    « 

Fig.  569. 

The  author  prefers  to  unsolder  the  anchor  tubes  in  case  of  any 
great  variation  from  the  desired  alignment,  and  re-align  them  so  that 
the  arch  and  anchor  tiibes  will  be  in  the  same  plane  when  in  proper 
position,  as  at  HN  in  Fig.  569,  the  force  being  delivered 
more  directly,  and  being  less  liable  to  tip  up  the  molar 
anchor  tooth.  The  change  of  alignment  by  this  method 
^^^^~7^Q  is  very  easily  accomplished  by  the  use  of  the  soldering 
clamps  as  illustrated  in  Fig.  781  in  the  chapter  on  con- 
structive technic. 

The  form  of  anchor  clamp  band  with  the  pivotal  tube,  a  design  of 


OPERATIVE   TECHNIC.  703 

the  author's,  shown  in  Fig.  570,  is  preferred  for  some  cases,  as  it  allows 
of  a  change  of  inclination  of  the  tube  at  any  time  before  or  during 
treatment,  without  unsoldering  the  tube  or  taking  off  the  arch  or  clamp 
bands.  This  adjustable  tube  is  attached  by  a  short,  round  piece  of  wire 
to  the  clamp  band,  and  is  capable  of  being  twisted  with  the  pliers 
upward  or  downward  to  any  position  desired. 

The  saving  of  time  and  the  possibility  of  always  keeping  up  the 
standard  of  efficiency  in  the  arch  through  its  being  properly  related  to 
tooth  surfaces  is  of  great  advantage  in  the  use  of  this  anchor  clamp 
band. 

Fixation  of  the  Expansion  Arch. — In  order  to  secure  the  greatest 
efficiency  in  the  use  of  the  expansion  arch,  the  principle  of  fixation 
must  be  observed  in  every  detail  of  its  construction  and  application. 
Care  should  first  be  taken  that  the  proper  relation  between  the  expansion 
arch  and  the  buccal  tubes  exists.  For  example,  force  is  lost  and  in- 
direcdy  applied  when  the  expansion  arch  is  supported  by  a  loose- 


L   Iczzz-ZIllMiF^ 


M  |c---_-iC]lPIH 


Nic-------|-i5ti 


O  IC--ZZZh^!llHfl 
Fig.  571. 

fitting  buccal  tube,  which  allows  upward  and  downward  play  of  the 
arch.  Cases  have  been  delayed  for  many  months  and  have  failed  to  be 
successfully  treated  on  account  of  a  loose-fitting  tube  and  a  loose  nut. 
The  drawing  L  in  Fig.  571  shows  a  loose-fitting  tube  in  conjunction 
with  a  plain  nut  on  the  expansion  arch,  a  combination  which  is  always 
inefficient,  because  of  the  nut  being  easily  unturned  during  mastication, 
and  because  of  the  excessive  play  of  the  arch  in  the  buccal  tube.  The 
friction  sleeve  nut  and  loose-fitting  tube  shown  at  M,  is  a  long  step  in 
advance,  since  the  nut  is  prevented  from  unturning  by  the  friction  of  a 
tight-fitting  sleeve  on  the  buccal  tube.  There  need  not  necessarily  be 
any  play  of  the  expansion  arch  in  the  buccal  tube  when  this  style  of  nut 
is  used,  but  there  is  in  many  of  the  tubes  furnished  with  the  friction 
sleeve,  and  this  play  eventually  enlarges  the  friction  sleeve  so  that  the 


704  ORTHODONTIA. 

nut  easily  unturns,  and  the  applied  force  is  rendered  inactive.  The  play 
of  the  arch  in  the  buccal  tubes  also  tends  to  loosen  ligatures  and  to 
lessen  the  power  and  change  the  direction  of  the  force  at  the  point  of 
delivery.  The  mechanically  perfect  form  of  the  friction  sleeve  combina- 
tion would  be  embodied  in  the  additional  use  of  the  close-fitting  buccal 
tube. 

The  drawing  N  illustrates  a  close-fitting  buccal  tube  supporting 
the  expansion  arch,  and  the  double  locking  nuts  engaging  the  end  of 
the  buccal  tube.  This  combination  is  rather  complicated,  and  is  but 
little  used,  although  the  close-fitting  buccal  tube  eliminates  all  play  of 
the  arch  in  the  tubes,  and  the  use  of  the  double  nuts  tightened  against 
each  other  eliminates  all  possibilities  of  loss  of  force  at  points  of 
delivery. 

However,  the  writer  believes  that  he  has  devised  a  still  better 

combination,  in  that  it  is  simpler  and  takes  a  shorter  time  to  adjust,  the 

^^^^  close-fitting  buccal  tube  and  split 

_  ,„__/^^^^^^'  ""^     nut  shown  in  the  drawing  O.     The 

p  split  portion  of  the  nut  is  pinched 

together  before  the  nut  is  run  on  the 

expansion  arch,  so  that  it  exerts  a  continual  strong  spring  pressure  upon 

the  threads  of  the  arch  when  in  position,  thus  preventing  any  upturning 

except  when  the  wrench  is  used. 

With  this  combination  the  arch  is  steadily  supported  by  the  close- 
fitting  buccal  tube,  doing  away  with  all  upward  and  downward  play  of 
the  arch,  and  the  firmly  set  split  nut  keeps  up  the  force  exerted  against 
the  end  of  the  buccal  tube  until  the  resistance  anterior  to  the  nut  is 
overcome.  In  other  words,  the  principle  of  efficiency  has  been  carried 
out  to  as  near  perfection  as  is  possible  at  this  usually  inefficient  point. 

Again,  the  fixation  principle  may  be  still  further  observed  in  the 
relation  of  the  expansion  arch  to  the  buccal  tubes  by  the  exertion  of 
spring  force  from  the  arch  ends  upon  the  inside  walls  of  the  buccal 
tubes  as  shown  in  Fig.  572. 

A  curved  spring  is  ground  on  the  ends  of  the  expansion  arch  with 
a  small  carborundum  wheel,  taking  care  to  first  grind  off  the  threads. 
This  curved  spring  can  then  be  bent  upward  to  exert  any  desired 
degree  of  force  against  the  inside  of  the  buccal  tube  from  the  slightest 
spring  force,  just  sufficient  to  gently  hold  the  arch  from  slipping,  to  a 
force  so  strong  that  it  is  impossible  to  remove  the  arch  from  the  buccal 
tubes  with  the  fingers  alone. 

Arch  Removing  Plier. — Owing  to  the  closeness  of  the  expansion 
arch  to  the  anterior  teeth,  and  its  fixedness  in  the  buccal  tube,  it  is 


OPERATIVE    TECHNIC. 


705 


somewhat  difficult  to  grasp  and  remove  the  arch  with  the  fingers. 
The  author's  arch  removing  plier,  Fig.  573,  having  transverse  grooves 
upon  the  inside  of  the  beaks,  permits  of  a  firm  grasp  and  easy  removal  of 
the  expansion  arch. 

Forms  of  Anchor  Bands. — The  bands  supporting  the  buccal  tubes, 


~i...<^aii 


Fig.  573. 

on  anchor  teeth  are  applicable  in  two  different  forms,  the  clamp  band 
Fig.  574,  and  the  plain  band.  Fig.  575. 

The  clamp  band  with  lapping  ends  (Fig.  574)  to  cover  the  other- 
wise exposed  lingual  surfaces  of  the  anchor  tooth,  suggested  by 
Barnes,  is  preferred  to  the  style  of  band  made  without  lapping  ends. 


Fig.  575. 


Fig.  574. 


Fig.  576  illustrates  the  author's  design  for  a  clamp  band  which 

provides  a  lingual  screw  and  extension  arm  in  one  piece,  for  use  in 

cases  in  which  it  is  desirable  to  avoid  ligatures  upon  the  deciduous 

molars  or  bicuspids  anterior  to  the  anchor  teeth, 

^Another  design  (Fig.    577)    provides  an  adjustable  buccal  tube 


'Fig.  576. 


Fig.  577. 


Fig.  578. 


which,  being  added   to  an   intervening   torsion  rod,  permits  of  ad- 
justment in  the  vertical  plane  through  twisting  of  the  torsion  rod. 

Where  free  pivotal  action  is  desired  as  in  moving  molars  distally, 
the  pivotal  tube  clamp  band  (Fig.  578)  designed  by  the  author,  may  be 
used. 

45 


7o6 


ORTHODONTIA. 


Adjustment  of  Anchor  Clamp  Bands. — In  the  adjustment  of 
clamp  bands  to  molar  or  bicuspid  teeth,  it  is  often  necessary  to  avoid 
discomfort  to  the  patient  or  buckling  of  the  bands,  that  the  teeth  to  be 
banded  be  first  separated  sufficiently  to  allow  of  the  easy  slipping  of  the 
edges  of  the  bands  between  the  interproximate  contact  points  on  either 
side.  This  is  accomplished  by  tying  silk,  or  twisting  wire  ligatures 
around  the  contact  points  and  leaving  them  in  position  for  a  period  of 
at  least  twenty-four  hours. 

In  using  the  silk  ligature  for  this  purpose,  a  loop  of  No.  3  ligature 

silk  is  engaged  in  a  loop  of  fine 
waxed  floss  silk,  and  the  latter 
slipped  between  the  contact  points 
of  the  adjoining  teeth,  as  in  Fig. 
57Q,  and  drawn  through  together 
with  the  heavy  ligature  silk  as  at  A. 
The  silk  floss  is  then  removed,  and 
one  free  end  of  the  ligature  silk 
passed  through  the  loop  emerging 
from  the  interproximate  space. 
The  two  free  ends  are  next  drawn 
taut  and  tied  securely  around  the 
contact  points  as  at  C.  If  wire  is 
preferred  for  separation,  a  heavy 
ligature  wire  is  slipped  beneath  the 
contact  points,  and  the  two  free 
ends  brought  together  above  and 
twisted.  After  cutting  off  the  long 
ends  the  short  twisted  ends  should 
be  bent  into  the  embrasure  of  the 
adjoining  teeth  so  as  not  to  irritate 
the  cheeks. 

After  the  adjacent  contact  points 
of  the  tooth  to  be  banded  have 
been  separated  sufficiently,  the  circumference  of  the  clamp  band  is 
enlarged  to  fit  loosely  over  the  crown  by  unturning  the  nut  on  the 
lingual  side,  the  round  form  of  the  clamp  band  having  been  previously 
shaped  in  the  form  of  a  rounded  square.  With  the  lingual  screw  point- 
ing distally,  where  it  will  cause  the  least  discomfort  to  the  tongue,  the 
clamp  band  is  then  forced  gently  to  place  with  the  thumb,  or  with  a 
band  setting  instrument  (Fig.  580),  especially  designed  for  this  purpose 
by  the  author. 


Fig.  579. 


c 

{Items  of  Interest.) 


OPERATIVE    TECHNIC. 


707 


The  surface  coming  into  contact  with  the  edge  of  a  band  is  composed 
of  a  section  of  soft  metal  soldered  to  the  head  of  the  instrument,  which 
keeps  it  from  slipping  when  forcing  a  band  or  crown  into  place. 


Being  made  of  metal  this  instrument  can  be  easily  sterilized,  thus 
possessing  a  distinct  advantage  over  the  wooden  sticks  which  are  often 
used  for  forcing  bands  and  crowns  upon  the  teeth.  With  this  instru- 
ment the  band  may  be  pressed  uniformly  into  posi- 
tion mesially  and  distally  by  means  of  a  slight  rock- 
ing motion. 

The  edges  of  the  clamp  band  should  pass  just  be- 
neath the  gingiva  so  as  to  leave  no  surface  of  the  tooth 
exposed  to  the  possibility  of  caries  from  food  retention. 

When  in  position,  the  lingual  nut  should  be  tight- 
ened, and  the  upper  edges  of  the  band  adapted  to  the 
grooves  and  against  the  inclines  of  the  cusps  of  the  tooth,  as  shown  in 
Fig.  581.  A  band  adapter  with  a  serrated  tip  (Fig.  582)  designed  by 
J.  L.  Young,  is  a  very  efficient  instrument  for  this  purpose. 


Fig.  581. 


Fig.  582. 

Alignment  of  Buccal  Tubes. — The  buccal  tubes,  either  separate 
from,  or  already  attached  to,  the  clamp  band,  will  need  to  be  aligned 
so  that  they  lie  in  parallel  vertical  and  horizontal  planes,  allowing  the 
expansion  arch  to  rest  in  them  with  its  ends  parallel  to  each  other,  when. 


7o8  ORTHODONTIA. 

the  bow  of  the  arch  is  in  position  against  the  labial  surfaces  of  the 
incisors  near  their  gingival  borders.  The  tubes  should  also  be  at- 
tached as  suggested  by  J.  L.  Young,  so  that  the  nut  of  the  expansion 
arch  will  lie  in  the  buccal  embrasure  between  the  anchor  tooth  and  the 
tooth  mesial  to  it,  as  at  A, Fig.  583,  or  in  the  next  mesial  embrasure,  as 
at  B,  Fig.  581,  in  which  latter  case  the  buccal  tube  must  be  attached 
farther  mesially. 

The  clamp  band  should  be  finally  cemented  in  position  with  gutta- 
percha or  oxyphosphate  cement,  the  former  material  being  preferable 

when  the  operation  is  to  consume  but  a 
few  weeks'  time,  and  cement  when  the 
operation  is  of  long  duration. 

Adjustment  of  the  Plain  Anchor 
Band. — In  the  use  of  the  plain  anchor 
band  Fig.  584,  special  care  should  be  ob- 
served in  its  fitting  and  contouring  as 
upon  these  details  depend  the  efl&ciency 
of  the  plain  band  for  anchorage.  A  number  of  convenient  sizes  of 
plain  bands,  ranging  from  1.26  inches  to  1.50  inches  in  circumference, 
should  be  kept  in  stock  for  immediate  use.  The  most  used  sizes  are 
1.38  inches,  1.40  inches,  1.42  inches,  1.45  inches,  and  1.50  inches  in 
circumference,  and  they  should  be  made  of  at  least  a  34-gauge  band 
material,  in  width  about  .17  to  .23  inches. 

The  band  selected  for  the  anchor  tooth  should  fit  the  widest  portions 
of  the  crown  snugly  after  conforming  it  to  the  general  shape  of  the 
crown  and  before  any  contouring  is  done.  It  should  then  be  forced  over 
the  crown  of  the  tooth  with  the  band  setter  (Fig.  572)  until  its  gingival 
edge  passes  just  beneath  the  gums,  and  the  occlusal  edge 
should  be  adapted  to  the  buccal  and  lingual  grooves  with 
the  instrument  shown  in  Fig.  582.  The  bucco-gingival  and 
linguo-gingival  edges  of  the  band  should  next  be  contoured 
inward,  as  well  as  the  entire  occlusal  edge,  using  S.  S.  White 
contouring  pliers  No.  137,  when  the  band  is  again  pressed  into  place 
with  the  band  setter,  and  a  final  adaption  of  the  occlusal  edge  made. 
The  band  is  then  ready  for  attaching  the  buccal  tube  as  previously 
described  in  connection  with  the  clamp  band,  and  for  attaching  the 
lingual  wires  for  re-enforcement  of  anchorage.  A  method  of  H.  A. 
Baker's  for  adapting  the  plain  band  for  anchorage  is  described  on  page 
875  and  illustrated  in  Fig.  775.  The  buccal  tube  should  be  attached 
as  near  the  gingival  edge  of  the  band  as  is  practicable  in  order  to  take 


OPERATIVE    TECHNIC. 


709 


advantage  of  the  greater  resistance  of  the  anchor  tooth  at  the  neck  than 
nearer  the  occlusal  edge  of  the  tooth. 

Anchor  Band  Removing  Plier.— In  view  of  the  possibility  of  injury 
to  the  gums,  the  anchor  bands  should  not  be  removed  with  scalers  or 
similarly  shaped  instruments.  The  author  has  designed  a  special 
plier,  Fig.  585,  for  the  purpose  of  removing  anchor  bands  from  the 
teeth,  and  by  its  use  bands  may  be  easily  removed  from  the  tenderest 


Fig.  585. 

teeth  without  pain  on  account  of  the  scientific  adaption  of  the  instru- 
ment in  the  utilization  of  a  powerful  leverage  with  the  occlusal  surface 
of  the  anchor  tooth  as  a  fulcrum. 

Wrenches. — As  the  wrench  is  the  most  commonly  used  instrument 
of  the  orthodontist,  it  should  be  so  constructed  that  it  will  represent 
in  material  of  construction,  adaptation  and  finish,  the  most  perfect  of 
instruments.  In  the  first  place,  it  should  be  made  of  steel,  which 
allows  greater  rigidity  with  less  bulk  than  iron.     The  handle  should 


Fig.  586. 

be  octagonal,  giving  a  firm  grip,  and  the  whole  instrument  should  be 
about  5^  inches  long. 

The  socket  ought  not  to  be  deeper  than  the  width  of  the  nut,  and 
should  fit  quite  accurately.  The  arms  of  the  socket  should  be  circular 
in  form  tapering  down  upon  the  handle.  The  wrench  shown  in  the 
upper  part  of  Fig.  586  represents  the  proper  form  of  a  double-ended 
oblique-angled  wrench  for  use  in  turning  the  nuts  on  the  lingual  side 


yiO  ORTHODONTIA. 

of  lower  clamp  bands  only.  The  lower  wrench  in  the  same  cut 
illustrates  the  straight-angled  double-ended  wrench  for  turning  the  nuts 
on  the  expansion  arch,  one  end  being  adapted  for  12-gauge  nuts,  the 
other  for  14-gauge  nuts. 

Ligatures. — After  the  proper  adjustment  of  the  arch  and  molar 
bands  upon  the  teeth,  a  study  of  the  case  should  be  made  with  regard 
to  the  most  advantageous  use  of  the  wire  ligatures,  so  that  the  most 
direct  and  positive  force  may  be  exerted  upon  the  teeth  which  are  to  be 
moved,  and  a  proper  balancing  of  the  lateral  expansive  force  obtained  so 
that  reciprocation  of  force  may  be  secured  from  one  side  of  the  arch  to 
the  other. 

At  the  present  time,  five  sizes  of  ligature  wire  are  in  use  for  this  pur- 
pose, their  respective  diameters  being  .013,  .014,  .015,  .017  and  .018  of 
an  inch. 

For  gentle  traction  force,  the  finest  ligatures  are  most  serviceable, 
especially  in  the  movement  of  the  deciduous  teeth,  and  in  the  ligation 
of  permanent  teeth  at  the  beginning  of  treatment  when  the  proximation 
of  the  surfaces  of  the  adjoining  teeth  render  it  difficult  and  some- 
times impossible  to  use  the  heavier  ligatures.  The  heavier  ligatures 
are  suitable  for  accurate  and  efiQcient  work  in  any  position  where  they 
can  be  used,  their  efficiency  increasing  with  their  diameter. 

The  greatest  usefulness  of  the  ligature  is  obtained  only  when  the 
expansion  arch  is  slightly  free  from  contact  with  the  teeth  to  be  ligated, 
so  as  to  secure  the  fullest  spring  of  the  arch  wire  outward  where 
general  expansion  is  desired. 

Forms  of  Wire  Ligatures.— The  advantages  to  be  gained  by  the 
use  of  a  variety  of  styles  of  ligatures  may  be  understood  from  a  com- 
parative study  of  their  different  methods  of  attachment  to  the  arch 
(Fig.  587)  according  to  the  desirability  of  the  attainment  of  such 
qualities  as  directness  and  positiveness  of  action,  freedom  from  pain, 
and  inconspicuousness  of  appliances  through  the  use  of  the  least 
number  of  bands  upon  incisors,  or  other  teeth. 

This  arrangement  of  ligatures  in  Fig.  587  represents  more  than  the 
actual  number  of  ligatures  that  would  be  used  in  this  particular  case, 
as  the  use  of  the  lingual  wire  extensions  as  far  forward  as  the  first 
bicuspids  would  materially  lessen  the  number  of  as  many  ligatures  as 
are  here  illustrated  on  one  cast  simply  to  show  the  different  varieties. 

Plain  Wire  Ligature. — ^The  plain  wire  ligature  encircling  the  tooth 
and  arch,  is  properly  used  in  ligating  teeth  which  are  to  be  moved  in  a 
straight  line  outward  to  the  arch.  It  is  improperly  used  on  the  bicuspid 
at  A,  Fig.  587,  as  the  tendency  of  either  wire  or  silk  ligatures  on  the 


OPERATIVE    TECHNIC. 


711 


bicuspids  is  to  slip  toward  the  gingivae,  in  which  case  they  might  do 
considerable  injury  to  the  peridental  membrane.  It  is  a  safe  rule  to 
always  band  the  bicuspids  where  it  is  not  advisable  to  use  a  stirrup 
ligature. 

The  Stirrup  Ligature. — ^To  prevent  possible  injury  to  the  soft 
tissues  surrounding  the  teeth  in  ligating  bicuspids,  the  sturup  liga- 
ture, suggested  by  Lourie,  and  shown  in  position  on  the  bicuspid,  at 
D,  Fig.  587,  is  most  efficient,  the  loop  extending  across  the  sulcus  of 
the  bicuspid  and  soft  soldered  to  the  plain  ligature  at  the  mesial  and 


Fig.  587. 

distal  angles  of  the  lingual  surface  of  the  tooth  effectually  preventing 
anv  movement  of  the  ligature  toward  the  gingiva. 

T  Ligature. — ^A  modified  form  of  this  ligature,  known  as  the  T 
ligature,  has  been  devised  by  the  author  for  the  prevention  of  the  slip- 
ping of  ligatures  upon  the  deciduous  teeth,  the  necks  of  which  are  so 
constricted  that  plain  ligatures  invariably  tend  to  slip  beneath  the  gin- 
givae, a  class  of  cases  in  which  the  greatest  care  should  be  taken  that 
there  is  no  injury  or  discomfort  from  this  cause.  The  T  ligature  is  seen 
at  F  and  E,  Fig.  587,  and  is  constructed  by  soft  soldering  one  piece  of 
ligature  wire  at  right  angles  to  another,  the  one  ligature  at  right  angles 


712  ORTHODONTIA. 

being  carried  over  the  occlusal  surface  of  the  tooth  to  engage  in  the 
twist  of  the  other  two  ligature  ends  which  pass  through  the  inter- 
proximate  spaces  to  the  arch  wire,  one  above  and  the  other  below. 

By  forming  a  curved  hook  upon  the  end  of  the  wire  ligatures  befo  re 
inserting,  they  will  easily  pass  through  the  interproximate  space  without 
injury  to  the  gum  tissue,  as  the  ligature  will  follow  this  curve  upward  or 
downward  through  the  space  until  it  reappears  free  from  the  gums  on  the 
lingual  or  buccal  surface  of  the  teeth. 

Ligatures  should  be  pulled  taut  over  the  buccal  surface  of  the  arch, 
and  pressure  between  the  tooth  and  arch  brought  to  bear  with  the  thumb 
and  finger,  the  long  end  of  the  ligature  then  being  grasped  with  the 
left  hand,  and  the  short  end  with  the  arch  and  ligature  pliers  illustrated 
in  Fig.  588,  and  twisted  a  full  turn  to  the  left,  always  preferably  twisting 
in  the  same  direction.  The  ends  of  the  ligatures  should  be  clipped  to 
one-eighth  inch  lengths  and  bent  either  above  or  below  the  arch  to 
positions  where  they  will  cause  no  irritation. 


Fig.  588. 

Arch  and  Ligature  Pliers. — ^The  arch  and  ligature  pliers,  devised 
by  the  author,  have  rounded  beaks  except  the  tips,  so  that  neither  the 
lips  nor  cheek  will  be  caught  between  them  as  in  a  flat-nosed  plier. 
They  are  useful  also  for  bending  the  expansion  arch  to  shape  as  pre- 
viously described. 

Rotating  Wire  Ligatures.— "WTien  the  direction  of  the  tooth  move- 
ment is  forward  and  outward,  especially  if  rotation  is  necessary  at  the 
same  time,  as  in  the  case  of  the  lateral  incisor  at  B,  Fig.  587,  the  band 
with  lingual  spur  should  be  cemented  upon  the  tooth,  and  the  direction 
of  the  ligature  guided  by  the  location  of  a  spur  on  the  arch  wire.  As  soon 
as  the  teeth  which  need  rotation  approach  the  arch  sufficiently  near,  the 
rubber  wedge  should  be  placed  between  the  arch  and  the  nearest  ap- 
proaching labial  angle  of  the  tooth,  as  in  the  manner  of  rotating  the 
central  incisor  at  H  in  the  same  figure. 

In  favorable  cases,  the  band  need  not  be  used,  but  the  double  loop 


OPERATIVE    TECHNIC.  713 

ligature,  shown  at  C,  suggested  by  Angle,  will  be  found  serviceable  in 
rotation. 

Spurs. — Again,  the  effectiveness  of  the  ligature  may  depend  upon 
the  fixedness  and  location  of  its  attachment  to  the  expansion  arch, 
which  may  be  accomplished  by  the  raised  spur  upon  the  surface  of  the 
arch  wire  located  in  such  a  position  as  to  cause  the  movement  of  the 
teeth  in  a  certain  desired  direction. 

In  one  style  of  the  Angle  expansion  arch,  the  same  purpose  is 
accomplished  by  filing  a  notch  in  a  re-enforced  ridge  which  is  on  the 
buccal  surface  of  the  arch  wire,  this  notch  interfering  in  no  way  with 
the  tensile  strength  of  the  wire  since  it  does  not  penetrate  its  surface 
(see  Fig.  589). 


Fig.  589. 

Spur  Pliers. — Spurs  may  be  easily  and  quickly  made  on  the  plain 
arch,  as  shown  in  Fig.  590,  by  means  of  the  spur  pliers  devised  by 
Lourie.  With  this  instrument,  applied  while  the  arch  is  in  position,  one 
may  seize  the  arch  firmly  between  its  two  beaks,  and  by  a  slight  pressure 
upon  the  lever  at  the  side  at  the  same  time,  a  small  chisel  is  forced 
against  the  surface  of  the  wire  at  an  acute  angle,  raising  a  spur  which  is 
hardly  perceptible  to  the  eye,  but  which  is  capable  of  holding  the 
heaviest  ligature  from  slipping. 

When  any  particular  barb  or  spur  is  no  longer  in  use,  it  may  be 
burnished  down  upon  the  surface  of  the  arch  wire,  so  as  not  to  inter- 
fere with  the  lip  or  cheek.  The  spring  of  the  arch  is  not  in  the  least 
impaired  by  the  spurs  made  in  this  manner. 

When  a  longer  and  stronger  spur  is  required  for  the  expansion 
arch,  it  may  be  made  of  a  piece  of  .30  wire  soldered  to  the  arch  wire 
with  18-K.  solder,  and  the  surplus  wire  cut  off,  leaving  a  short  spur 
which  is  polished  with  the  sandpaper  disk. 

An  improved  form  of  ligature  cutting  snips,  the  points  of  the  beaks 


714 


ORTHODONTIA. 


of  which  are  long  and  slender,  allowing  of  very  delicate  work,  is 
illustrated  in  Fig.  591. 

Lingual  Bar  and  Wire  Ligature.— The  alignment  of  the  lower 
incisors  is  sometimes  easily  effected  by  the  use  of  a  lingual  bar    to 


Fig.  590. 

which  is  soldered  one  ligature  to  prevent  displacement,  and  another 
ligature  extending  around  the  bar  and  through  the  interproximate 
space  between  the  central  and  lateral  on  one  side    to  the  arch   wire. 


Fig.  591. 

For  example,  in  A,  Fig.  591,  one  ligature  on  each  side  between  the 
central  and  lateral,  and  encircling  the  lingual  bar,  will  easily  align 
the  incisors  without  the  use  of  a  single  band,  even  where  there  is 
considerable  torsion  of  any  of  these  teeth. 


OPERATIVE   TECHNIC.  715 

Closing  up  Spaces  between  Incisors. — If  it  is  desired  to  close 
up  spaces  between  the  incisors,  the  ligatures  may  be  applied  in  the 
manner  shown  in  Fig.  592  at  B,  the  two  centrals  being  surrounded  by  a 
single  ligature  which  also  encloses  the  arch;  at  the  same  time,  the 
laterals  on  either  side  may  be  similarly  ligated  to  the  centrals. 


Fig.  5q2. 

Extrusion  of  Cuspid. — In  the  extrusion  of  the  cuspid,  the  plain 
band  should  be  formed  high  up  on  the  labial  surface  of  the  tooth, 
soldered  on  this  surface,  and  trimmed  so  that  a  projecting  portion  of 
the  united  ends  of  the  band  material  is  left  for  the  attachment  of  a 
ligature  to  the  arch  as  in  Fig.  593.  This  method  of  attachment  of  the 
ligature  is  to  be  preferred  to  the  spur,  and  saves  the  time  of  soldering 
the  latter  to  the  band. 

The  operator  should  form  the  habit  of  twisting  all  ligatures  in  the 

same  direction,  preferably  to  the  left.     The  liga- 

fW\  x^  ture  wire  may  be  economically  used  by  grasping 

SX/.l       ,       :  the  long  strand  with  the  left  hand  and  the  short 

^''^^t, )  one,  about  two  inches  in  length,  with  the  pliers 

Fig.  503.  ^^  t^^  '"'g'^t   hand,   and  the  twist  should  be  a 

complete  one,  so  as  to  avoid  all  danger  of  its 
being  unloosened  between  sittings. 

In  cutting  oflf  the  surplus  ends  of  the  ligature  wire,  about  one-eighth 
of  an  inch  of  wire  should  be  left,  which  should  be  bent  above  or  below 
and  around  the  arch  where  it  will  not  irritate  the  lips  or  cheek. 

Arrangement  of  Ligatures  for  Mesial  and  Distal  Movements  of 
Incisors. — The  mesial  or  distal  movement  of  incisors  is  often  necessary, 
and  can  be  readily  accomplished  by  the  use  of  the  ligatures  alone  in 
connection  with  spurs  upon  the  arch  for  directing  the  movement  as 
desired,  as  in  Fig.  594.  The  spurs  are  made  upon  the  arch  so  as  to 
incline  the  ligatures  in  the  desired  direction,  mesially  or  distally,  and 
the  nut  at  L  is  tightened,  and  at  M  is  loosened,  causing  the  arch  to  shift 
laterally  in  the  direction  of  the  arrow,  JK,  and  carrying  the  incisors 
with  it.  The  cuspids  and  bicuspids  may  be  similarly  ligated  to  the 
arch  and  share  in  the  movement. 


7i6 


ORTHODONITE. 


Silk  Ligatures. — In  view  of  the  quicker  action  and  greater  com- 
fort of  the  silk  ligature  for  tooth  movement,  it  has  to  some  extent 
displaced  the  wire  ligature  for  the  ligation  of  incisors,  and  cuspids. 
Especially  is  the  silk  ligature  valuable  when  used  for  the  rotation  of 
these  teeth,  for  the  hold  of  the  silk  ligature  upon  the  teeth  is  very  firm 


Fig.  594. 

and  the  amount  of  contraction  of  the  silk  when  moistened  causes  the 
teeth  to  be  rapidly  rotated. 

The  silk  ligature  is  useful  in  the  hands  of  the  skilled  operator,  for 
it  may  be  manipulated  in  such  a  way  as  to  avoid  the  use  of  bands  to  a 
large  extent,  rendering  the  operation  less  painful,  and  the  appearance 
of^the  mouth  more  esthetic  than  when  many  bands  and  metallic 

ligatures  are  used.  These  silk  liga- 
tures may  be  obtained  in  at  least  four 
sizes,  the  smaller  of  which  are  prefer- 
able for  the  average  case. 

Rotating  Silk  Ligatures. — ^To 
correctly  place  a  silk  ligature  upon  an 
incisor,  for  the  purpose  of  rotation  of 
the  tooth,  the  method  of  procedure  is 
as  follows: — ^First  take  a  double 
strand  of  the  silk,  and  doubling  it 
upon  itself,  slip  the  two  ends  through 
the  loop  formed  thereby,  as  at  A, 
Fig.  595.  Next,  place  this  slip  noose 
thus  formed  over  the  incisor  in  such  a  way  that  the  noose  may  be 
tightened  towards  the  angle  of  the  tooth  which  is  to  be  turned,  as 
at  B,  Fig.  595.  Separate  the  strands  and  draw  them  taut  alternately 
in  opposite  directions.     Finally  pass  both  strands  through  the  proxi- 


FiG.  595. 


OPERATIVE   TECHNIC. 


717 


mate  space  nearest  the  angle  of  the  incisor  to  be  labially  turned,  pass- 
ing one  strand  above,  the  other  below  the  expansion  arch,  tying  them 
together  with  a  surgeon's  knot,  as  at  C,  Fig.  595. 

It  is  advisable  to  band  the  bicuspids  and  attach  the  silk  ligature 
to  a  lingual  spur  to  avoid  the  slipping  of  the  silk  ligature  towards  the 
gingivae  as  happens  when  the  ligature  is  applied  to  the  unhanded  tooth. 

Measuring  the  Force  of  Expansion. — In  the  use  of  the  expansion 
arch  it  is  possible  to  exert  varying  degrees  of  expansive  force  according 
to  the  degree  of  bending  of  the  ends  of  the  arch  buccally  from  the  posi- 
tion in  which  they  rest  passively  in  the  buccal  tubes  of  the  anchor 
bands. 

In  the  drawing,  Fig.  596,  is  represented  a  method  of  determining 
by  means  of  a  spring  balance  the  degree  of  expansive  force  exerted 
by  the  arch.     The  expansion  arch  on  the  right  is  slipped  into  short 


76    5^3*^10  ^=== 

— H] 

=  90  = 

i 

11 

Fig.  596. 


tubes  soldered  respectively  to  the  end  of  the  balance  and  to  the  indicator 
point.  If  the  o  mark  registers  the  passive  position  of  the  expansion 
arch  in  the  buccal  tubes  when  no  expansion  is  desired,  the  figures  i,  2, 
3,  etc.,  will  register  any  degree  of  expansive  force  put  into  the  arch  by 
bending,  so  that  the  degree  of  expansive  force  may  be  expressed  some- 
what accurately,  as  follows: 

o — Passive. 

1/8  pound — Slight  expansive  force. 

1/4  pound — Medium  expansive  force. 

1/2  pound — Strong  expansive  force. 

From  3/4  of  a  pound,  and  points  beyond,  would  be  represented  ex- 
treme potential,  which  can  be  recorded;  as,  for  example,  it  might  be 
recorded  that  an  arch  was  placed  in  position  with  an  expansive  force 
of  I  1/4  pounds,  etc. 


7 1 8  ORTHODONTIA . 

The  expansion  arch  slipped  into  tubes  on  the  left  side  of  the  spring 
balance  would  register  the  amount  of  force  it  might  be  desired  to  exert 
lingually,  indicated  by  the  same  numerals. 

It  must  not  be  forgotten,  however,  that  two  arches  of  the  same  gauge 
may  be  longer  and  shorter  to  fit  the  case,  and  the  shorter  arch  will  register 
a  proportionately  greater  force  with  its  two  ends  separated  the  same 
distance  as  the  longer  arch,  because  a  shorter  spring  exerts  a  greater 
force  than  a  longer  spring,  the  gauge  of  the  wire  and  the  material  of 
construction  being  the  same  in  each  case. 

Hence,  the  necessity  of  measuring  the  length  of  an  arch  as  by  the 
scale  before  registering  its  force.  Both  items  should  be  made  a  matter 
of  record,  so  that  somewhat  accurate  knowledge  of  the  power  of  the 
forces  used  may  be  known.  This  idea  of  the  spring  balance  was  first 
suggested  by  Hawley  for  determining  the  comparative  elasticity  of 
precious  metal  expansion  arches  and  base  metal  arches. 

Bilateral  Expansion  of  the  Dental  Arch. — ^In  adjusting  the 
expansion  arch  for  inclination  movement  in  bilateral  and  anterior 
expansion  of  the  dental  arch,  after  the  proper  precautions  have  been 
observed  in  aligning  the  buccal  tubes  and  bending  the  expansion  arch 
so  that  the  ends  rest  passively  in  the  tubes  without  a  tendency  to  rotate 
the  anchor  teeth,  a  slight  expansive  force  of  about  1/3  pound  should 
be  used  at  the  beginning  and  increased  only  if  the  degree  of  resistance  to 
be  overcome  demands  it. 

The  tendency  of  the  amateur  is  to  give  the  expansion  arch  too 
much  lateral  spring  when  first  applied,  and  to  force  the  incisors  and 
cuspids  forward  by  turning  up  the  nuts  in  front  of  the  anchor  tubes, 
too  frequently,  instead  of  performing  sufficient  lateral  expansion, 
both  anteriorly  and  posteriorly. 

It  is  advisable  in  any  case,  to  adjust  the  expansion  arch  to  its  posi- 
tion for  a  few  days  without  any  lateral  spring  in  it,  so  as  to  allow  the 
patient  to  become  used  to  the  bulk  alone  at  first,  and  afterward, 
gradually  increase  the  lateral  spring  to  suit  the  requirements  of  the 
case. 

In  the  expansion  of  the  anterior  portion  of  the  arch  only,  for  moving 
one  or  more  incisors  into  normal  positions  it  is  necessary  to  have  but 
little  lateral  spring  in  the  expansion  arch,  and  it  should  conform  to  the 
labial  surfaces  of  the  incisors  and  cuspids,  and  the  arch  extremities, 
resting  passively  in  the  buccal  tubes,  but  in  severe  cases,  and  in  those  in 
which  considerable  lateral  development  is  desired,  the  bow  of  the 
expansion  arch  should  be  flattened  with  the  arch  and  ligature  pliers 
so  as  to  form  a  longer  arc,  the  ends  of  the  arch  slipping  into  the  anchor 


OPERATIVE   TECHNIC.  719 

tubes  with  the  lateral  tension  gauged  according  to  the  amount  of 
posterior  expansion  indicated  by  diagrammatic  measurements. 

Whenever  it  is  necessary  to  provide  for  considerable  anterior  ex- 
pansion, such  as  in  a  case  in  which  the  laterals  are  in  lingual  occlusion, 
it  will  always  be  found  necessary  to  expand  posteriorly  as  well,  and  in 
fact  the  Hawley  diagrams  of  the  pre-determined  arch  indicate  anterior 
and  posterior  expansion  in  many  cases,  and  the  arch  should  be  bent  so 
that  it  will  have  sufficient  lateral  spring  to  meet  the  requirements  of 
the  case,  remembering  that  the  difference  in  resisting  power  of  the  teeth 
and  alveolar  process  is  varied  according  to  the  age  of  the  patient  and 
number  of  permanent  teeth  present.  The  adult  dental  arch  will  resist 
an  expansive  force  which  would  be  impossible  to  use  in  the  case  of  an 
arch  in  which  the  deciduous  teeth  were  not  all  shed. 


Fig.  597. 

Fig.  597  illustrates  an  expansion  arch  in  position  in  an  adult  case 
in  which  both  anterior  and  posterior  expansion  are  necessary.  The 
expansion  arch  is  located  a  few  millimeters  from  the  incisor  teeth,  so 
that  as  the  anterior  portion  of  the  expansion  arch  moves  Hngually  as 
its  extremities  move  buccally,  the  incisors  will  not  be  forced  lingually. 
Turning  up  the  nuts  slightly  and  religating,  or  tightening  the  ligatures 
on  the  incisors  at  each  visit  of  the  patient  will  keep  the  incisors  in  a 
new  arc  of  expansion,  while  space  is  being  made  for  the  laterals  in 
lingual  occlusion  by  the  proper  direction  of  these  ligatures  through 
spurs  e,f,g,  and  h,on  the  arch  wire,  and  on  the  incisorand  cuspid  bands. 

The  author  has  found  it  advantageous  and  conservative  of  anchor- 
age to  perform  anterior  expansion  in  advance  of  very  much  posterior 
expansion   in  many  cases,  since  the  resistance  power  of  the  molar 


720  ORTHODONTIA. 

anchorage  is  only  opposed  in  one  direction  througii  the  turning  up  of 
the  nuts  in  front  of  the  anchor  tubes,  while  in  performing  anterior 
and  posterior  expansion  simultaneously,  the  resistance  power  of  the 
molar  anchorage  is  being  opposed  in  a  lateral  as  well  as  a  distal  direc- 
tion, tending  to  make  it  more  unstable  than  by  the  other  method. 

Fig.  598  exhibits  a  case  in  which  considerable  lateral  expansion  of 
the  dental  arch  is  necessary.  By  using  upon  the  deciduous  molar  a 
screw  clamp  band  with  a  lingual  wire  extension,  as  seen  in  the  cut,  the 
lingual  screw  may  be  allowed  to  rest  against  the  first  permanent  molar, 
and  the  lingual  wire  may  rest  against  the  lingual  surfaces  of  the  other 
deciduous  teeth,  when,  by  ligation  to  the  expansion  arch,  the  entire 
resistance  of  each  lateral  half  of  the  dental  arch  may  be  pitted  against 
the  other  lateral  half  in  bilateral  expansion. 

This  control  of  the  anchorage  resistance  enables  a  greater  force  of 


Fig.  598. 

expansion  to  be  used  than  otherwise,  and  is  more  comfortable  than  the 
usual  method  of  ligating  each  tooth  in  each  lateral  half.  The  incisors 
in  this  case  were  banded  in  order  that  ligatures  might  be  more  securely 
placed,  and  thereby  lose  none  of  the  force  of  the  appliance. 

In  the  use  of  ligatures  on  incisors,  and  extending  from  the  arch  to 
the  lingual  wire  extensions,  as  well  as  in  the  use  of  round  buccal  tubes 
on  the  clamp  bands,  inclination  movement  of  the  teeth  is  secured.  The 
development  of  the  arch  anteriorly  is  secured  by  turning  up  the  nuts 
against  the  anchor  tubes  on  each  lateral  half. 

In  Fig.  599  is  shown  a  somewhat  similar  reciprocation  of  force  and 


OPERATIVE   TECHNIC. 


721 


anchorage  resistance,  using  plain  molar  bands,  with  lingual  extensions 
to  the  deciduous  cuspids.  This  use  of  lingual  wire  extensions  from  the 
anchor  bands  seems  to  be  the  most  ideal  combination  that  the  author  has 
used,  so  far  as  efi5ciency  and  comfort  for  the  patient  is  concerned.  With 
this  combination  there  is  no  loss  of  resistance  at  any  point;  the  first 
molar  cannot  move  buccally  before  the  deciduous  teeth,  as  often  hap- 
pens, and  the  lateral  expansion  takes  place  uniformly  and  with 
precision. 

In  this  case  the  incisors  are  not  banded  and  are  ligated  with  silk 
ligatures.  A  single  ligature  from  the  expansion  arch  to  a  loop  on  a 
deciduous  molar  band  or  to  the  lingual  wire  extension  on  each  lateral 
half  controls  all  of  the  deciduous  teeth  in  their  buccal  movements. 


Fig.  599. 


In  order  to  secure  bodily  movement  or  stationary  anchorage  of  the 
anchor  teeth  in  this  case  it  is  necessary  to  use  non-rotating  tubes  of 
oval  shape. 

Unilateral  Expansion  of  the  Dental  Arch. — It  is  often  necessary 
in  cases  of  lingual  occlusion  of  one  lateral  half  of  the  upper  dental  arch, 
as  in  Fig.  600,  to  pit  all  of  the  resistance  of  the  teeth  in  the  normally 
related  half  against  that  of  one  tooth  at  a  time  in  the  half  in  lingual 
occlusion.  Fig.  601  illustrates  the  expansion  arch  in  position  on  the 
upper  arch  of  this  case  for  unilateral  expansion.  The  lingual  wire 
extension  on  the  clamp  band  ligated  to  the  expansion  arch  distal  to 
the  cuspid  secures  the  resistance  of  the  cuspid;  deciduous  and  per- 
manent molars  on  the  one  side,  aided  by  the  use  of  an  oval  buccal  tube 
on  the  molar  clamp  band  on  the  other  side;  the  permanent  molar  alone 
46 


722  ORTHODONTIA. 

is  banded ;  the  expansion  arch  fitting  in  a  round  buccal  tube  to  lessen 
the  resistance  to  buccal  movement. 


Fig.  600. 


Enough  resistance  is  thus  obtained  on  the  normally  related  half  to 
move  first  the  permanent  molar  and  then;  consecutively,  by  ligating  to 


Fig.  601. 


the  expansion  arch;  the  deciduous  molar  and  cuspid  into  normal  rela- 
tions of  occlusion;  provided  sufficient  expansive  force  is  given  to  the 


OPERATIVE   TECHNIC.  723 

expansion  arch.  Occasionally  it  will  be  necessary  to  use  intermaxillary 
force  as  an  anchorage  re-enforcement  as  shown  in  Fig.  53 1 ,  in  order  to 
accomplish  the  desired  result  in  unilateral  expansion. 

Distal  Movement  of  Molars. — Oftentimes  it  is  necessary,  in 
opening  up  spaces  for  extracted  first  molars,  to  pit  the  resistance  of  the 
ten  anterior  teeth  against  that  of  the  second  molars,  which,  in  these 
cases,  usually  drift  forward  into  the  space  of  the  lost  first  molars, 
and  must  be  moved  distally  by  a  proper  manipulation  of  force  and 
anchorage. 

The  reversal  of  the  base  of  anchorage  from  the  molars  to  the  anterior 
teeth  for  the  distal  movement  of  the  molars,  may  be  effected  by  ligating 
a  sufl5cient  number  of  the  anterior  teeth  to  the  arch  so  that  their  com- 
bined resistance  will  be  greater  than  that  of  the  molars  to  be  moved 
distally. 


Fig.  602. 

The  combined  resistance  of  the  ten  anterior  teeth,  as  secured  through 
ligation  to  the  expansion  arch  as  at  a,  b,  c,  d,  e,  f,  g,  and  h  in  Fig,  602, 
is  greater  than  that  of  the  second  molars  to  distal  movement,  and 
turning  up  the  nuts  in  front  of  the  anchor  tubes  will  force  the  molars 
distally  and  regain  the  spaces  of  the  lost  first  molars  provided  the  molar 
anchorage  is  made  as  nearly  a  pivotal  anchorage  as  possible.  The 
resistance  to  distal  movement  of  the  molars  is  thus  very  much  lessened 
by  the  use  of  the  pivotal  tube  anchor  band,  Fig.  578.  To  prevent  the 
ligatures  from  slipping  upon  the  expansion  arch  in  the  region  of  the 
bicuspids,  spurs  should  be  soldered  upon  the  arch  and  the  ligatures 
attached  in  front  of  them  as  at  a  and  b,  thus  securing  the  positive 
resistance  of  the  second  bicuspids.  The  proximate  contact  of  the 
second  with  the  first  bicuspids  will  suffice  to  obtain  the  resistance  of 


724 


ORTHODONTIA. 


these  teeth  in  line  with  the  required  movements  without  bands  and  spurs 
to  attach  ligatures.  The  arrows  indicate  the  direction  of  tooth  move- 
ment, in  the  region  of  least  resistance,  or  the  distal  movement  of  the 
second  molar  teeth. 

Hooks  may  be  attached  to  the  expansion  arch  for  the  use  of  inter- 
maxillary anchorage,  extending  the  elastic  rubbers  from  hooks  on  the 
lower  expansion  arch  to  the  distal  ends  of  the  anchor  tubes  of  the  upper 
expansion  arch,  in  case  the  resistance  of  the  single  molars  should  prove 
to  be  greater  than  that  of  the  ten  anterior  teeth,  thus  preventing 
misdirected  movement. 

As  there  may  often  be  found  in  these  cases  some  distal  positions 
of  the  anterior  teeth  as  a  whole,  having  traveled  distally  towards  the 
space  of  the  lost  molars,  it  may  be  found  necessary  to  use  the  second 
molars  as  simple  anchorage  at  first,  using  a  soldered  buccal  tube  on 
the  molar  band,  and  successively  move  the  anterior  teeth  forward, 


Fig.  603. 

ligating  and  moving  the  two  centrals,  then  the  two  laterals,  the  cuspids 
next,  and  so  on,  turning  up  the  nuts,  in  front  of  the  anchor  tubes  and 
later  reversing  the  anchorage  to  the  anterior  teeth  for  the  distal 
movement  of  the  molars  as  soon  as  the  necessary  anterior  movement 
of  the  incisors  and  cuspids  is  complete. 

Tipping  up  Molars. — In  simpler  cases  than  that  just  described, 
in  which  the  first  molars  have  been  lost  and  the  second  molars  have 
but  slightly  usurped  the  first  molar  spaces,  the  forward  tipping  requires 
an  especial  adjustment  of  the  anchorage  to  effect  the  restoration  of 
the  second  molars  to  upright  positions. 

The  soldered  tubes  upon  the  anchor  bands  should  first  be  so 
inclined  and  aligned  that  the  ends  of  the  expansion  arch  may  be  easily 
inserted  into  them,  when  the  bow  of  the  arch  rests  upon  the  gums 
below  the  incisor  teeth,  as  in  Fig.  603. 

By  springing  the  front  of  the  arch  upward  upon  the  necks  of  the 
incisor  teeth  and  ligating  these  teeth  to  the  arch  at  the  same  time,  an 


OPERATIVE   TECHNIC.  725 

upward  leverage  will  be  exerted  upon  the  second  molars  which  will 
soon  restore  them  to  an  upright  position. 

Rotation  of  Molars. — Several  methods  are  in  use  for  the  rotation 
of  molars  in  torso-occlusion.  In  the  rotation  of  a  molar  which  has 
its  mesio-buccal  cusp  farther  buccally  than  the  disto-buccal  cusp, 
the  expansion  arch,  bent  as  at  E  in  Fig.  567  before  slipping  into  the 
buccal  tube  on  the  clamp  band  encircling  the  molar,  answers  the 
purpose,  especially  as  the  desired  change  of  position  of  the  molar 
is  in  line  with  the  buccal  movement  of  the  expansion  arcli,  the  distat 
end  traveling  farther  buccally  than  a  point  on  the  arch  opposite  the 
mesio-buccal  cusp  of  the  molar. 

The  reverse  of  this  position,  or  the  molar  with  the  mesio-buccal 
cusp  farther  lingual  than  the  disto-buccal  cusp,  is  not  so  amenable 
to  change  in  the  desired  direction  by  the  lingual  bending  of  the  ends 
of  the  expansion  arch,  since  the  tendency  of  the  arch  in  its  outward 
movement  is  to  move  the  disto-buccal  cusp  farther  buccally  in  relation 
to  the  mesial  cusp,  in  spite  of  the  lingual  bending  of  the  arch  to 
prevent  it. 

A  method  devised  by  J.  L.  Young  for  effecting  the  rotation  of  the 
molar,  is  illustrated  in  Fig.  604,  the  two  sides  of  the  dental  arch  being 
treated  slightly  different. 

On  one-half  of  the  arch,  a  clamp  band,  with  its  lingual  screw 
directed  distally,  is  fitted  to  the  molar  in  torso-occlusion,  and  on  that 
part  of  the  band  corresponding  to  the  mesio-buccal  angle,  a  short 
tube  is  soldered  parallel  to  the  long  axis  of  the  tooth,  as  shown  in 
position  on  the  clamp  band  on  the  right  side  of  the  cut.  A  short  wire 
fitting  into  this  tube  snugly,  is  then  soldered  at  right  angles  to  the 
surface  or  to  the  end  of  an  arch  or  tube.  The  attachment,  when  m 
position,  forms  a  hinged  anchor  tube  for  the  expansion  arch  at  the 
mesio-buccal  angle  of  the  molar,  as  illustrated. 

The  cuspid  on  the  same  side  as  the  molar  to  be  rotated  is  fitted 
with  a  band  and  a  lingual  hook  pointing  mesially,  and  a  rubber 
band  of  sufficient  strength  attached  from  this  hook  to  the  lingual 
screw  of  the  molar  clamp  band,  as  seen  on  the  lingual  side  of  the  arch 
in  the  illustration.  The  cuspid  should  be  firmly  ligated  to  the  arch 
so  as  to  prevent  its  distal  or  rotary  movement  during  the  operation. 
When  the  nut  on  the  expansion  arch  is  tightened,  the  tendency  to 
distal  movement  of  the  mesio-buccal  angle  of  the  molar,  and  the 
reciprocating  action  of  the  elastic,  pulling  the  disto-lingual  angle 
mesially,  exerts  the  most  positive  rotating  action  upon  the  molar  in 
the  desired  direction. 


726  ORTHODONTIA. 

A  slight  variation  from  this  method  is  illustrated  on  the  other 
side  of  the  same  arch  on  the  left  side  of  the  cut.  The  expansion  arch 
is  attached  to  the  mesio-buccal  surface  of  the  molar  band  by  a  ball 
and  socket  joint,  allowing  a  little  more  freedom  of  movement  of  the 
molar  in  its  rotary  movement. 

A  rigid  hook  is  soldered  to  the  expansion  arch,  curving  between 
the  cusps  of  the  cuspid  and  first  bicuspid  on  the  same  side  of  the  arch, 
and  extending  up  close  to  the  palate,  with  the  end  of  the  hook  pointing 
mesially.  A  rubber  band  of  suitable  strength  is  next  attached  from 
this  hook  over  the  lingual  screw  of  the  clamp  band  on  the  molar  to  be 
rotated  as  shown  in  the  same  cut. 


Fig.  604. 

In  this  method,  in  which  the  attachments  are  all  made  to  the 
expansion  arch,  the  reciprocation  of  force  is  almost  absolute  from  the 
mesio-buccal  angle  of  the  molar  to  the  disto- lingual  angle,  in  the 
rotary  force  exerted  by  the  two  opposite  acting  forces  on  each  side. 

Rotation  of  Teeth  with  Levers. — ^The  principle  of  the  lever  is  a 
very  old  one  in  its  application  to  the  dental  arch,  but  there  is  no  doubt 
that  its  use  alone  as  a  mechanical  appliance  for  the  correction  of 
malocclusion  is  a  misapplication  of  an  otherwise  efficient  mechanical 
principle  when  properly  used. 

For  example,  in  the  old  method  of  using  the  lever,  Fig.  605,  the  prin- 
ciple of  arch  expansion  to  make  space  for  a  rotated  tooth  before  at- 
tempting to  turn  it  into  position  was  not  recognized.  The  fulcrum  of 
the  lever  is  at  N,  the  weight  at  K,  and  the  power  at  G-H.  The  two 
arrows,  i  and  2,  indicate  the  direction  of  the  turning  tooth,  and  it  will 


OPERATIVE    TECHNIC. 


727 


be  seen  that  the  arch  becomes  more  contracted,  if  anything,  during 
the  process,  the  distance,  E-F,  from  cuspid  to  cuspid  remaining  the 
same,  thus  preventing  the  alignment  of  the  incisors,  the  combined 
mesio-distal  diameters  of  which  are  greater  than  the  arc  of  the  arch 
from  one  cuspid  to  the  other. 

The  proper  use  of  the  lever  in  this  case  should  be  as  an  auxiliary, 
the  principal  movements  indicated  being,  first;  general  arch  expansion, 
so  that  the  incisors  may  have  space  for  alignment;  and  second,  rotation 


Fig.  605. 


Fig.  606. 


of  individual  teeth  which  are  turned,  as  illustrated  by  the  combination 
of  the  expansion  arch  and  lever  in  Fig.  606. 

By  ligating  the  incisors  and  cuspids  to  the  arch,  at  A,  C,  B,  D,  etc., 
the  space  for  the  lateral  in  torso  occlusion  is  gradually  made,  while  the 
arch  lever,  L,  at  the  same  time  is  turning  the  tooth  into  position  of 
correct  alignment.  The  arch  lever  may  be  made  of  gold  and  platinum 
or  iridio-platinum,  and  should  have  a  hook  at  one  end  to  engage  with 
the  arch,  so  as  to  dispense  with  tying 
it  (Fig.  528). 

Extruding  Bicuspids  with  Aux- 
iliary Spring. — Occasionally  it  is 
necessary  to  use  an  auxiliary  spring  in 
connection  with  the  expansion  arch  to 
perform  certain  special  tooth  move- 
ments. An  example  of  this  kind  is 
seen  in  the  auxiliary  spring.  Fig.  607,  for  extruding  the  bicuspids,  a 
method  described  and  illustrated  by  J.  L.  Young.  The  auxiliary 
spring  is  soldered  near  the  distal  end  of  the  buccal  tube  on  the  anchor 
band,  extending  forward  and  obliquely  upward  so  that  it  can  be  sprung 
down  and  ligated  to  spurs  on  bicuspid  bands  or  caught  under  hooks 


Fig.  607.     (Young.) 


728 


ORTHODONTIA. 


soldered  to  these  bands.     The  expansion  arch  is  firmly  ligated  to  the 
incisors  so  as  to  re-enforce  the  molar  anchorage. 

Extruding  Bicuspids  and  Intruding  Incisors  with  the  Expansion 
Arch. — In  many  cases  of  deep  overbite  of  the  incisors  it  is  necessary  to 
extrude  the  bicuspids  and  intrude  the  incisors  in  order  to  establish  the 
correct  occlusal  plane.  Fig.  608  illustrates  the  method,  originated  by 
C.  S.  Case,  of  using  a  light  expansion  arch  as  a  double  elastic  lever, 
passing  under  hooks  on  bicuspid  bands  and  over  hooks  on  incisor  bands, 


Fig.  608. 

the  turning  up  of  the  nuts  on  the  expansion  arch  allowing  for  lengthen- 
ing the  arch  at  the  same  time. 

Treatment  of  Infra-occlusion. — The  most  common  form  of 
infra-occlusion  presenting  in  practice  is  that  in  which  there  is  lack 
of  occlusion  of  the  anterior  teeth,  varying  in  degree  from  a  slight 
infra-occlusion  of  one  or  more  incisors  to  those  cases  in  which  the  upper 

and  lower  incisors  are  more  than  half  an 
inch  apart  when  the  molars  are  occluding. 
The  simple  cases  of  infra  occlusion  of 
the  incisors  may  be  easily  managed  by 
bending  the  expansion  arch  downward 
before  placing  it  in  position,  as  in  dotted 
lines  in  Fig.  609,  and  then  springing  it  up- 
ward to  ligate  the  incisors  to  it  after  it  is 
in  position.  The  incisors  may  be  banded, 
with  labial  spurs  for  more  direct  appli- 
Further  treatment  of    infra-occlusion  is    de- 


FlG   609 


cation   of   the  force. 

scribed  under  treatment  of  Class  I  and  II. 

The  Sectional  Arch  and  its  Advantages. — ^The  sectional  arch, 
consisting  of  a  central  unthreaded  portion,  and  two  threaded  end  sec- 


OPERATIVE   TECHNIC. 


729 


tions,  Fig.  610,  was  designed  by  Angle  for  the  especial  purpose  of 
securing  bodily  movement  of  the  teeth  in  dental  arch  expansion.  The 
principle  of  this  appliance  depends  upon  the  use  of  a  very  fine  gauge 
(.30  inch)  arch  wire  to  which  are  soldered  delicate  pins  (.22  inch), 
accurately  fitting  in  vertically  attached  tubes  on  incisor,  cuspid,  or 
bicuspid  bands  (Fig.  610).  This  gives  a  bodily  control  of  the  teeth' so 
that  they  may  be  moved  forward  or  outward  bodily  by  means  of  the 
screw,  or  as  preferred  by  some  operators,  by  straightening  out  loops 
in  the  arch  wire.     With  the  use  of  the  threaded  extremities,'  fitting 


Fig.  610. 


Fig.  611. 

into  horizontal  buccal  tubes,  it  is  necessary  to  have  the  arch  made  in 
three  sections  so  that  the  end  sections  may  be  slipped  back  in  the 
horizontal  plane  into  the  buccal  tubes,  and  the  pins  of  the  middle  sec- 
tion of  the  arch  slipped  out  of  the  tubes  in  the  vertical  plane. 

The  middle  sections  are  made  in  three  different  lengths  for  different 
sizes  of  dental  arches,  Fig.  611,  and  are  squared  at  the  extremities  to  fit 
square  sockets  of  the  end  sections  to  provide  against  rotation.  The  non- 
rotation  principle  is  carried  still  further  in  the  flattening  of  one  side  of 
the  end  sections,  and  one  side  of  the  buccal  tubes  (Fig.  612). 

Fig.  614  illustrates  the  Angle  sectional  arch  in  position  for  the 
bodily  movement  of  the  incisors,  as  described  by  J.  L.  Young.     It  wiU 


730 


ORTHODONTIA. 


be  observed  that  the  .30  inch  arch  wire  is  fitted  closely  into  each  em- 
brasure and  to  the  curved  labial  surfaces  of  the  teeth,  and  that  a  loop 
is  inserted  in  the  middle  section  anterior  to  the  screw  section,  the  flatten- 
ing out  of  this  loop  assisting  in  elongating  the  arch  wire,  in  addition  to 
the  use  of  the  screw  power  for  this  purpose.* 

These  bends  and  loops  in  the  arch  wire  are  made  with  a  special  pair 
of  pliers,  illustrated  in  Fig.  522  and  previously  described. 


Fig.  6i2. 


Fig.  613. 


Banding  the  Teeth  in  the  Use  of  the  Sectional  Arch  in  Perma- 
nent Dentures. — The  use  of  the  sectional  arch  requires  the  careful 
banding  of  every  one  of  the  anterior  teeth  requiring  bodily  movement. 
The  band  material  should  be  made  of  iridio-platinum  or  gold  and 
platinum,  .003  inch  in  thickness,  and  of  an  average  width  of  .19  inch. 
Fig.  613  shows  the  proper  position  of  the  bands  on  the  teeth,  the 
pinched  joint  being  made  on  the  lingual  side,  and  the  bands  festooned 
and  fitted  just  under  the   gingivae.     The   roughening    of   the   surface 


Fig.  614.     (After  Young.) 

of  the  band  "material  with  a  flat  file  secures  a  better  attachment  of  the 
cement  so  that  the  bands  will  not  be  accidentally  loosened. 

The  tubes  are  paralleled  with  the  calipers  (Fig.  504)  vertically  and 
aligned  horizontally  before  soldermg  so  that  there  is  space  enough  on 
the  incisal  edge  of  the  bands  for  the  arch  wire. 

*  The  complete  technic  of  the  Angle  sectional  arch  from  which  the  author  has  briefly 
outlined  the  text  is  fully  described  in  the  following  recent  papers: 

Evolution  of  Orthodontia — Recen  Developments  (Angle),  Dental  Cosmos,  August,  1912, 
Further  steps  in  the  Progress  of  Orthodontia  (Angle),  Dental  Cosmos,  January,  1913. 

Technic  of  the  Practical  Application  of  the  New  Angle  Appliance  (Young),  Items  of 
Interest,  November,  1913,  Treatment  of  Malocclusion,  Angle's  New  Appliances  (Butler) 
Dental  Cosmos,  May,  1914. 


OPERATIVE   TECHNIC.  73 1 

Adjusting  the  Arch  Wire  and  Pins. — Beginning  at  one  side  of  the 
dental  arch,  preferably  the  left,  the  arch  wire,  after  being  annealed,  is 
fitted  into  the  socket  of  the  end  section,  a  loop  provided  for  anterior  to 
this,  if  desired,  and  the  wire  bent  to  conform  to  the  tooth  surfaces  and 
embrasures  up  to  the  mesial  angle  of  the  first  tooth  to  be  attached  with 
the  pin  and  tube.  A  fine  mark  is  made  on  the  arch  wire  opposite  the 
center  of  the  bore  of  the  tube  on  this  band,  the  pin  being  attached  at 
this  point  at  the  proper  angle  of  inclination.  The  arch  wire  is  con- 
formed to  the  surface  of  the  next  tooth,  marked,  and  the  next  pin  at- 
tached, and  so  on,  until  all  the  pins  have  been  attached  and  the  arch 
fitted  in  place  as  in  Fig.  614. 

The  arch  wire  has  a  loop  formed  anterior  to  the  end  section  corre- 
sponding to  the  loop  on  the  opposite  side,  and  the  squared  end  cut  off  to  a 
proper  length  to  just  telescope  in  position  in  the  socket  of  the  end  section. 
The  middle  section  should  be  annealed  to  a  cheiTy  red  and  cooled  in  air, 
polished  and  inserted  passively  in  its  position  with  the  pins  locking  in  the 
tubes  until  the  next  sitting.  If  the  bends  in  the  delicate  pins  should 
have  straightened  out  by  the  frequent  insertion  in  the  tubes  during  the 
fitting  process,  the  pins  should  be  re-bent  to  their  original  shape  before 
tempering  so  that  they  will  lock  in  the  labial  tubes. 

Manipulation  of  the  Sectional  Arch  in  Treatment.— In  simple 

cases  the  middle  section  may  be  left  in  position  in  the  tubes  for  months, 

and  the  entire  bodily  movement  of  the  incisors  controlled  by  turning 

up  the  nut  in  front  of  the  buccal  tubes  or  straightening  out  the  loops  until 

the  appliance  feels  snugly  but  not  painfully  tight.  In  more  complicated 

cases,  it  is  necessary  to  remove  the  middle  section 

and  change  its  shape  at  certain  points  calculated 

to  produce  special  tooth  movements.     Only  one 

of   the    bends   in  the  arch  wire    which,  when 

Fig.  615. 

straightened  out  cause  labial  movement  of  the  in- 
cisors, should  be  changed  at  each  sitting,  leaving  the  rest  of  the  appli- 
ance with  the  pins  in  perfect  register  until  the  next  sitting. 

Rotation  of  Incisors. — In  rotation  of  incisors,  the  tube  is  located 
toward  the  more  lingual  angle,  Fig.  615,  and  the  middle  section  is  bent 
so  that  it  rests  on  the  most  prominent  labial  angle  of  the  tooth  to  be 
rotated  when  the  pin  lies  on  the  labial  side  of  the  tube  of  the  same 
tooth. 

Bending  of  Loops. — ^The  larger  bends  in  the  middle  section  in  the 
form  of  loops  should  be  sligthly  straightened  out,  when  necessary,  in 
such  a  way  that  the  end  of  the  middle  section  will  always  preserve  its 
alignment  with  the  end  section. 


732 


ORTHODONTIA. 


For  example,  if  a  loop  is  pinched  at  a,  Fig.  6i6,  a  controlling  pinch 
should  be  made  at  b  and  at  the  opposite  angle  of  the  loop  so  that  the 
alignment  of  the  arch  wire  at  d  and  e  will  remain  the  same.  In  the 
small  bends  in  the  arch  wire  also,  if  they  are  pinched  to  straighten  them 
out,  a  controlling  bend  should  be  made  so  that  the  general  alignment 
of  the  arch  wire  is  not  changed.  If  an  outward  bend  is  made  at  one 
point,  an  inward  bend  should  be  made  nearby  as  a  control  bend.  Oc- 
casionally the  arch  wire  will  need  to  be  twisted  on  itself  to  restore 
alignment  or  to  give  a  different  angle  of  inclination  to  one  of  the  pins. 
In  these  cases,  two  pairs  of  the  pliers  shown  in  Fig.  522  should  be  used, 
one  to  hold  the  arch  wire,  the  other  to  twist  it.     In  twisting  the  arch 

wire  on  both  sides  of  a  pin,  care  must 
a  be  taken  to  restore  the  original  alignment 

of  the  remainder  of  the  arch  wire  as  as- 
certained by  the  subsequent  fitting  of 
the  pins  not  re-aligned  in  the  tubes. 

Bodily  Lingual  Movement  of  In- 
cisors.— ^The  positions  of  the  pins  are 
sometimes  reversed  in  Class  III  cases  in 
which  it  is  desired  to  move  the  roots  of 
the  lower  incisors  lingually,  the  notches  of  the  pins  locking  on  the  lin- 
gual edges  of  the  tubes  (j.  L.  Young). 

Bodily  Mesial  and  Distal  Movements  of  Anterior  Teeth. — In  the 
mesial  or  distal  movement  of  the  anterior  teeth  with  the  sectional  arch, 
but  one  tooth  at  a  time  should  be  moved  by  resoldering  the  pin  the  thick- 


FlG.  616. 


Fig.  617.    {Young.) 


ness  of  the  wall  of  its  tube  mesially  or  distally  as  the  case  'may'>be,  leav- 
ing the  other  pins  untouched  so  that  the  other  anterior  teeth  may  be  used 
as  anchorage  in  the  lateral  movement  of  the  first  tooth.  After  the  first 
tooth  has  been  moved  far  enough  mesially  or  distally,  the  next  adjoining 
tooth  is  moved  toward  it  in  the  same  manner,  and  so  on  until  all  of  the 
anterior  teeth  have  been  consecutively  and  bodily  moved. 


OPERATIVE   TECHNIC. 


733 


Treatment  of  Infra-Occlusion  of  Incisors  with  Sectional  Arch. 

— By  giving  a  slight  bend  occlusally  in  the  middle  section  of  the  arch 
wire  distal  to  the  cuspids,  the  pms  being  locked  in  the  tubes  on  all 
the  teeth  in  infra-occlusion,  force  is  exerted  in  the  line  of  the  long  axes 
of  the  incisors,  and  the  simpler  cases  of  infra-occlusion  may  be  cor- 
rected in  this  manner.  The  more  pronounced  cases  may  be  treated 
the  additional  use  of  intermaxillary  force  or  with  the  plain  arch. 

Adjustment  of  Sectional  Arch  for  Deciduous  Dentures. — In 
the  expansion  of  the  deciduous  dental  arch,  the  sectional  arch  is  adjusted 
after  a  method  illustrated  and  described  by  J.  L.  Young.  The  cuspid 
teeth  are  banded  and  provided  with  two  parallel  and  vertical  tubes  in 
which  are  fitted  correspondingly  located  pins  on  the  arch  wire,  Fig.  617. 


Fig.  618.     {Butler.) 

Thesedouble  locking  pins  and  tubes  lessen  the  liability  of  breaking 
the  pins  under  the  spring  pressure  from  the  straightening  out  of  the 
loops  which  are  arranged  as  shown  in  the  drawing,  one  mesial  and  one 
distal  to  each  cuspid. 

Auxiliary  Lock  Pins. — ^A  stronger  form  of  pin,  to  be  used  where 
there  is  a  very  great  strain  has  been  devised  by  Butler.  It  is  in  the 
form  of  a  latchpin  as  shown  in  Fig.  618.  This  form  of  pin  may  be  used 
on  the  molar  anchor  band  when  intermaxillary  anchorage  is  to  be  used, 
or  on  the  cuspids  in  expansion  of  the  deciduous  arch,  or  on  any  other 
ofhhe  teeth  where  unusual  strain  is  to  be  exerted.  These  pins  are  made 
with  pliers,  by  winding  .22-inch  gold  and  platinum  wire  around  the 
beaks  of  a  pair  of  pliers  with  the  ends  fashioned  as  in  Fig.  618,  in 
steps,  which  are  of  different  lengths  for  different  lengths  of  tubes. 


734  ORTHODONTIA. 

PART  VII. 
TREATMENT. 

General  Considerations. — ^The  conditions  involved  in  individual 
malocclusions  must  of  necessity  be  considered  in  the  same  general 
way  as  are  diseases  or  deformities  of  other  parts  of  the  body. 

There  should  be  recorded  on  a  chart  the  history  of  the  case  in  some- 
what similar  manner  to  that  in  vogue  in  general  medicine.  The  form  of 
chart  in  use  by  the  author  allows  of  a  record  of  the  age,  health,  and 
habits  of  the  patient,  the  possible  etiological  factors  involved,  such  as  the 
effects  of  childhood  diseases,  measles,  whooping-cough,  diphtheria ,  symp- 
toms of  rachitis,  the  conditions  of  the  naso-pharynx,  noting  the  presence 
of  adenoids,  enlarged  tonsils,  deflected  septi,  or  enlarged  turbinates. 
Also  the  association  of  visual  or  aural  defects  should  be  noted,  with  the 
possibility  of  their  having  the  same  general  cause  as  the  malocclusion. 
A  study  of  the  various  facts  brought  out  in  a  chart  diagnosis  of  this 
kind  cannot  fail  to  be  of  great  value  in  prognosis  and  treatment.  In 
some  cases,  the  history  of  the  patient  is  of  such  a  nature  that  treatment 
of  the  malocclusion  alone  is  of  little  value,  in  others,  it  is  the  one 
necessary  thing  that  will  restore  the  normal  function  of  the  masticatory 
organs,  and  bring  beauty  to  a  face  marred  by  lines  of  inharmony. 
Again,  the  treatment  of  the  malocclusion  may  so  stimulate  the  develop 
ment  of  structures  and  sinuses  adjacent  to  the  dental  arches  that  better 
respiration  is  established,  and  better  nutrition  inaugurated  through  the 
established  function  of  mastication.  The  possibilities  of  benefit  to  the 
general  health  through  these  and  more  obscure  channels,  such  as  a  possi- 
ble stimulus  to  the  organs  of  internal  secretion  by  which  bodily  growth 
is  controlled,  are  worthy  of  considerations.  The  lack  of  development 
in  the  dental  arches  can  no  longer  be  considered  in  the  light  of  local 
etiology,  when  such  profound  symptoms  of  general  disturbance  of 
function,  of  nutrition,  metabolism  and  bodily  growth  are  found 
associated  with  many  of  the  cases  presenting  with  malocclusion. 

Some  of  the  cases  presenting  with  marked  symptoms  of  pathological 
conditions  in  the  nose  and  throat  are  apt  to  have  suffered  to  such  an 
extent  the  ill  effects  of  the  troubles  coincident  with  the  "vicious  cycle" 
in  which  adenoids,  mouth-breathing  and  malocclusion  are  in  evidence, 
that  restoration  of  normal  conditions  of  either  nose,  throat  or  dental 
arches  seems  an  impossibility.  In  other  cases,  however,  if  the  patho- 
logical symptoms  have  been  of  short  duration,  and  the  orthodontic 
treatment  instituted  during  a  period  of  general  bodily  growth,  the 


TREATMENT.  735 

benefits  of  dental  arch  expansion  and  stimulation  to  the  growth  of  the 
structures  of  the  maxilla  and  adjacent  regions  of  the  internal  naries 
have  been  very  marked. 

The  effects  of  habits  in  malocclusion  are  so  important  in  their 
relation  to  treatment,  that  unless  they  are  taken  cognizance  of,  failure  is 
apt  to  ensue.  For  example,  if  a  malocclusion  be  caused  by  thumb- 
sucking,  and  the  cause  of  the  malocclusion  be  not  prevented  during 
treatment  the  continuance  of  such  a  habit  will  cause  the  return  of 
the  malocclusion. 

Local  Considerations. — In  making  a  diagnosis  of  the  maloc- 
clusion, after  noting  the  class,  any  peculiar  features  of  malocclusion 
should  be  taken  cognizance  of,  such  as  the  prolonged  retention  of 
deciduous  teeth,  loss  of  permanent  teeth,  absence  of  germ  of  perma- 
nent teeth,  impacted  teeth,  and  supernumeraries.  The  X-ray  should 
be  brought  into  frequent  use  in  determining  the  shape  and  position  of 
the  roots  of  impacted  teeth,  and  supernumeraries. 

The  relation  of  arch  width  to  arch  length,  the  height  of  the  plate, 
and  underdevelopment  or  overdevelopment  of  bony  structures  should 
be  taken  cognizance  of.  The  depth  of  the  overbite,  and  conditions 
involving  supra-  or  infra-occlusion  should  be  carefully  noted  with  a 
view  to  their  effect  upon  the  articular  movements  of  the  mandible, 
and  the  possibility  of  restoration  of  natural  articular  as  well  as 
occlusal  function. 

Finally,  a  study  of  the  case  should  be  made  with  reference  to  the 
problems  of  dynamics  and  anchorage  involved,  and  treatment  should 
not  be  instituted  until  they  are  satisfactorily  solved. 

The  beneficient  results  of  treatment  should  follow  along  the  lines  of 
development  of  the  dental  arches,  improvement  in  occlusion  and  facial 
lines,  better  masticating  powers,  better  respiration,  and  better  general 
health. 

Early  Treatment  of  Arrested  Developmental  Conditions  in 
the  Arches. — Any  arrested  or  deficient  development  of  the  arches  of 
teeth  may  be  diagnosed  in  advance  of  the  permanent  dentition,  and 
should  be  stimulated  to  normal  growth  and  development  as  early 
as  the  age  of  the  patient  will  allow  of  the  wearing  of  delicate  appliances 
for  the  purpose. 

The  lack  of  mesial  and  distal  spacing  between  the  deciduous 
incisors  and  cuspids  at  about  five  or  six  years  of  age  is  a  very  certain 
indication  of  a  lack  of  anterior  development  sufficient  for  the  proper 
eruption  of  the  permanent  teeth  succeeding  them. 

The  upper  deciduous  arch  may  be  in  lingual  occlusion,  or  the 


736 


ORTHODONTIA. 


lower  arch  may  be  mesial  or  distal  to  its  normal  position,  or  there 
may  even  be  infra-  or  supra-occlusion  present  in  the  deciduous  teeth, 
all  of  these  conditions  being  readily  diagnosed. 

If  the  deciduous  arch  needs  widening,  it  is  better  to  perform  this 
operation  some  little  time  before  the  roots  of  the  deciduous  molars 
have  begun  to  absorb,  since  the  crowns  of  the  permanent  bicuspids 
are  enclosed  within  the  roots  of  the  deciduous  molars,  as  may  be  ob- 
served in  Fig.  619,  and  the  result  of  the  expansion  will  be  to  move 
the  crowns  of  these  permanent  teeth  as  well  as  the  deciduous  teeth 
and  surrounding  alveolar  tissues  into  a  larger  arc,  aflording  a  gentle 
stimulus  to  the  normal  development  of  the  entire  arch. 


Fig.  619 


If  treatment  is  delayed  until  just  before  the  time  for  shedding 
of  the  deciduous  first  molars,  the  roots  of  these  teeth,  being  almost 
absorbed,  can  afford  no  resistance  to  the  appliance  in  expansion,  and 
their  crowns  will  be  shed  before  any  expansion  can  be  accomplished  in 
this  region,  which  will  then  delay  the  development  of  the  arch  in  this 
region  until  the  permanent  bicuspids  are  fully  erupted,  there  being  no 
other  means  of  anchorage  in  the  meantime,  except  what  may  be  pos- 
sibly obtained  through  the  ligation  of  the  deciduous  cuspid,  which  many 
times  is  prematurely  shed. 

The  author  has  obtained  the  best  results  in  arch  development 
between  the  ages  of  six  and  eight  years,  and  in  some  cases  still  younger, 
especially  in  cases  of  mesial  or  distal  occlusion,  lingual  occlusion  of  the 


TREATMENT. 


737 


whole,  or  portions  of  the,  upper  dental  arch,  and  upper  protrusions  of 
Class  I. 

It  is  reasonable  to  suppose,  from  the  rapidity  of  development  of 
the  alveolar  process  during  the  primary  stages  of  eruption  of  the 
permanent  teeth,  that  the  movement  of  the  deciduous  teeth  some  little 
time  previous  to  the  period  when  absorption  of  the  roots  of  deciduous 
cuspids  and  molars  is  about  to  be  initiated,  conforms  most  nearly  to  a 
natural  and  physiological  process,  and  that  the  amount  of  absorption 
of  alveolar  process  in  advance  of  moving  teeth  is  comparatively  slight, 
the  change  in  these  structures  being  analogous  to  the  natural  develop- 
mental changes  which  would  occur  in  case  no  arrest  of  development 
had  been  observed. 


Fig,  620. 

Realizing  the  benefits  of  such  early  development  of  the  dental 
arches,  the  orthodontic  specialist  prefers  to  operate  upon  the  chil- 
dren in  whose  mouths  the  presence  of  firmly  implanted  deciduous  teeth 
offer  a  firm  resistance  for  the  development  of  the  dental  arch  in  advance 
of  the  eruption  of  the  majority  of  the  permanent  teeth. 

Fig.  620  illustrates  the  development  of  an  upper  dental  arch  in  a 
case  in  which  the  deciduous  molars  were  used  for  resistance  throughout 
the  treatment  and  the  restoration  of  the  proper  size  and  shape  of  the 
arches  at  this  age  conforms  more  nearly  to  a  physiological  process  or  a 
stimulation  to  normal  development,  rather  than  a  tearing  down  and 
rebuilding  process  to  which  such  treatment  is  analogous  at  a  mature  age. 

Early  treatment  in  a  case  of  this  kind  is  undertaken  at  a  time  when 
the  alveolar  processes  are  more  cartilaginous  in  character  than  later,  the 
teeth  being  thus  more  readily  moved  because  of  lessened  resistance  than 
when  the  cartilaginous  structures  are  fully  calcified. 

Again  the  function  of  the  dental  arches  being  restored  early  in  child 
47 


738 


ORTHODONTIA. 


life,  all  developmental  processes  in  relation  thereto,  such  as  the  growth  of 
the  dental  and  maxillary  arches  and  the  nasal  cavities,  and  the  con- 
formation of  the  muscles  of  mastication  and  expression,  will  have 
the  best  chance  for  normal  development,  and  the  attainment  of  har- 
mony in  the  profile  will  thus  become  a  possibility  through  such  normal 
relationships. 

Furthermore,  the  earlier  treatment  is  undertaken,  the  less  tendency 
exists  for  the  return  of  the  malocclusion,  and  the  less  the  need  of  reten- 
tion, as  age  only  increases  resistance  to  tooth  movement,  confirms  the 
deformity  in  its  relationship  by  long  and  improper  function  of  occlusion 
and  muscular  expression,  and  initiates  structural  changes  in  bony  and 
muscular  tissues  which  cannot  be  altered  by  treatment. 

PART    VIII. 

TREATMENT  OF  CLASS  I. 

Diagnosis. — Malocclusions  of  Class  I  (Angle),  are  recognized  by 
the  normal  mesio-distal  relationship  of  the  dental  arches,  usually  deter- 
mined by  noting  the  occlusal  relations  of  the  mesio-buccal  cusps  of  the 


Fig.  621. 


upper  first  permanent  molars  with  the  lower  first  permanent  molars, 
when  present  in  the  arches.  In  the  absence  of  one  or  more  of  these 
teeth,  the  occlusion  of  the  bicuspids  will  serve  to  denote  the  normal 
mesio-distal  relation  of  the  dental  arches.  When  a  tooth  is  impacted, 
the  closing  up  of  the  space  for  its  eruption  must  be  taken  into  account, 
and  the  occlusion  of  all  of  the  erupted  teeth  must  be  observed  as  the 


TREATMENT.  739 

cusp  relation  might  in  cases  of  this  kind  indicate  a  mesial  or  distal 
occlusion  either  of  a  molar  or  bicuspid,  and  confuse  the  diagnostician. 

The  contraction  of  an  upper  dental  arch  will  often  cause  the  cusps 
of  the  lower  first  permanent  molars  to  assume  a  slight  distal  position, 
which  become  normal  in  their  relation  on  a  very  little  expansion  of  the 
upper  dental  arch.  This  fact  should  also  be  taken  into  account,  so  that 
a  case  exhibiting  these  peculiarities  of  deficient  development  be  not  diag- 
nosed as  belonging  to  Class  II. 

Again,  if  the  facial  inharmony  be  taken  as  a  guide  without  observ- 
ing the  mesio-distal  relationship  of  the  dental  arches,  a  case  might  be 
thought  to  belong  to  Class  II,  because  it  exhibited  protruding  upper 
incisors  and  an  apparently  receding  chin,  when  an  examination  of  the 
occlusal  relations  in  the  molar  region  would  immediately  prove  it  to  be 
one  of  the  not  infrequent  cases  of  Class  I  having  only  the  facial  symp- 
toms of  Class  II. 

Likewise  cases  belonging  to  this  class  simulate  the  general  appear- 
ance in  malocclusion  and  in  the  facial  inharmony  the  characteristics  of 
Class  III  with  retruded  upper  incisors  and  an  apparent  protrusion  of  the 
lower  dental  arch  and  of  the  chin,  while  the  molar  teeth  on  each  lateral 
half  are  in  the  normal  mesio-distal  relation  of  Class  I. 

Another  complication  of  Class  I  is  the  variation  of  the  underbite 
from  the  normal  line  of  occlusion  to  the  "open  bite"  or  infra-occlusal 
positions,  or  to  that  in  which  the  underbite  is  very  deep,  the  lower  inci- 
sors often  pressing  into  the  gum  tissue  lingual  to  the  upper  incisors. 

The  infra-occlusion  may  be  in  the  incisor  region  or  extend  distally 
as  far  as  the  second  molar,  or  there  may  be  infra-occlusion  in  the  bicus- 
pid region  alone,  or  in  the  bicuspid  and  molar  region  and  not  in  the 
incisor  region. 

The  variations  in  occlusal  and  facial  inharmony  are  more  varied  in 
Class  I  than  in  any  other  class,  and  these  factors,  together  with  the  mul- 
tiplicity of  malpositions  of  the  teeth,  and  the  simulations  in  general 
appearance  of  the  malocclusion  of  Class  II  and  Class  III,  make  the 
class  under  consideration  the  most  misleading  in  its  characteristics  and 
difficult  in  its  diagnosis. 

Relative  to  the  multiplicity  of  malpositions  of  individual  teeth,  in 
Class  I,  one  or  more  teeth  may  be  in  buccal  or  lingual  occlusion,  or  in 
supra  or  «w/ra-occlusion,  or  in  /or^o-occlusion,  characteristics  belonging, 
however,  to  any  of  the  classes  of  malocclusion. 

Among  the  local  etiological  characteristics  noted  in  this  class,  as  well 
as  in  some  of  the  other  classes,  are  the  prolonged  retention  of  deciduous 
teeth,  the  premature  loss  of  deciduous  teeth,  loss  of  permanent  teeth,  the 


740 


ORTHODONTIA. 


Fig.  622. 


Fig.  623. 


TREATMENT   OF   CLASS    I.  74 1 

shortening  of  mesio-distal  diameters  of  permanent  teeth  through  the 
ravages  of  caries,  supernumerary  teeth,  abnormal  frenum  labium,  and 
the  habits  of  lip  or  cheek  biting,  thumb  or  tongue  sucking  and  mouth- 
breathing. 


Fig.  624. 

Symptoms  of  mouth-breathing  should  be  immediately  noted,  and  the 
case  referred  to  a  competent  rhinologist  for  examinationrof  the^nose  and 
throat  and  removal  of  nasal  or  pharyngeal  obstructions  if  present. 


Fig.  625. 

Other  habits  such  as  sucking  the  thumb  or  tongue,  and  biting  the 
cheeks  and  lips,  should  be  combated  from  the  beginning  of  treatment,  or 
their  continuance  will  disarrange  whatever  perfection  of  occlusal  rela- 
tions that  might  be  attained  as  a  result  of  treatment. 


742  ORTHODONTIA. 

Extraction,  as  a  beneficial  procedure,  should  be  excluded  except 
in  rare  cases,  and  usually  where  it  has  already  been  resorted  to,  the 
restoration  of  space  which  has  been  lost  by  contraction  in  the  region  of 
extraction,  should  be  accomplished  and  the  space  retained  by  proper 
methods. 

The  diagnosis  of  this  Class  being  indicated  by  the  normal  mesio- 
distal  relation  of  the  dental  arches,  the  treatment  indicated  should 
be  along  the  lines  of  dental  arch  development  according  to  the  indica- 
tions for  that  treatment  previously  described. 

To  follow  a  consistent  sequence  in  describing  the  treatment  of  cases 
belonging  to  Class  I,  those  cases,  which,  on  account  of  their  youth,  and 
the  greater  possibilities  therefore  of  the  fullest  development  of  dental 
arches,  will  be  first  described,  and  next  thereafter  in  order  the  cases  of 
more  mature  years  in  which  the  lesser  development  of  dental  arches  is 
possible. 

Treatment  of  Special  Cases.  Case  I. — ^Although  the  malocclu- 
sions of  Class  I  present  varied  occlusions  of  the  anterior  teeth  from  supra- 
to  infra-occlusion,  there  is  a  common  type  of  malocclusion  in  which  the 
overbite  is  normal,  and  the  anterior  malocclusion  simply  one  of  lack  of 
development  exhibited  by  lack  of  sufficient  space  for  erupting  incisors. 

A  case  of  this  character,  age  nine  years,  is  shown  in  the  occluded 
casts  in  Fig.  621.  As  is  usual  in  such  cases  both  the  upper  and  the  lower 
dental  arches  are  deficient  in  their  growth,  and  the  indicated  treatment 
is  a  gentle  mechanical  stimulation  to  normal  development  by  means  of 
the  application  of  either  the  plain  or  sectional  expansion  arches. 

An  examination  of  the  upper  dental  arch,  Fig.  622  shows  that  the 
deciduous  cuspids  and  molars  are  still  intact  and  firm  in  their  positions, 
and  capable  of  offering  sufficient  resistance  to  the  appliance  for  lateral 
expansion  and  of  carrying  laterally  with  them  the  crowns  of  the  per- 
manent bicuspids  enclosed  by  the  roots  of  these  deciduous  teeth.  • 

Although  the  permanent  central  incisors  and  first  molars  have 
erupted,  as  far  as  development  is  concerned,  it  is  still  a  partially  decidu- 
ous dental  arch,  and  the  diagram  for  a  .39  central  incisor  indicates 
that  considerable  anterior  and  some  posterior  expansion  is  necessary  in 
order  to  secure  sufficient  development  of  the  arch  for  the  accommodation 
of  the  permanent  teeth  yet  to  erupt. 

The  result  of  treatment  of  this  upper  arch,  according  to  these  indica- 
tions, is  shown  in  Fig.  623  in  which  the  after-treatment  arch  conforms  to 
the  .39  diagram  which  predetermined  to  a  nice  degree  the  extent  of 
development  necessary. 

Fig.  624  exhibits  the  appliances  used  for  treatment  of  the  upper 


TREATMENT   OF    CLASS   I.  743 

dental  arch.  Plain  bands  with  lingual  wire  extensions  and  round 
buccal  tubes  were  used  for  the  anchorage,  and  a  17-gauge  expansion 
arch  for  the  force  appliance.  Lateral  expansion  was  secured  by 
ligating  the  lingual  wire  extensions  to  the  expansion  arch  after  placing 
it  in  position  with  a  medium  amount  of  lateral  spring.     Spurs  were 


Fig.  626. 


placed  on  the  arch  to  direct  the  deciduous  cuspids  distally  and  regain 
space  for  the  unerupted  laterals. 

A  similar  arrangement  of  the  expansion  arch  and  lingual  wire 
extensions  was  used  for  the  development  of  the  lower  dental  arch. 


Fig.  627, 

The  retention  of  the  upper  arch  of  this  case  is  illustrated  in  Fig.  727, 
the  deciduous  teeth  being  utilized  for  resistance  until  such  time  as  the 
absorption  of  their  roots  will  render  them  unfit  for  such  use.  The  width 
of  the  arch  is  retained  by  the  lingual  retaining  wire,  soldered  to  the  bands 
upon  the  deciduous  cuspids  and  molars,  and  the  central  incisors  are  held 


744  ORTHODONTIA. 

firmly  in  approximation. by  bands  soldered  together  and  cemented  in 
position. 

The  treatment  of  the  lower  arch  was  very  similar  to  that  of  the  upper, 
and  the  increased  development  obtained  was  retained  by  a  lingual  wire 
soldered  to  molar  bands. 

The  after-treatment  model  of  this  case,  Fig.  625,  represents  the  ex- 


FlG.  628. 

treme  of  dental  arch  development  in  a  case  in  which  the  facial  lines 
showed  no  particular  indications  of  undeveloped  dental  arches. 

Case  II. — Fig.  626  represents  the  right  side  in  occlusion,  before  and 
after  treatment,  of  an  average  case  of  Class  I,  the  arches  being  con- 
tracted and  the  teeth  anterior  to  the  first  molars  in  various  positions  of 


Fig.  629. 

malocclusion  previous  to  treatment.  After  treatment  the  teeth  are  in 
normal  occlusal  relations  as  noted  in  the  model  on  the  right  of  this 
'figure. 

The  left  side  in  occlusion,  in  Fig.  627,  illustrates  the  corrected  posi- 
tion of  the  upper  left  central  from  lingual  to  normal  occlusion,  and  the 
regaining  of  the  proper  space  for,  and  eruption  to  normal  position  of, 


TREATMENT    OF    CLASS    I.  745 

the  left  lower  second  bicuspid.  Fig.  628  exhibits  the  restoration  of 
the  normal  size  and  shape  of  the  upper  arch,  the  malposed  teeth 
being  placed  in  the  line  of  occlusion,  as  noted  in  the  cast  on  the  right 
of  the  cut. 

Fig.  629  presents  the  chief  difficulties  encountered  in  the  case, 
in  the  extent  of  the  contraction  of  the  anterior  portion  of  the  lower 
arch,  and  the  attainment  of  the  ideal  in  the  size  and  shape  of  the  arch 
as  a  final  result.  The  lower  unerupted  bicuspid  very  quickly  took 
advantage  of  its  release  from  imprisonment  between  the  first  bi- 
cuspid and  first  molar,  and  erupted  into  occlusion  without  mechanical 
aid,  lending  its  additional  support  as  a  keystone  to  hold  the  arch  intact. 
The  presence  of  the  unerupted  bicuspid  in  the  process  could  be  diag- 
nosed by  the  protuberance  of  the  gum  tissue  overlying  the  tooth, 
without  the  use  of  the  X-ray  diagnosis  often  necessary  in  these  cases. 

The  appliances  used  in  this  case  were  the  expansion  arch  and 
anchor  clamp  bands.  In  the  upper  arch,  the  left  central  was  banded, 
and  a  ligature  extended  from  a  lingual  spur  to  the  arch,  with  a 
rubber  wedge  between  the  mesial  angle  of  the  tooth  and  the  arch  to 
assist  in  its  rotation.  Very  little  expansion  was  needed  in  the  upper 
arch  beyond  that  necessary  for  the  accommodation  of  the  left  central, 
and  the  harmonizing  in  size  of  the  upper  with  the  lower  arch. 

In  the  lower  arch  considerable  lateral  expansion  was  necessary,  and 
the  appliances  were  adjusted  so  as  to  obtain  reciprocal  anchorage 
from  one  side  of  the  arch  to  the  other  through  ligatures  on  the  expansion 
arch.  The  left  lower  first  bicuspid  was  banded,  and  a  ligature  extended 
from  a  mesio-lingual  lug  on  the  band  to  a  spur  on  the  arch  wire,  so  as  to 
secure  the  two  necessary  movements  of  rotation  and  lateral  re-alignment 
of  this  tooth. 

The  case  just  illustrated,  although  presenting  some  difficulties  in  the 
treatment  of  the  lower  arch,  is  simple  compared  with  the  problems  of 
normal  arch  and  occlusal  restoration  exhibited  in  the  treatment  of  the 
next  case,  the  right  occlusion,  before  and  after  treatment  of  w^hich  is 
shown  in  Fig.  630. 

Case  III. — The  case  is  that  of  a  boy  fourteen  years  of  age,  and  in  the 
model  on  the  left  of  Fig.  630  may  be  noted  the  contracted  arch,  and  the 
closing  up  of  the  space  for  the  upper  second  bicuspid  and  the  partial 
closure  of  the  space  for  the  lower  bicuspids,  which  are  impacted  in  the 
alveolus  just  external  to  their  positions  in  the  arch. 

The  etiological  factors  in  this  case  were  obscure,  in  that  the 
boy  was  a  normal  breather,  of  good  history,  and,  beyond  the  pre- 
mature loss  of  the  deciduous  cuspids  and  molars    as  a  mechanical 


746 


ORTHODONTIA. 


factor  in  the  causation  of  the  undeveloped  arches,  very  little  could  be 
learned  of  a  pathological  nature  which  might  have  affected  the  nor- 
mal development  of  the  dental  arches. 


Fig.  630 


Fig.  631. 

The  occlusal  view  of  the  upper  casts,  before  and  after  treatment, 
in  Fig.  631,  exhibits  a  degree  of  expansion  which  would  not  have  been 
believed  possible  by  the  uninitiated  in  the  secrets  of  occlusal  restoration. 
The  upper  second  bicuspid  on  the  right  side  was  freed  from  impaction, 


TREATMENT    OF    CLASS    I. 


747 


and  erupted  to  its  proper  position  of  occlusion,  the  cuspids  also  being 
restored  to  alignment,  or  rather  the  rest  of  the  teeth  in  the  anterior 
part  of  the  arch  changed  to  the  cuspid  alignment,  as  the  cuspids  were 


Fig.  632. 


Fig.  633. 

more  nearly  in  their  normal  positions  than  any  of  the  other  anterior 
teeth. 

The  lower  cast  on  the  left  of  Fig.  632  exhibits  the  impaction  of 


748 


ORTHODONTIA. 


three  teeth,  two  bicuspids  on  the  right  side  and  the  second  bicuspid 
on  the  left  side,  the  release  of  which  could  never  have  been  possible 
without  the  interference  of  the  orthodontist.  In  the  cast  on  the  right, 
the  successful  accomplishment  of  the  necessary  expansion  for  the 
accommodation  of  these  teeth  in  the  arch  may  be  noted.  By  com- 
parison of  the  before  and  after  casts  of  both  upper  and  lower  arches 

in  this  case,  the  unusual  amount  of 
lateral  expansion  may  be  observed, 
showing  how  far  short  Nature  came 
in  her  development  of  the  arches,  and 
indicating  the  possibilities  of  applied 
science  in  the  restoration  of  the  normal 
in  development  and  the  ideal  in  occlu- 
sion and  harmony  of  contour  of  the 
arches  of  teeth. 

The  picture  of  the  left  occlusion 
of  the  case  before  and  after  treatment, 
in  Fig.  633,  needs  no  description. 
The  result  of  ideally  correct  treatment 
without  extraction  is  very  evident,  and 
the  classic  lines  in  the  after-treatment 
model  can  scarcely  be  excelled  in 
beauty  by  any  masterpiece  of  the 
sculptor's  art.  Notice  the  graceful  curves  of  the  arches,  the  symmetry 
and  proportion  of  contour,  the  wonderful  harmony  which  prevails  in 
the  arches  through  the  perfect  adjustment  of  each  occlusal  inclined 
plane  of  the  antagonizing  teeth  to  the  requirements  of  normal  occlusion. 
The  accompanying  profile  of  this  patient  in  Fig.  634  is  shown  to 
illustrate  the  fact  that  such  an  extensive  operation  of  expansion  of  the 
dental  arches  does  not  produce  undue  protrusion  of  the  upper  and 
lower  lips.  The  lower  part  of  the  face  is  entirely  in  harmony  with  the 
rest  of  the  features,  being  proportionate  for  its  type,  and  in  its  contour 
hardly  suggestive  that  an  operation  of  this  extent  had  been  performed 
upon  the  dental  arches. 

The  appliances    used   in  this  case  were  similar  to  those  in  the 
previous  case,  and  the  treatment  differed  only  in  the  extent  of  expan- 
sion carried  out,  and  the   opening  of  the  greater  number  of  spaces 
necessary  for  the  accommodation  of  the  teeth  which  were  either  par 
tially  or  wholly  unerupted. 

Soldered  spurs  upon  the  arches  guided  the  direction  of  the  ligatures 
upon  teeth  contiguous  to  the  spaces  to  be  opened,  some  of   which 


Fig   634. 


TREATMENT   OF    CLASS   I. 


749 


teeth  it  was  necessary  to  band,  and  provide  with  lingual  spurs  for  the 
most  positive  action  of  the  appliance  to  be  exerted  upon  them. 

In  the  upper  arch,  the  lateral  incisors  and  right  first  bicuspid  were 
banded  and  ligated  to  the  expansion  arch  from  spurs  attached  to  their 
disto-lingual  angles. 

In  the  lower  arch,  the  teeth  needing  banding  in  a  similar  manner 
were  the  right  cuspid  and  the  left  first  bicuspid,  as  a  most  positive 
attachment  of  ligatures  was  necessary  in  order  to  reopen  the  adjacent 
spaces  for  the  unerupted  teeth. 

Case  IV. — ^A  very  interesting  case  of  Class  I  in  the  peculiarity  of  its 
malocclusion,  and  in  the  combination  of  appliances  and  anchorage  nec- 


FiG.  635. 


essary  for  its  treatment,  is  illustrated  from  the  occlusal  aspect  of  the 
upper  arch  before  treatment  in  Fig.  635,  the  feature  of  particular 
interest  being  the  disto-lingual  position  of  the  upper  right  cuspid, 
which,  on  account  of  its  extreme  distal  position  opposite  the  lingual 
embrasure  between  the  two  bicuspids,  is  apparently  secure  in  its 
malocclusion,  presenting  unusual  obstacles  to  its  restoration  to  the 
line  of  occlusion. 

By  a  careful  conservation  of  anchorage  and  operation  of  the 
appliances,  the  accomplishment  of  the  desired  result  was  secured,  as 
shown  in  the  after-treatment  cast  of  the  upper  arch  in  Fig.  636. 


750 


ORTHODONTIA. 


Fig.  636. 


Fig.  637. 


TREATMENT    OE    CLASS    I. 


751 


The  primary  anchorage  and  its  usual  re-enforcements  by  ligatures 
for  expansion  of  the  arch,  is  entirely  inadequate  to  produce  the  desired 
results  in  a  case  of  this  kind,  for  although  the  space  for  the  right  cuspid 
could  be  regained  by  a  proper  direction  of  ligatures  on  the  expansion 
arch,  the  control  of  the  cuspid  in  lingual  occlusion  in  this  same  manner 
is  impracticable. 


Fig.  638. 

The  cuspid  needed  first  to  be  moved  forward  opposite  its  regained 
space  by  means  of  a  traction  screw  operating  from  the  first  molar 
anchorage,  being  attached  to  the  lingual  screw,  as  seen  in  Fig.  637, 
the  right  angled  end  operating  in  a  horizontal  tube  soldered  to  the 
mesial  surface  of  a  band  upon  the  cuspid. 


752 


ORTHODONTIA. 


Fig.  639. 


Pig.  640. 


TREATMENT    OF    CLASS    I. 


753 


The  expansion  arch  was  in  operation  at  the  same  time  enlarging 
the  arch  and  making  room  for  the  cuspid,  the  incisors  being  directed 
toward  the  opposite  side  of  the  arch  by  spurs  located  toward  the  left 
side  of  the  arch  from  each  incisor,  and  the  right  lateral  having  a  band 
with  a  lingual  spur  for  more  positive  action  of  the  ligature  at  this  point. 

It  is  evident  that  the  combined  distally  reacting  forces  of  the  ex- 
pansion arch  on  the  buccal,  and  the  traction  screw  on  the  lingual  side 
of  the  first  molar,  would  be  greater  than  the  resistance  of  the  first 
molar  without  re-enforcement,  and  the  use  of  intermaxillary  anchorage 
for  this  purpose  as  illustrated  in  Fig.  638  effectually  counterbalanced 
the  tendency  to  distal  movement  of  the  molar,  so  that  the  forces  acting 
mesially  from  this  base  could  operate  without  disturbing  the  stability 
of  the  anchorage. 


Fig.  641. 


Fig.  642. 


The  operation  on  the  lower  arch  was  comparatively  simple,  re- 
quiring lateral  and  anterior  expansion  to  harmonize  the  occlusion  with 
that  of  the  upper  arch,  at  the  same  time  regaining  the  full  space  for 
the  lower  right  first  molar,  part  of  the  mesio-distal  diameter  of  which 
had  been  lost  through  caries. 

The  success  of  this  combination  of  appliances  may  be  noted  in  the 
right  occlusion,  before  and  after  treatment,  in  Figs.  639  and  640,  the 
cuspid  occupying  its  normal  position  in  the  arch,  and  the  occlusion 
of  both  arches  being  restored  to  harmonious  cusp  relationship. 

Case  V. — Simulations  of  Class  II. — An  upper  protrusion  of  Class 
I  simulating  Class  II  is  illustrated  in  Figs.  641  and  642  before  and  after 
treatment. 

In  addition  to  the  protrusion  of  the  upper  incisors,  the  lower  arch 
was  contracted  in  the  region  of  the  second  bicuspid  which  was  une- 
48 


754  ORTHODONTIA. 

rupted,  and  its  space  in  the  arch  considerably  diminished  on  account 
of  the  early  loss  of  the  second  deciduous  molar. 

The  use  of  the  expansion  arches  for  treatment  of  this  case  was  very 
similar  to  its  application  in  Class  II  with  the  intermaxillary  elastics 


stretched  from  the  distal  end  of  the  buccal  tubes  on  the  lower  molar 
bands  to  the  hooks  on  the  upper  expansion  arch  are  illustrated  in  the 
drawing  in  Fig.  643. 

The  resistance  of  the  entire  lower  arch  was  enlisted  by  ligating  all 


Fig.  644.  Fig.  645. 

of  the  eight  anterior  teeth  to  the  lower  expansion  arch,  allowing  the 
nuts  to  be  tightened  occasionally  for  enlarging  the  lower  arch  and 
regaining  the  space  for  the  unerupted  second  bicuspid. 

By  allowing  the  expansion  arch  to  slide  distally  in  the  anchor  tubes 
on  the  upper  molar  bands,  all  of  the  intermaxillary  force  was  directed 


TREATMENT   OF   CLASS   I.  755 

against  the  labial  surface  of  the  incisors,  and  the  normal  occlusion  of  the 
anterior  teeth  restored. 

The  patient  had  been  a  mouth-breather  in  early  childhood,  but  had 
been  operated  upon  for  the  removal  of  adenoids  early  enough  so  that ' 
through  the  restoration  of  the  normal  in  occlusal  relations  of  the  arches 
of  teeth,  the  asymmetry  of  the  facial  lines  was  completely  overcome, 
as  is  evidenced  from  the  photographs  of  the  profile  in  Figs.  644  and 
645.  The  asymmetry  of  the  facial  lines  in  this  case  is  so  similar  to 
the  most  severe  types  of  the  first  division  of  Class  II,  that  a  differential 
diagnosis  cannot  be  made  without  a  diagnosis  of  the  cusp  relationship 
of  the  arches  of  teeth  in  occlusion. 

Variations  in  the  Overbite. — ^The  occlusion  of  the  upper  with  the 
lower  incisors  in  Class  I  has  a  wide  range  of  variance  from  the  "end 


Fig.  646. 

to  end  bite"  to  the  lapping  of  the  upper  over  the  lower  incisors 
so  as  to  completely  hide  the  latter  from  view  when  the  lips  are  parted 
and  the  teeth  closed.  Often  the  lower  incisors  are  elongated  and 
occluding  with  the  gums  lingual  to  the  upper  incisors.  This  condition 
is  usually  due  to  infra-occlusion  of  the  bicuspids,  or  molars,  sometimes 
to  a  supra-occlusion  of  the  incisors  at  the  same  time.  The  plane  of 
occlusion  of  the  upper  arch,  instead  of  being  convex  is  concave,  and  the 
treatment  for  this  condition  is  the  same  in  Classes  I  and  II.  One  method 
for  its  treatment  consists  in  the  wearing  of  a  bite  plate  for  opening  the 
bite  in  the  incisor  region,  while  the  triangular  use  of  the  intermaxillary 
elastics  as  in  Fig.  557  elevates  the  molars  into  occlusion.  This  method  of 
treatment  should  be  instituted,  if  possible,  before  the  eruption  of  the 
bicuspids  so  that  they  may  be  made  to  seek  the  new  plane  of  occlusion 
in  eruption,  and  thus  permanently  retain  the  established  occlusion. 
Another  method  of  treatment  of  this  condition  of  infra-occlusion. 


756 


ORTHODONTIA. 


which  is  applicable  only  after  the  eruption  of  the  bicuspids,  is  to  apply 
the  light  expansion  arch  as  a  double  elastic  lever  springing  it  downward 
over  hooks  on  upper  bicuspid  bands  and  under  hooks  on  upper  incisor 
'bands,  as  in  Fig.  608.  A  lingual  arch  attached  in  a  similar  manner 
can  be  used  for  retention. 

Case  VI. — Simulations  of  Class  III. — Fig.  646  illustrates  a  not 
uncommon  case  of  Class  I  in  which  the  characteristics  of  Class  III  are 
simulated  in  the  apparent  protrusion  of  the  lower  arch,  and  the  inhar- 
mony  of  the  facial  lines. 


Fig.  647. 


Fig.  648. 


In  the  treatment  of  this  case,  anterior  expansion  of  the  upper  arch 
alone  was  necessary,  with  bands  upon  the  lateral  incisors,  and  ligatures 
so  directed  and  manipulated  that  the  space  for  the  unerupted  cuspids 
was  regained,  after  which  a  lingual  retaining  plate  was  used  for  reten- 
tion, a  buccal  spur  extending  through  the  cuspid  spaces. 

In  many  of  these  cases  which  resemble  Class  III  in  the  anterior  mal- 
occlusion, however,  it  is  necessary  to  apply  intermaxillary  force  to  sus- 
tain the  upper  molar  anchorage.  The  lack  of  intermaxillary  develop- 
ment in  the  upper  arches  of  these  cases  is  so  marked  that  the  use  of  the 
sectional  arch  for  bodily  movement  of  the  incisors  is  advisable. 


TREATMENT    OF    CLASS    I. 


757 


The  profiles  of  this  patient,  before  and  after  treatment,  in  Figs.  647 
and  648,  show  the  result  of  the  treatment  in  restoring  harmony  to  the 
face,  and  contrast  the  error  of  diagnosis  from  the  facial  lines  alone,  as 
a  casual  observance  of  the  profile  alone  would  indicate  a  protrusion  of 
the  lower  arch  characteristic  of  Class  III. 


Fig.  649.     (Lourie.) 

Case  VII. — Infra-occlusion  of  Incisors  and  Cuspids. — ^Lack  of 
occlusion  of  the  incisors  and  cuspids  and  often  of  the  bicuspids  is  a 
condition  not  uncommonly  found,  usually  in  mouth-breathers,  and 
varying  in  extent  somewhat  according  to  the  aggravation  of  the  habit. 
It  occurs  in  all  classes  of  malocclusion,  and  because  of  the  less  number 


Fig.  650. 

of  complications  it  presents  in  Class  I,  it  responds  more  readily  to 
treatment  than  in  the  other  classes. 

As  this  condition  is  essentially  a  lack  of  development  of  the  pre- 
maxillary  portion  of  the  arches,  and  an  abnormal  development,  in  many 
cases,  of  the  posterior  part  of  the  arches,  cases  presenting  infra-occlusion 


758  ORTHODONTIA. 

of  the  anterior  teeth  should  be  treated  as  early  as  possible,  and  especially 
normal  habits  of  breathing  should  be  restored  at  the  same  time  so  that 
development  may  be  further  unimpeded  by  any  nasal  or  other  respira- 
tory obstruction. 

Fig.  649  illustrates  a  case  of  infra-occlusion  of  this  class,  the  after- 
treatment  model  representing  as  near  the  ideal  in  treatment  of  these 
conditions  as  it  is  possible  to  attain. 

In  the  treatment  of  a  case  of  this  character,  intermaxillary  an- 
chorage should  be  established  between  the  anterior  parts  of  the  upper 
and  lower  arches,  and  the  expansion  arches  adjusted  over  spurred 
bands  with  the  intermaxillary  elastics  extending  from  hooks  on  the 
lower  expansion  arch  to  hooks  on  the  upper  expansion  arch,  as  shown 
in  Fig.  650.  It  is  advisable,  of  course,  to  first  obtain  the  normal  shape 
and  size  of  each  dental  arch  before  applying  the  intermaxillary  force. 
The  elastics  should  be  worn  as  continuously  as  possible  and  should 
be  adjusted  so  as  to  operate  very  slowly  in  order  not  to  move  the 
teeth  out  of  their  sockets  in  advance  of  the  developing  downwards  or 
upwards  of  the  maxillary  processes. 

It  is  possible  to  treat  the  simpler  cases  of  infra-occlusion  of  the 
anterior  teeth  of  Class  I  without  the  use  of  individual  bands  upon  the 
teeth,  the  wire  or  silk  ligatures  around  the  incisors  and  cuspids  and 
other  teeth  sufficing  to  move  these  teeth  as  desired.  However,  cases  of 
any  difficulty  respond  much  more  quickly  when  the  individual  teeth  are 
banded,  with  spurs  extending  from  the  bands  over  the  expansion  arch. 

The  same  result  may  be  obtained  in  the  use  of  the  sectional  arch 
by  bending  the  lateral  loops  to  cause  downward  pressure  on  the  vertical 
pins  in  the  incisor  tubes  as  suggested  by  J.  L.  Young. 

After  the  age  of  development  has  passed,  the  difficulties  attendant 
upon  retaining  the  teeth  in  occlusion,  even  though  the  operation  might 
be  otherwise  possible  and  feasible,  render  it  advisable  in  many  cases 
to  perform  the  simpler  operation  of  extensive  grinding  of  the  molars 
and  bicuspids  until  occlusion  is  obtained,  even  if  the  vitality  of  one  or 
more  of  the  molars  be  sacrificed  in  so  doing. 

The  author  has  obtained  good  results  from  this  procedure  in  adult 
cases,  observing,  however,  great  care  that  a  certain  amount  of  cusp 
articulation  is  preserved  in  order  that  the  functions  of  articulation  and 
mastication  may  not  be  interfered  with.  In  other  words,  the  molars 
should  not  be  ground  off  flat,  but  grooved  for  cusps  as  in  grinding 
artificial  teeth  for  articulation.  The  operation  is  a  difficult  one,  in 
that  it  requires  the  greatest  care  not  to  grind  too  much  upon  certain 
teeth  and  not  enough  upon  others.     Occlusal  contact  points  should  be 


TREATMENT   OF    CLASS   I. 


759 


ground  a  little  at  a  time,  on  one  side  of  the  arch  and  then  upon  the  other, 
approximating  the  arches  of  teeth  only  a  limited  amount  at  each  of 
several  sittings  until  occlusion  is  obtained. 

The  shortness  of  the  lips,  especially  the  upper  Hp,  in  most  of  these 
cases  is  such  as  to  preclude  the  idea  of  elongation  of  the  incisors  to 
occlusion,  an  unnatural  length  being  unesthetic. 

Infra-occlusion  of  Anterior  Teeth  Involving  Change  of  Angle 
of  Mandible. — In  the  severest  cases  of  infra-occlusion  of  the  anterior 
teeth,  including  the  bicuspids  and  first  molars  the  facial  lines  are  very 
much  disfigured,  the  angle  of  the  mandible  being  apparently  bent  down- 
ward very  obtusely,  and  the  naso-mental  distance  greater  than  normal. 

This  condition,  described  by  Carabelli 
as  "Mordex  apertus,"  is  more  of  a  de- 
formity of  the  mandible  than  of  the  teeth 
■  and  their  processes,  but  is  found  in  the 
three  main  classes  as  noted  by  the 
mesio-distal  relationship  of  the  denta 
arches,  and  until  a  simpler  classification 
of  these  mandibular  deformities  is 
found,  it  would  seem  reasonable  to  in- 
clude them  in  the  "  three-class  scheme  " 
of  Angle's  classification,  where  their  in- 
dividual peculiarities  may  be  described, 
and  special  treatment  indicated. 

The  causative  factors,  while  very 
obscure,  seem  to  be  involved  with 
mouth  breathing,  and  abnormal  work- 
ing of  masticatory  muscles,  and  with 
the  diseases  of  childhood,  especially 
rachitis  (Lind).  It  would  appear  to  the  author  that  this  condition  is 
largely  one  of  faulty  respiration,  which  induces  wrong  muscular  action 
upon  the  mandible,  which  becomes  deformed  as  a  result  of  the  abnormal 
action  of  these  muscles  upon  its  surface,  the  form  and  structure  of  the 
bone  being  an  expression  of  bone  function.  Some  of  these  cases  seem  to 
have  rachitic  tendencies,  others  not. 

The  treatment  of  advanced  cases  of  this  type  is  not  attended  with  any 

degree  of  success,  but  if  undertaken  when  the  cases  are  incipient,  in  the 

early  stages  of  childhood,  good  results  may  be  obtained  by  the  use  of 

headgear  and  chin  cap  such  as  has  been  described  by  Law  and  Lind.* 

Fig.  651  illustrates  the  Lind  headgear  and  chin  cap.     By  the  use  of 

*  Transactions  European  Orthodontia  Society;  19 13. 


Fig.  651. 


760 


ORTHODONTIA. 


Fig   652     (Kern pie  ). 


Fig.  653. 


TREATMENT   OF    CLASS   I. 


761 


this  apparatus  at  night  only  in  very  young  children  for  a  comparatively 
long  period,  the  anterior  teeth  may  be  brought  together  and  retained. 

The  Lind  apparatus  depends  upon  the  use  of  heavy  elastics  in  front 
of  the  face  from  headgear  to  chin  cap,  while  the  Law  apparatus  has  the 
heavy  elastics  adjusted  from  the  side  of  the  headgear  exerting  more  (of 
an  upward  and  backward  pull. 

Case  VIII. — Infra-occlusion  of  Molars  and  Bicuspids. — Figs. 
652  and  653  illustrate  a  Class  I  case  of  infra-occlusion  of  the  molars  and 
bicuspids.     This  condition  is  a  very  unusual  one,  presenting  as  it  does, 


Fig.  654, 

with  the  incisor  region  in  perfect  normal  occlusal  relations  and  an  entire 
lack  of  occlusion  from  the  cuspid  to  the  second  molar  on  each  side.  The 
patient  was  fifteen  years  of  age  and  the  function  of  mastication  was 
limited  to  the  six  anterior  teeth,  in  each  arch.  Such  peculiarities  of 
abnormal  development  are  hard  to  explain,  yet  the  fact  that  they  exist 
ought  to  bring  to  bear  a  much  closer  study  of  the  underlying  factors  in 
development  which  produced  them. 

In  the  treatment  of  this  case.  Fig.  654,  expansion  arches  were  ad- 
justed to  each  arch,  using  the  first  molars  as  a  primary  anchorage  for  the 
clamp  bands,  banding  the  eight  bicuspids,  with  spur  extensions  over  the 
expansion  arches  above  and  below.  The  incisors  and  cuspids  were 
allowed  to  remain  free  from  ligation,  as  they  were  not  to  share  in  the 
movements  to  be  undertaken. 


62 


ORTHODONTIA. 


Fig  655. 


Fig.  656. 


TREATMENT    OF    CLASS    I. 


763 


Intermaxillary  elastics  were  then  adjusted  between  spurs  on  the 
buccal  tubes  of  the  molar  clamp  bands  and  from  each  expansion  arch 
in  the  region  of  the  first  bicuspids. 

The  after-treatment  models  of  the  case  are  shown  in  Figs.  655  and 
656,  showing  the  molars  and  bicuspids  have  been  drawn  into  occlusion 
with  each  other,  and  a  very  successful  result  obtained.  The  retention 
consisted  of  a  continuation  of  the  use  of  the  intermaxillary  force  in 


Fig.  657. 

connection  with  a  more  delicate  and  inconspicuous  appliance  for  an 
indefinite  period. 

Operation  for  Abnormal  Frenum  Labium. — The  separation 
of  the  upper  central  incisors  through  the  abnormal  lingual  attachment 
of  the  frenum  labium,  extending  between  the  teeth  to  the  lingual  tuft  in 
some  cases,  usually  requires  the  bodily  movement  of  the  two  teeth 
together,  and  their  retention  for  a  considerable  period,  until  the  frenum 
assumes  a  higher  position  in  its  growth. 

The  present  methods  of  treatment  of  these  cases  vary  considerably; 
in  one  case  the  frenum  is  partially  dissected  from  its  attachment  be- 


y64  ORTHODONTIA. 

tween  the  central  incisors,  by  making  incisions  upon  either  side  of  it, 
and  cutting  it  off  with  a  pair  of  gum  scissors  sHghtly  above  the  necks 
of  the  incisors,  cauterizing  the  incised  wound  with  the  electric  cautery ; 
in  another  case  the  operation  may  not  be  necessary  after  moving  the 
usually  diverging  roots  of  the  incisors  together  and  retaining  them 
during  a  sufficient  period  of  growth. 

In  either  case,  the  centrals  are  fitted  with  bands  having  the  vertical 
tubes  of  the  new  Angle  appliance  properly  placed  nearer  the  mesial 
angles  of  the  incisors,  and  the  bands  cemented  in  position.  If  the  cen- 
trals need  rotating,  the  tubes  may  be  located  nearer  the  distal  angles.  A 
case  of  abnormal  attachment  of  the  frenum  labium,  before  and 
after  treatment  by  incision  and  moving  the  incisors  together  is  shown 
in  Fig.  657. 


Fig.  658. 

A  portion  of  the  new  Angle  sectional  arch  wire,  .030  in.,  with  ver- 
tical pins  fitting  the  tubes  on  the  incisor  bands,  and  a  contractile  loop  in 
the  base  wire  between  the  centrals,  as  in  Fig.  658,  will  serve  to  move 
them  together,  and  act  as  a  retainer  as  well. 

The  movement  of  the  incisors  together  occupies  but  a  short  period 
of  time,  but  their  retention  is  a  matter  of  a  year's  time  even  in  the  young- 
est cases.  The  two  central  incisor  bands  are  usually  soldered  together 
and  cemented  in  position  for  the  retention  of  these  cases. 

It  is  not  necessary  to  perform  the  operation  of  frenum  resection 
in  every  case  presenting  with  separation  of  the  central  incisors.,  the 
simpler  and  sometimes  the  more  severe  cases  responding  to  the  treat- 
ment indicated  of  movement  of  the  incisors  together,  with  a  prolonga- 
tion, however,  of  the  period  of  retention. 


TREATMENT    OP    CLASS   II.  765 

PART  IX. 
TREATMENT  OF  CLASS  II. 

Diagnosis  of  Class  II. — The  distinguishing  characteristic  of  Class 
II  in  occlusal  relations,  is  the  bilateral  or  unilateral  distal  occlusion 
of  the  lower  arch,  the  upper  arch  being  narrow  with  protruding 
incisors  in  the  first  division,  and  retruded  incisors  in  the  second 
division. 

The  facial  profile  is  deficient  in  contour  in  such  a  way  as  to  be 
indicative  of  the  malocclusion,  the  chin  and  lower  lip  receding,  and 
the  upper  lip  protruding,  in  the  first  division  of  this  class,  as  illustrated 
in  Fig.  672.  In  the  second  division,  a  marked  recession  of  both  upper 
and  lower  lips  and  chin  is  noticeable,  as  in  Fig.  688. 

The  habit  of  mouth-breathing,  and  the  open  and  drooping  mouth, 


Fig.  659. 

the  short  upper  lip,  the  receding  chin  and  the  facial  expression,  are 
peculiarly  diagnostic  of  the  first  division  of  Class  II,  although  it  is 
sometimes  difficult  to  distinguish  it  from  the  mouth-breather  of  Class 
I  by  observance  of  the  facial  inharmony  alone. 

The  presence  of  adenoids  and  enlarged  tonsils  is  sufficient  evi- 
dence of  the  causative  factors  underlying  the  mouth-breathing,  which 
should  receive  early  operative  treatment  by  the  rhinologist. 

The  study  of  the  possible  etiology  of  the  particular  malocclusion 
manifested  in  Class  II  cases  is  important  to  the  diagnostician,  as  upon 
his  ability  to  recognize  the  chief  causative  factors  present  in  these  con- 
ditions rests  his  success  or  failure  in  their  treatment. 

Following  back  the  history  of  this  class  of  cases  to  a  period  when  cer- 
tain arrested  developmental  conditions  were  inaugurated,  it  may  be 
assumed  that,  consecutively,  arrest  of  development  first  occurred  in  one 
or  both  of  the  dental  arches,  and  secondly,  the  later  growth  of  the  dental 
arches  was  along  abnormal  lines  influenced  by  such  factors  as  malocclu- 


766  ORTHODONTIA. 

sion  of  the  inclined  cusp  planes,  and  in  many  cases  by  the  habit  of 
mouth-breathing,  with  its  abnormal  tension  of  muscles. 

In  a  careful  study  of  these  conditions,  the  author  believes  that 
there  is  a  predisposition  to  the  malformation  of  the  dental  arches  and 
the  distal  occlusion  in  these  cases  long  before  the  eruption  of  the 
permanent  teeth  to  occlusion. 

The  existence  of  distal  occlusion  of  the  deciduous  arches  establishes 
the  claim  that  certain  persistent  factors  other  than  any  cusp  influence 
must  have  been  pre-operative  in  causing  these  conditions  in  the  decidu- 


FlG.   660. 


ous  arches.  That  distal  occlusion  is  not  uncommon  among  children  of 
less  than  six  years  of  age  is  a  fact  which  the  model  collections  of  the 
specialist  in  orthodontia  can  easily  prove. 

Treatment  of  these  conditions  of  distal  occlusion  in  the  deciduous 
arches  is  established  upon  the  same  basis  of  restoration  of  normal 
occlusion  and  development  as  with  the  dental  arches  which  contain 
at  least  the  four  permanent  molars  of  the  second  dentition. 

Figs.  659  and  660  illustrate  the  distal  occlusion  and  facial  profile  of 
a  child  two  years  and  ten  months  old.  Not  only  is  the  distal  occlusion 
of  considerable  extent,  but  the  facial  inharmony  is  easily  noticeable  at 
this  age. 


TREATMENT    OF    CLASS    II.  767 

It  is  the  author's  opinion  that  the  large  majority  of  cases  of  distal 
occlusions  are  initiated  during  the  retention  of  the  deciduous  teeth, 
and  the  impress  of  arrested  function  and  growth  so  made  upon  the 
developing  structures  of  the  maxillae  that  none  but  artificial  stimulus 
can  again  restore  the  normal  in  developmental  conditions. 

It  is  possible  that  holding  the  mouth  open  in  mouth-breathing 
gives  the  mandible  its  distal  pose  in  these  cases,  and  it  is  certain  that 
in  those  cases  of  Class  II,  Div.  i,  having  the  [shortened  upper  lip, 
the  abnormal  tension  of  the  muscles  is  an  etiological  factor  in  the 
narrowifig  of  the  upper  arch,  which  latter  is,  of  itself,  an  effectual 
barrier  to  a  forward  pose  of  the  mandible. 

In  the  treatment  of  certain  cases  of  Class  II,  Div.  i,  it  has  been 
frequently  observed  that  after  a  sufficient  expansion  of  the  upper 
dental  arch,  especially  in  children  under  ten  years  of  age,  the  mandible 
moves  forward  of  its  own  volition  until  the  first  molars  are  in  correct 
mesio-distal  relations. 

Recognizing  the  possibility  of  arrested  or  deficient  development 
of  the  maxillary  arches  being  primarily  due  to  such  general  causes 
as  malnutrition,  or  defective  metabolism  of  a  peculiar  nature,  associated 
with  such  local  conditions  as  nasal  stenosis  and  mouth-breathing,  it  will 
be  admitted  that  the  time  the  interference  with  development  occurs  will 
bear  a  certain  definite  relation  to  the  period  of  deficiency  in  local  asso- 
ciated functions  of  the  oral  and  nasal  cavities  or  of  the  general  nutritive 
functions. 

Ottolengui  very  aptly  states  this  theory  in  the  following  manner: 
"Malnutrition  is  the  special  cause  of  malocclusions  of  Classes  II 
and  III.  The  permanent  teeth  do  not  displace  those  of  the  primary 
set,  but  erupt  into  a  larger,  and  what  is  more  important,  an  entirely 
different  arch,  and  the  bony  process  is  a  new  bone  built  about  them 
during  their  eruption.  Grant  this  hypothesis,  and  it  is  evident  at  once, 
that  if,  during  this  period  of  transformation,  there  be  an  interference 
with  normal  functions,  there  may  and  probably  will  be  a  lack  of  bone 
building  nutriment.  What  will  result?  The  permanent  teeth,  all 
larger  than  their  predecessors,  erupt  into  the  same  small  arch  which 
the  temporary  teeth  had  occupied,  or  into  one  insufficiently  enlarged, 
because  of  insufficient  nutritive  elements." 

"  Thus  the  consequent  malocclusion  oj  the  teeth  will  he  in  nature  and 
degree  constantly  related  to  the  extent  and  time  of  the  disturbance  in  nutri- 
tional functioning.^'* 

*  R.  Ottolengui,  "A  Contribution  to  the  Etiology  and  Treatment  of  Class  II"  Transac- 
tionb  of  the  American  Society  of  Orthodontists,  IQ07. 


768  ORTHODONTIA. 

If  this  lack  of  development  be  possibly  due  to  functional  insufficiency 
on  the  part  of  the  organs  of  internal  secretion,  the  time  of  the  initial 
arrest  of  developmental  conditions  may  extend  back  to  prenatal  or 
early  postnatal  life,  and  be  related  in  extent  to  the  degree  of  profound- 
ness or  persistence  of  the  initial  functional  disturbance. 

It  is  of  special  importance  that  the  treatment  of  Class  II  cases  should 
be  begun  at  an  early  age  in  order  to  take  advantage  of  a  normal  growth 
period  during  and  after  the  correction  of  the  malocclusion,  the  stimulation 
to  normal  development  through  treatment  assisting  materially  in  the  per- 
manent retention  of  the  normal  occlusal  relation.  Cases  may  be  begun 
before  the  eruption  of  the  first  permanent  molars,  but  the  author  has  had 
better  results  in  beginning  them  just  after  the  eruption  of  these  teeth. 

Examination  for  Mouth -breathing  and  Tongue  and  Lip  Habits. 
— ^Inasmuch  as  mouth-breathing  is  so  commonly  co-existent  with  distal 
occlusion,  its  diagnosis  in  any  case  should  be  followed  by  an  examination 
of  the  nasal  and  pharyngeal  passages  by  a  competent  rhinologist,  and 
the  removal  of  respiratory  obstruction  if  found.  Tongue  and  lip  habits 
should  be  noted  and  their  effects  counteracted  as  soon  as  possible. 

Technic  of  Operative  Treatment  in  Class  II,  Div.  I. — The 
operative  treatment  of  Class  II,  Div.  I,  may  be  divided  into  several  stages, 
the  restoration  of  normal  size  and  shape  of  the  dental  arches,  the 
shifting  of  the  occlusal  relations  from  distal  to  normal  mesio-distal 
relations,  and  changes  in  the  occlusal  plane  when  necessary  in  cases  of 
deep  overbite,  or  of  infra-occlusion  of  the  anterior  teeth. 

The  restoration  of  the  size  and  shape  of  the  dental  arches  is  secured 
by  the  application  of  the  expansion  arches  as  in  Class  I,  and  the  shifting 
of  the  occlusion  as  obtained  by  the  use  of  interrriaxillary  force  as  illus- 
trated in  Fig.  556. 

Normal  Overbite. — ^In  cases  presenting  with  a  short  overbite  of  the 
lower  incisors,  the  technic  differs  somewhat  from  that  of  cases  in  which 
the  overbite  is  deep.  In  the  cases  presenting  with  a  short  overbite  or  a 
normal  overlap  of  the  upper  incisors,  the  two  consecutive  steps  in  the 
treatment  consist  first,  in  the  development  or  expansion  of  the  den- 
tal arches,  and  second,  in  the  shifting  of  the  occlusion  from  distal  to 
normal. 

The  expansion  arches  are  adjusted  as  in  the  treatment  of  Class  I, 
except  that  the  upper  expansion  arch  is  provided  with  hooks  for  the 
attachment  of  intermaxillary  elastics.  On  account  of  the  not  infrequent 
breaking  of  the  upper  expansion  arches  through  the  pull  of  the  elastics, 
the  arch  should  be  of  a  larger  gauge  as  it  enters  the  buccal  tube  di- 
minishing in  diameter  in  the  anterior  arc,  if  it  is  desired. 


TREATMENT   OF   CLASS  U. 


769 


Intermaxillary  force  and  anchorage  is  secured  by  the  attachment  of 
the  rubbers  from  the  hooks  on  the  upper  expansion  arch  to  the  ends  of 
the  tubes  on  the  lower  expansion  arch,  as  illustrated  in  Fig.  661.  In 
simple  cases  of  this  class  the  first  permanent  molars  may  be  used  for 
attachment  of  anchor  bands  in  case  the  second  molars  are  erupted, 
since  the  intermaxillary  force  can  be  made  strong  enough  to  move 
the  upper  molars  distally  and  the  lower  molars  mesially. 

It  may  be  necessary  in  the  treatment  of  mixed  dentures  in  which 
there  is  much  anterior  expansion  needed  in  the  lower  dental  arch,  and  in 
which  the  second  premanent  molars  are  unerupted,  to  apply  intermax- 
illary force  at  first  as  a  re-enforcement  of  the  lower  molar  anchorage  and 
later  with  force  enough  to  shift  the  occlusion. 


YlG.  661. 

After  the  lower  arch  has  been  partially  shifted  the  lower 
expansion  arch'may  be  removed  and  a  lingual  arch  soldered  to  the  molar 
anchor  bands  which  are  provided  with  hooks  instead  of  the  buccal 
tubes.  The  lingual  arch  acts  as  a  retainer  and  the  lower  incisors  can 
be  more  easily  kept  clean  during  the  long  period  of  treatment. 

In  more  mature  cases  of  this  class,  in  which  the  bicuspids  and  second 
molars  are  present,  and  especially  cases  in  which  it  is  desired  to  move 
the  upper  molars  distally  to  any  extent,  the  anchor  bands  should  be 
placed  on  the  upper  second  molars  and  shifted  to  the  first  molars  as 
soon  as  the  desired  movement  of  the  second  molars  has  been  accom- 
plished. It  may  even  be  necessary  to  remove  the  anchor  bands  from 
the  upper  first  molars  and  place  anchor  bands  on  the  upper  second,  and 
even  first  bicuspids  in  succession  for  support  of  the  expansion  arch  and 
further  shifting  of  the  occlusion  in  the  bicuspid  region.  During  the  use 
of  intermaxillary  force  for  shifting  the  molar  occlusion,  the  front  of  the 
49 


770  ORTHODONTIA. 

upper  expansion  arch  should  be  kept  free  from  the  anterior  teeth  by 
tightening  up  the  nut  in  front  of  the  anchor  tubes  so  as  to  apply  the 
greatest  amount  of  distally  exerted  force  directly  to  the  molar  teeth. 

The  strength  of  the  intermaxillary  force  can  be  increased  by  using 
a  heavier  ligature  or  a  number  of  the  same  size,  cut  from  French  tubing. 

While  these  manipulations  of 
anchor  bands  and  expansion 
arches  are  being  carried  on  in 
the  upper  arch,  the  entire  lower 
arch  may  be  used  part  of  the 
time  as  resistance  for  the  shift- 
ing of  the  upper  molar  occlusion, 
by  the  ligation  of  a  sufficient 
number  of  teeth  to  the  lower  arch 
to  insure  its  stability. 

Again,  the  lower  incisors  may 
Pig  652.  be  ligated  to  the  expansion  arch 

and  moved  forward,  and  suc- 
cessively, also,  the  cuspids  and  the  bicuspids,  to  secure  direct  appli- 
cation of  the  force  from  the  turning  up  of  the  nuts  in  front  of  the 
lower  anchor  bands,  these  teeth,  in  turn,  being  moved  mesially  by  the 
intermaxillary  force. 

There  is  one  very  important  detail  in  the  manipulation  of  this 
anchorage  in  Class  II  and  III  cases  which  uught  to  be  described  in  this 
connection,  and  that  is  the  tipping  backward  of  the  upper  molars  in 
Class  II,  and  the  lower  molars  in  Class  III — and  the  tipping  forward 
of  the  lower  molars  in  Class  II,  and  the  upper  molars  in  Class  III — 
which  in  turn  shifts  the  expansion  arch  upward  or  downward,  as  the 
case  may  be. 

To  remedy  this,  and  keep  up  the  efficiency  of  the  anchorage,  the 
anchor  bands  should  be  removed  and  the  angle  of  the  incHnation  of  the 
tubes  changed  according  to  the  necessities  of  the  case  and  the  class. 
Fig.  780  A  exhibits  the  tipping  of  upper  molars  and  downward  inclina- 
tion of  the  expansion  arch  in  a  case  of  Class  II,  and  B  the  restoration  of 
the  arch  to  position  after  re-aligning  of  the  tube  on  molar  clamp  band. 
In  shifting  the  occlusion  from  distal  to  normal  in  some  cases  in 
which  the  permanent  teeth  are  nearly  all  erupted,  it  will  be  found  that 
although  the  molars  may  respond  readily  to  the  intermaxillary  force, 
the  cuspids  and  bicuspids,  especially  in  the  upper  arch,  may  not  be  so 
easily  moved  in  the  desired  directions  through  the  application  of  the 
elastics  from  the  hooks  upon  the  upper  expansion  arch  to  the  distal 


TREATMENT    OF    CLASS    II. 


771 


ends  of  tubes  on  lower  molar  clamp  bands.  In  these  cases,  Casto 
has  suggested  the  use  of  intermaxillary  elastics  between  individual 
banded  teeth  of  the  upper  and  lower  arch  to  overcome  the  difficulty,  as 
in  Fig,  661. 

Excessive  Overbite. — A  feature  of  no  small  importance  in  many 
cases  of  distal  occlusion  is  the  excessive  overbite  in  the  incisor  region, 
which,  if  not  overcome,  will  militate  against  the  success  of  the  treatment 
through  the  abnormal  action  of  the  inclined  cusp  planes  of  the  incisors. 
•  Often  the  lower  incisors  will  be  completely  hidden  from  view  by 
the  upper  incisors,  in  some  cases  striking  the  gums  lingual  to  the  upper 
incisors  and  causing  absorption  of  the  soft  tissues.  Again,  it  will  be 
observed  that  the  lower  incisors  occlude  with  the  gingival  ridges  of 
the  upper  incisors,  enhancing  their  protrusion,  and  initiating  an 
inflammatory  condition  of  the  peridental  membranes  of  the  upper 
incisors. 


Fig.  663. 

The  treatment  of  cases  of  Class  II,  Div,  i  presenting  with  the  deep 
overbite  varies  from  the  treatment  of  cases  of  this  class  presenting  with 
a  short  or  normal  overbite  in  that  the  plane  of  occlusion  has  to  be 
altered  until  the  overbite  is  normal.  The  lower  molars  must  be  ex- 
truded, and  oftentimes,  the  upper  or  lower  incisors  intruded  in  their 
sockets. 

If  these  cases  are  begun  before  the  eruption  of  the  bicuspids  and 
second  molars,  the  wearing  of  a  bite  plate  (Fig.  663)  to  hold  the  dental 
arches  apart,  and  the  wearing  of  the  triangular  intermaxillary  elastics 
as  in  Fig.  557  to  extrude  the  molars  will  change  the  occlusal  plane  so  that 
while  the  occlusion  of  the  molars  is  changed  from  distal  to  normal  the 
normal  overbite  is  obtained. 

The  same  method  of  treatment  will  apply  to  a  lesser  degree  in  more 
mature  cases  in  which  the  bicuspids  and  second  molars  have  erupted,. 


772 


ORTHODONTIA. 


but  occasionally  it  is  necessary  to  change  the  compensating  curve  of 

either  or  both  of  the  upper  and  lower  arches  by  the  use  of  the  expansion 

arches  as  double  elastic  levers  as  in  Fig.  608. 

A  modification  of  the  bite-plate  principle  has  been  embodied  in  an 

inclined  plane  of  26  gauge  clasp  metal,  Fig.  664,  soldered  to  the  lingual 
surface  of  gold  bands,  cemented  upon  the  upper 
central  incisors.  This  suggestion  (Reoch)  is 
adaptable  in  most  of  the  fixed  inclined  planes  in 
use  at  the  present  writing  for  changing  the  over- 
bite, and  it  is  useful  as  well  in  the  retention  of 
Fig.  664.  . 

these  cases. 

Another  form  of  the  bite  plane  is  seen  in  the  looped  wire  plane 
(Young)  attached  to  incisor  bands  as  in  Fig.  759.  In  order  to  establish 
the  bite  plane  so  that  the  upper  incisors  are  not  bound  together,  and  so 
that  each  incisor  may  have  freedom  to  exercise  its  function  in  occlusion,. 
Hawley  has  suggested  the  use  of  the  individual  staple  planes 
as  in  Fig.  661. 

Treatment  of  Special  Cases.  Case  I. — Fig.  668  repre- 
sents a  case  of  bilateral  distal  occlusion  of  a  seven-year-old 
boy  whose  facial  profile  Fig.  668  indicated  that  he  was  suf- 
fering from  mouth-breathing.  Considerable  adenoid  tissue 
was  removed  by  a  rhinologist,  and  after  a  few  days'  recu- 
peration from  this  slight  operation,  treatment  of  the  maloc- 
clusion was  inaugurated  by  first  expanding  the  dental 
arches,  opening  up  spaces  in  the  upper  arch  for  the  permanent 
laterals,  and  in  the  lower  arch  for  the  cuspids.  The  Hawley 
chart  for  a  .39  incisor  indicated  a  great  deal  of  lateral  de- 
velopment of  both  arches  which  was  obtained  with  expan- 
sion arches  before  the  treatment  for  the  distal  occlusion. 

Intermaxillary  elastics  were  then  applied  from  hooks  upon  the  upper 
expansion  arch  to  the  distal  ends  of  the  tubes  upon  the  lower  molar 
anchor  bands,  and  the  occlusion  shifted  from  distal  to  normal.  The 
final  result  in  occlusion  is  seen  in  Fig.  667.  The  before  and  after  treat- 
ment profiles  of  the  patient  are  seen  in  Figs.  668  and  669. 

Such  a  series  of  operations  as  were  performed  upon  this  patient, 
first  in  the  removal  of  the  post-pharyngeal  obstructions,  second,  the 
cure  of  the  mouth-breathing  habit,  and  third,  the  restoration  of  the 
normal  function  and  growth  of  the  dental  and  maxillary  arches  through 
scientific  arch  expansion  and  occlusal  restoration  cannot  fail  to  be  of  the 
greatest  benefit  in  cases  of  this  character. 

Case  II. — ^A  very  typical  case  of  Class  II,  Div.  i,is  illustrated  in 


Fig.  665. 


TREATMENT    OF    CLASS   II. 


773 


Fig.  666. 


Fig.  667. 


Fig.  668, 


Fig.  669. 


774 


ORTHODONTIA. 


Figs.  670  and  671,  the  before- treatment  models  on  the  left  exhibiting 
full  distal  occlusion  of  the  lower  arch,  the  protrusion  of  the  central 
incisors  in  the  upper  arch,  accompanied  by  all  the  displeasing  and  inhar- 
monious facial  lines  of  the  mouth-breather  as  seen  in  the  short  upper 


Fig.  670. 

lip,  and  the  rolling  of  the  lower  lip  under  the  upper  incisors,  illustrated 

in  the  front  and  profile  pictures  of  the  case  before  treatment  in  Fig.  666. 

The  expansion  arches  were  adjusted  to  both  upper  and  lower  dental 

arches  in  a  manner  similar  to  the  adjustment  in  Fig.  550,  ligating  the 


Fig.  671. 

anterior  teeth,  and  considerable  lateral  spring  was  given  to  the  upper 
expansion  arch  to  obtain  the  effect  of  widening  the  upper  arch  poste- 
riorly and  retruding  the  upper  incisors. 


TREATMENT    OF    CLASS    II. 


775 


The  treatment  of  the  case  was  aggravated  by  the  loss  of  the  lower 
right  first  permanent  molar,  as  it  was  necessary  to  regain  this  lost 
space  by  banding  the  second  bicuspid  and  ligating  it  to  the  lower 


Fig.  672. 


expansion  arch  by  a  spur  soldered  a  little  in  advance  of  this  tooth,  and 
turning  up  the  nut  on  the  expansion  arch  until  normal  occlusal  re- 
lations were  established,  the  intermaxillary  force  on  this  side  being 


776  ORTHODONTIA. 

made  strong  enough  by  doubling  the  elastics  to  resist  too  great  a  distal 
movement  of  the  second  molar. 

The  models  on  the  right  of  Figs.  670  and  671  illustrate  the  very  per- 
fect occlusal  relations  which  were  established,  and  the  pictures  on  the 
right  of  Fig.  072  exhibit  the  improvement  in  the  profile  as  the  result  of 
treatment. 

The  retention  in  this  case  consisted  of  interlocking  spurs  extending 
from  upper  to  lower  molar  anchor  bands,  the  upper  arch  being  also 
retained  in  its  altered  shape  by  a  lingual  arch  connected  with  the  upper 
molar  anchor  bands,  and  attached  to  incisor  and  cuspid  bands. 

Treatment  of  Class  II,  Div.  1,  Infra-occlusion. — One  of  the  most 
difficult  complications  occurring  in  any  class  of  malocclusion  is  that  of 
the  "open  bite,"  or  lack  of  occlusion  extending  from  the  central  incisors 
distally  sometimes  as  far  as  the  first  and  second  molars,  the  arches  being 
separated  anteriorly  from  one-sixteenth  to  one-half  an  inch,  according 
to  the  degree  of  malformation  present. 

The  inability  to  close  the  teeth  anteriorly  renders  mouth-breathing 
more  or  less  of  a  necessity,  since  lip  function  is  almost 'entirely  lacking 
in  these  cases,  and  the  distortion  of  the  features  is  much  more  dis- 
pleasing than  if  only  the  distal  occlusion  were  present. 

The  combination  of  "open  bite"  malocclusion  and  distal  occlusion 
is  such  as  to.  increase  the  difficulties  of  treatment,  and  sometimes 
to  baffle  the  efforts  of  the  most  expert  operator. 

In  the  treatment  of  an  "open  bite"  distal  occlusion  of  the  first  divi- 
sion of  Class  II,  the  advisability  of  applying  force  for  the  restoration 
of  the  normal  mesio-distal  relationship  simultaneously  with,  or  pre- 
vious to,  the  application  of  force  for  the  closing  of  the  bite,  will  depend 
largely  upon  the  age  of  the  patient  and  the  extent  of  the  infra- occlusion 
of  the  anterior  teeth. 

In  a  child  under  twelve  years  of  age,  the  greater  possibilities  of 
development  and  growth  of  the  alveolar  process  and  underlying  bony 
tissues  of  maxilla  and  mandible,  might  call  for  much  more  ideal  treat- 
ment than  in  a  more  mature  case. 

For  example,  the  distal  occl  usion  and  "open  bite ' '  malocclusion  would 
respond  readily  to  treatment,  and  if  normal  breathing  and  lip  function 
were  restored  and  an  effectual  retention  of  the  restored  occlusion  be 
secured  in  the  child  under  twelve  years  of  age,  success  in  the  attain- 
ment of  ideal  results  may  be  somewhat  assured. 

In  the  adult  the  conditions  for  ideal  treatment  are  very  unfavor- 
able, since,  although  it  might  be  possible  to  restore  the  normal  rela- 
tions of  occlusion  and  close  the  bite  by  the  efficient  use  of  intermax- 


TREATMENT    OF    CLASS   II. 


777 


illary  force,  the  indefinitely  continued  use  of  the  same  force,  with 
a  multiplicity  of  bands  and  wires  for  the  retention  of  the  normal  rela- 
tionship, would  render  it  somewhat  inadvisable  in  the  majority  of  cases. 

However,  there  is  a  method  of  treating  such  a  case  which  appeals 
to  the  author  as  reasonable  and  practicable,  both  from  his  own  ex- 
perience and  from  that  of  others,  viz.,  to  close  the  bite  by  grinding  down 
the  cusps  of  molars  and  bicuspids,  allowing  the  front  teeth  to  occlude. 

Case  III.-^To  illustrate,  in  Figs.  673  and  675,  is  represented  an 
"open  bite"  bilateral  distal  occlusion  of  a  fifteen  year  old  boy,  an 


Fig.  673. 


habitual  mouth-breather,  anemic  in  temperament,  and  with  so  few ^ of 
the  teeth  in  contact  that  mastication  of  his  food  was  an  impossibility. 
To  add  to  the  difficulties  of  treatment,  the  upper  right  first  and  second 
molars  were  in  lingual  occlusion,  and  the  crown  of  the  lower  left  first 
molar  was  destroyed  by  caries. 

In  order  to  be  conservative  of  anchorage,  the  first  step  in  the  treat- 
ment was  to  bring  the  upper  molars  into  buccal  positions,  and  allow 
them  to  settle  into  occlusal  relations  with  the  lower  molars  before 
proceeding  with  the  further  treatment  of  the  case. 


778 


ORTHODONTIA. 


The  expansion  arches  and  rubber  elastics  were  then  adjusted  as  in 
Fig.  556,  for  shifting  the  occlusion,  which  was  successfully  accomplished 
after  a  few  months'  treatment,  but  with  the  result  that  the  anterior  open 
bite  was  somewhat  increased,  as  is  usual  in  these  cases. 

Although  not  assured  of  successful  retention  of  the  mesio-distal 
relationship  of  the  arches  and  the  occlusion  of  the  anterior  teeth, 
intermaxillary  force  was  applied  between  the  upper  and  lower  incisors, 
cuspids,  and  bicuspids,  as  in  Fig.  650,  with  the  result  that  although 
these  teeth  moved  more  or  less  readily  into  occlusion,  the  appearance 


Fig.  674. 


was  not  as  much  improved  as  might  be  expected,  the  incisors  elongating 
to  an  abnormal  extent,  and  not  carrying  the  process  with  them. 

The  intermaxillary  force  was  withdrawn,  and  the  anterior  teeth 
allowed  to  settle  back  into  their  former  positions,  and  the  method  of 
treatment  changed  in  a  manner  that  has  proved  of  more  permanent 
value. 

The  plan  was  adopted  of  so  grinding  the  molar  cusps  of  both  upper 
and  lower  molars  to  close  the  bite  that  the  inclined  planes  could  be  made 
to  act  as  a  permanent  retention  for  the  restored  mesio-distal  relationship 


TREATMENT    OF    CLASS   II. 


779 


of  the  arches,  and  by  very  carefully  grinding  one  cusp  at  a  time,  and 
exaggerating  the  distal  inclines  of  the  lower  and  the  mesial  inclines  of 
the  upper  molar  cusps,  this  desirable  result  was  effected,  retaining  the 
normal  mesio-distal  relationship  without  the  aid  of  any  appliance  such 
as  the  interlocking  planes  usually  used  for  the  purpose. 

The  front  view  of  the  restored  occlusion  may  be  seen  in  Fig.  674, 
and  the  effectual  interlocking  of  inclined  planes  of  the  cusps  of  the 
molars  and  bicuspids  in  Fig.  676  is  of  more  than  passing  interest  in  view 
of  the  difficulties  surrounding  this  class  of  cases  in  which  distal  occlusion, 


Fig   675. 


"open  bite"  malocclusion,  and  the  confirmed  habit  of  mouth-breathing 
were  such  insurmountable  obstacles  to  any  other  method  of  treatment. 
One  very  gratifying  feature  of  the  treatment  was  that  the  boy  had 
been  examined  by  a  rhinok)gist  previous  to  coming  under  the  author's 
care,  and,  although  adenoids  had  been  found,  it  was  considered  best  to 
await  the  results  of  orthodontic  treatment  before  they  should  be  re- 
moved, and  upon  referring  the  case  back  to  the  nose  and  throat  spe- 
cialist, he  was  unable  to  find  any  adenoids,  which  was  a  surprise,  as 
such  an  occurrence  had  not  before  been  recorded. 


78o 


ORTHODONTIA. 


The  disappearance  of  these  adenoids  was  no  doubt  due  to  the  ex- 
pansion of  the  upper  arch,  and  restoration  of  normal  occlusion,  which 
gave  better  opportunities  for  normal  breathing  and  better  masticating 
function,  so  that  the  tonsillar  growths  were  reabsorbed  through  a 
restoration  of  functions  which  meant  increased  metabolism  and  con- 
sequent improved  nutrition. 

The  author  has  also  performed  the  operation  of  grinding  the  cusps  of 
the  molars  and  bicuspids  in  open  bite  malocclusions  of  the  anterior 
teeth  of  adult  cases  of  Class  I  and  Class  III  with  very  gratifying  success. 


Fig.  676. 

Care  should  be  taken  that  the  inclined  planes  be  preserved  in  the  grind 
ing,  and  be  made  to  serve  the  purposes  of  articulation  as  well  as  occlu- 
tion  by  trying  the  articular  movements  of  the  mandible  during  the  proc- 
ess, and  seeing  that  the  stress  of  articular  mastication  is  properly  sup- 
ported by  both  buccal  and  lingual  cusps  of  molars  and  bicuspids,  as  is 
done  m  the  grinding  of  artificial  teeth  upon  an  articulator  constructed 
upon  the  Bonwill  principle. 

In  very  severe  cases  of  open  bite  malocclusion,  it  may  be  found 
necessary  to  devitalize  the  pulp  of  one  or  more  of  the  molar  teeth,  since 


TREATMENT    OF    CLASS    II.  78 1 

the  pulp  cavity  will  have  to  be  partially  encroached  upon  in  order 
to  do  sufficient  grinding  to  secure  occlusion  of  the  anterior  teeth, 
and  yet  this  need  not  be  considered  an  objection  in  view  of  the  benefits 
obtained  through  the  proper  performance  of  masticatory  function, 
and  the  correction  of  the  mouth-breathing  habit. 

Treatment  of  Class  II,  Div.  1,  Subdiv.— The  characteristics  of 
the  subdivision  of  Div.  i,  Class  II,  are  very  similar  in  the  general 
appearance  of  the  dental  arches  to  those  of  the  full  first  division,  the 
upper  incisors  being  protruded,  the  upper  arch  narrow,  and  the  facial 
disfigurement  almost  identical,  the  distinguishing  feature  of  the  sub- 


FiG.  677. 

division  being  the  unilateral  distal  occlusion,  one  lateral  half  exhibiting 
normal  mesio-distal  relations. 

The  treatment,  therefore,  follows  along  the  same  lines  as  if  the 
occlusion  was  distal  bilaterally,  except  that  it  is  obviously  imnecessary 
to  shift  the  occlusion  on  the  normal  side,  although  intermaxillary 
elastics  of  less  strength  may  be  applied  on  that  side  to  assist  in 
balancing  the  forces  on  each  side  of  the  mouth. 

Case  IV. — ^Figs.  677  and  679  exhibit  a  case  of  Class  II,  Div.  i,  sub- 
division, in  which  the  right  lateral  half  is  m  distal  occlusion,  the  left 
being  in  normal  mesio-distal  relations  in  the  region  of  the  first  permanent 


782 


ORTHODONTIA. 


molars.  The  space  for  the  eruption  of  the  lower  left  second  bicuspid 
being  partially  lost  through  premature  loss  of  the  deciduous  second 
molar,  the  lower  left  first  bicuspid  and  cuspid  drifted  into  this  space  until 
they  occupied  distal  positions. 

The  expansion  arches  were  applied  in  the  same  manner  as  de- 
scribed for  the  treatment  of  the  full  bilateral  distal  occlusion,  the  mesial 
force  upon  the  lower  left  first  molar  being  compensated  by  the  distal 
force  exerted  by  the  expansion  arch  in  forcing  the  lower  left  cuspid  and 
first  bicuspid  mesially  into  their  normal  positions.  This  latter  move- 
ment was  expedited  by  ligating  from  a  lingual  spur  upon  a  band  on  the 


Fig.  678. 

first  bicuspid  to  a  spur  on  the  expansion  arch  slightly  forward  of  the 
first  bicuspid. 

After  restoring  the  size  and  shape  of  the  individual  arches,  and 
shifting  the  occlusion  to  normal  relations,  the  result  shown  in  Figs.  678 
and  680,  in  right  and  left  occlusion,  was  obtained. 

Intermaxillary  retention  was  used  in  this  case  for  a  few  months 
only,  as  the  tendency  of  the  dental  arches  was  to  remain  in  normal 
relations  after  normal  occlusion  and  function  of  the  occlusal  planes  had 
been  restored. 

Treatment  of  Class  II,  Div.  2. — The  occlusal  characteristics  of  the 
second  division  of  Class  II  include  a  distal  occlusion  of  both  lateral 


TREATMENT   OF   CLASS    II. 


783 


Fig.  679. 


Fig.  680. 


784 


ORTHODONTIA. 


halves  of  the  dental  arches,  with  contraction  of  the  anterior  portion  of 
the  upper  arch,  usually  presenting  with  some  of  the  upper  incisors  in- 
clining lingually,  or  overlapping,  as  illustrated  in  the  classification  chart. 

As  with  the  first  division  of  this  class,  the  profile  shows  the  effect 
of  the  distal  occlusion,  though  not  to  such  a  marked  degree,  the  lower 
third  of  the  face  being  more  uniformly  receded  from  the  normal  pose. 

Although  cases  of  this  division  are  usually  normal  breathers,  it  is 
not  unusual  to  find  mouth-breathers  among  them. 


Fig.  68 1. 


The  distal  occlusion  in  this  division  is  probably  in  existence  in  the 
deciduous  arches  before  the  eruption  of  the  first  permanent  molars, 
and  the  upper  incisors  are  forced  into  lingual  and  overlapping  positions 
through  Nature's  effort  to  conform  the  arches  to  some  uniformity  in 
size  for  better  occlusion,  the  pressure  of  the  lips  being  powerful  factors 
in  such  arch  conformation. 

Case  V. — ^Fig.  68i  illustrates  the  right  occlusion  of  a  case  of  bilateral 
distal  occlusion  in  an  eleven  year  old  child,  the  upper  central  incisors 
inclining  lingually  and  overlapped  by  the  lateral  incisors.  In  the  treat- 
ment of  this  case,  the  intermaxillary  elastics  were  applied  for  shifting  the 
occlusion  to  normal  mesio-distal  relations,  keeping  the  upper  central 


TREATMENT   OF    CLASS   II. 


785 


incisors  clear  of  the  lower  incisors  by  expanding  the  upper  arch  and 
moving  the  deflected  central  incisors  towards  their  normal  positions  a 
little  in  advance  of  the  mesial  movement  of  the  lower  dental  arch. 

The  restoration  of  normal  relations  of  occlusion  in  Fig.  682  is  of 
exceptional  interest  in  that  the  mesio-distal  relations  of  the  arches  were 
not  artificially  retained,  the  normal  function  of  occlusal  planes  of 
the  teeth  being  sufficient  to  hold  the  dental  arches  in  their  normal 
pose.  The  only  retaining  appliance  worn  consisted  of  a  lingual  retainer 
for  the  upper  central  incisors,  being  attached  to  bands  upon  the  lateral 
incisors. 

Treatment  of  Class  II,  Div.  2,  Subdivision. — The  occlusal  rela- 
tions of  one  lateral  half  of  the  dental  arches  being  normal  in  the  sub- 


FlG.  682. 


division  of  the  second  division  of  Class  II,  treatment  for  shifting  the 
occlusion  is  necessary  only  upon  the  lateral  half  which  exhibits  distal 
occlusion.  Expansion  of  both  arches,  however,  may  be  necessary,  in 
order  to  secure  normal  size  and  shape  of  the  dental  arches. 

Case  VI. — A  characteristic  case  of  this  subdivision  is  illustrated, 
before  and  after  treatment,  in  Figs.  683  and  684,  right  occlusion,  and 
685  and  686,  left  occlusion. 
5° 


786 


ORTHODONTIA. 


Fig.  683. 


Fig.  684. 


TREATMENT   OF    CLASS    II. 


787 


Fig.  685. 


Fig.  686. 


788 


ORTHODONTIA. 


The  distal  occlusion  is  on  the  right  lateral  half,  and  the  apparent 
simulation  of  a  distal  occlusion  on  the  left  side  is  due  to  the  closing  up 
of  the  space  for  the  lower  second  bicuspid  which  is  unerupted,  allow- 
ing the  first  bicuspid  to  drift  back  until  it  is  in  contact  with  the  first 
molar,  carrying  along  with  it  by  lack  of  anterior  development,  the  cus- 
pid and  incisors  on  the  left  side. 

An  X-ray  of  the  left  side  of  the  mandible  revealed  the  presence  of 
the  second  bicuspid  in  its  proper  place  but,  of  course,  unerupted. 

Upon  the  adjustment  of  the  expansion  arches,  the  upper  with  hooks 


Fig.  687. 


for  the  intermaxillary  elastics,  and  the  lower  with  a  spur  opposite  the 
lower  first  bicuspid  which  was  banded  and  ligated  to  the  spur,  the 
intermaxillary  elastics  were  applied  to  both  sides  of  the  arches,  that 
on  the  right  being  adjusted  to  shift  the  distal  occlusion  to  normal, 
and  the  one  on  the  left  to  re-enforce  the  lower  molar  anchorage  which 
is  to  resist  the  force  used  to  move  the  cuspid  and  bicuspid  on  that  side 
forward  in  the  line  of  the  arch. 

Immediately  upon  the  removal  of  the  appliances,  the  case  presented 
the  appearance  seen  in  Fig.  687,  in  which  the  anterior  part  of  both  arches 
seems  to  be  abnormally  protruded,  a  condition  which  it  has  been  er- 


TREATMENT    OF    CLASS   III. 


789 


roneously  claimed  the  orthodontists  of  the  "  new  school"  are  apt  to  ob- 
tain as  a  result  of  their  treatment  without  extraction. 

From  four  to  six  weeks  after  this  model  was  made,  the  teeth  had 
settled  back  through  the  guidance  of  the  retaining  appliances  to  the 
beautiful  relations  of  occlusion  shown  in  Figs.  684  and  686. 


Fig. 


Fig.  6S9. 


The  before  and  after  treatment  profiles  of  this  case,  Figs.  688  and 
689,  show  a  decided  improvement  in  the  art  relations  of  the  face. 

PART   X. 
TREATMENT  OF  CLASS  III. 

Diagnosis  of  Class  III. — This  class  presents  with  bilateral  or 
unilateral  mesial  occlusion  of  the  lower  dental  arch,  and,  in  the  extreme, 
is  probably  the  most  disfiguring  of  any  class  of  malocclusion.  In 
cases  of  this  class  the  maxilla  is  usually  considerably  arrested  in  develop- 
ment, and  the  mandible  protruded,  with  its  incisors  inclining  lingually. 

Most  all  of  the  cases  of  Class  III  are  mouth-breathers,  and  naso- 
pharyngeal obstructions  are  unusually  persistent.  Accompanying 
many  of  these  cases  is  the  condition  of  "open  bite"  malocclusion  with 
its  added  difficulties  of  treatment. 

The  inception  of  mesial  occlusion  is  during  a  very  early  period  in 
child  life,  when  it  is  least  noticeable  in  the  facial  lines,  and  yet  it  is  at 


790 


ORTHODONTIA. 


this  early  period  when  the  malocclusion  should  be  diagnosed  and  the 
abnormal  conditions  overcome  which  are  causative  of  it,  if  the  most 
beneficial  results  are  to  be  obtained. 

In  severe  cases  of  this  class,  the  angles  formed  by  the  rami  and  body 
of  the  mandible  disappear,  leaving  almost  a  straight  line  from  the  chin 
to  the  ear.  These  cases  may  usually  be  diagnosed  from  the  profile,  the 
mandible  being  protruded,  and  the  upper  lip  receding. 

The  conditions  of  arrested  development  are  usually  persistent,  the 
upper  arch  remaining  small  and  undeveloped,  and  the  lower  arch 
changing  in  form  according  to  the  general  direction  of  abnormal  ten- 
sion of  muscles. 

The  etiological  factors  are  somewhat  obscure,  although  it  is  believed 
that  the  habit  of  holding  the  mandible  forward  to  assist  in  breathing 
when  the  faucial  tonsils  are  hypertrophied,  has  a  strong  tendency  to 
cause  the  mesial  occlusion. 


Fig.  6qo. 


Hypertrophied  or  diseased  tonsils  should  beremoved'as  early  as  diag- 
nosed, since  if  they  are  allowed  to  remain,  it  is  impossible  to  overcome 
the  faulty  breathing,  and  abnormal  relations  of  muscles  which  persist 
in  holding  the  mandible  forward. 

Technic  of  Operative  Treatment  in  Class  III. — The  operative 
treatment  of  Class  III  may  be  divided  into  two  stages,  the  restoration  of 
the  normal  size  and  shape  of  the  dental  arches,  and  the  shifting  of  the 
occlusion  from  mesial  to  normal  relations. 

The  use  of  the  intermaxillary  force  for  shifting  the  occlusion  is 
necessary,  as  in  Class  II,  although  the  direction  of  the  force  and  the 
manipulation  of  the  anchorage  is  exactly  the  reverse  from  that  in  the 
second  class. 


TREATMENT   OF    CLASS    III.  79 1 

The  direction  and  points  of  application  of  the  intermaxillary  force 
in  treatment  of  Class  III  may  be  seen  in  Fig.  690,  the  elastics  extend- 
ing from  the  distal  ends  of  the  tubes  on  upper  molar  clamp  bands, 
to  the  hooks  on  the  lower  expansion  arch. 

The  expansion  arches  are  illustrated  without  ligatures,  so  that  the 
intermaxillary  anchorage  may  be  more  clearly  shown.  In  actual 
treatment,  proper  ligation  of  the  teeth  in  both  dental  arches  to  the  expan- 
sion arch  should  be  made  according  to  the  tooth  movements  desired,  and 
the  degree  of  re-enforced  anchorage  necessary  in  either  arch. 

It  is  also  necessary,  in  extreme  cases  of  this  class,  to  shift  the  anchor 
bands  from  first  molars  to  bicuspids  in  the  lower  arch,  in  order  to  con- 
serve anchorage  and  secure  distal  movement  of  the  bicuspids. 


Fig.  691, 

Owing  to  the  fact  that  mesial  movement  of  the  teeth  requires 
less  force  than  distal  movement,  appliances  almost  always  operate 
to  move  the  teeih  of  the  upper  arch  mesially  more  than  to  move  the 
teeth  of  the  lower  arch  distally  in  these  cases. 

It  is  considered  especially  advantageous  in  this  class  of  cases  to 
obtain,  if  possible,  a  deep  overbite,  or  overlapping  of  the  upper  over  the 
lower  incisors  after  shifting  of  the  occlusion,  as  the  increased  length 
of  the  inclined  cusp  planes  serves  to  more  efifectually  retain  the  restored 
relations  of  occlusion  than  where  but  a  short  overlapping  is  present. 

It  is  advisable  to  begin  the  treatment  of  this  class  of  malocclusion 
as  early  as  it  is  possible  to  manage  the  child,  for  with  added  years  comes 
an  exaggeration  of  the  deformity,  the  mandible  assuming  a  more  for- 
ward pose,  and  the  shape  of  the  bone  and  the  relations  of  the  muscles 


792  ORTHODONTIA. 

becoming  conformed  to  an  abnormal  condition  which  makes  it  much 
more  difficult  and  sometimes  impossible  to  completely  overcome. 

Case  I. — Fig.  691  exhibits  the  model  of  the  case  of  the  seven- 
year-old  boy,  from  whose  throat  the  adenoids  and  tonsils  shown  in  Fig. 
492  were  removed  at  the  beginning  of  treatment. 

Anchor  bands  were  fitted  to  the  deciduous  second  molars  and  the 
18  gauge  expansion  arches  adjusted  as  in  Fig.  690,  the  intermaxillary 
elastics  being  attached  in  the  same  manner  as  in  a  dental  arch  of  per- 
manent teeth. 

The  occlusion  was  changed  in  a  few  weeks  to  that  shown  in  Fig.  692 
and  a  persistent  retention  by  means  of  the  buccal  spurs  was  established, 
and  the  case  dismissed  to  be  seen  only  at  intervals  of  a  couple  of  months, 


Fig.  692. 

until  the  permanent  teeth  should  erupt,  in  order  that  any  untoward 
developments  might  receive  immediate  attention,  should  they  arise. 

The  profile  pictures  of  this  case  are  exhibited  in  Figs.  693  and  694. 
After  a  year's  retention,  the  development  of  the  facial  lines  through 
the  establishment  of  normal  functions  of  occlusion  and  respiration 
has  been  most  gratifying. 

Case  II. — Another  case  of  this  class,  the  before  treatment  models  of 
which  are  shown  in  Fig,  695,  and  which  was  treated  by  M.  T.  Wat- 
son, is  unusually  interesting  in  view  of  the  fact  that  the  restoration  of 
occlusion  and  facial  lines  was  accomplished  solely  by  means  of  the 
Angle  chin  cap  and  headgear,  a  combination  which  has  fallen  somewhat 
into  disuse  since  the  general  adoption  of  intermaxillary  force  for  the 
mesio-distal  changes  in  occlusion. 


TREATMENT    OF    CLASS    III.  793 

Beginning  with  a  very  gentle  elastic  pressure  for  the  first  few  days 
of  treatment,  two  No.  33  Goodyear  elastic  bands  were  adjusted  between 
headgear  and  chin  on  each  side,  followed  in  the  course  of  a  week 


Fig.  693.  Fig.  694. 

by  the  substitution  of  a  No.  oooj  for  the  lower  of  the  two  bands,  which 
represented  the  maximurn  of  force  used  in  the  treatment. 

Aside  from  a  slight  crowding  of  the  lower  incisors,  the  results 
of  about  six  weeks'  treatment  produced  almost  normal  mesio-distal 


Fig.  695. 

relations  of  the  dental  arches,  the  final  occlusal  relations  established 
being  shown  in  Fig.  696.  The  necessity  for  the  subsequent  use  of  appli- 
ances inside  of  the  mouth  for  perfecting  the  occlusal  relations  does  not 
detract  from  the  scientific  value  of  the  method  just  described  for  early 
treatment  of  this  class  of  cases,  especially  as  it  is  the  only  recorded  case 


794 


ORTHODONTIA. 


in  which  the  treatment  was  confined  solely  to  the  use  of  the  chin  re- 
tractor, and  therefore  exhibiting  "  a  change  which  must  necessarily  be 
confined  to  the  shape  of  the  mandible  itself,  or  to  a  change  in  the  tem- 
poro-maxillary  articulation,  or  both,  the  latter  probably  being  the  case." 
(Watson.) 


Fig  696. 

Fig.  697  illustrates  the  before  and  after  treatment  profiles  of  the 
case,  the  latter  picture  being  taken  about  four  months  after  the  first 
one.  The  slight  prominence  of  the  lower  lip  in  comparison  with  the 
upper  may  be  accounted  for  by  the  loss  of  the  upper  deciduous  central 
incisors  during  the  treatment,  and  the  lack  of  the  permanent  centrals 
being  sufficiently  erupted  to  lend  any  contour  to  the  upper  lip. 


Fig.  697. 


Case  m. — ^A  comparatively  simple  case  of  this  class  is  illustrated  in 
Fig.  698  before  and  after  treatment.  This  case  was  undertaken  just 
as  the  bicuspids  were  erupting  to  occlusion  and  the  change  from  mesial 
to  normal  occlusion  as  a  result  of  treatment  gave  the  cuspids  and  bicus- 


TREATMENT    OF    CLASS    DI. 


795 


pids  an  opportunity  to  complete  their  eruption  into  normal  locking  with 
the  inclined  planes  of  their  antagonists. 

The  expansion  arches  were  placed  upon  both  upper  and  lower  arches 
and  the  intermaxillary  elastics  stretched  from  hooks  soldered  well 
forward  upon  the  lower  expansion  arch  to  the  distal  end  of  the  buccal 
tubes  upon  the  upper  molar  clamp  bands,  as  in  Fig.  690.  When  the 
upper  incisors  are  but  slightly  distal  to  the  lower  incisors  as  in  this 
case,  the  first  effort  should  be  directed  to  moving  the  upper  incisors 
into  positions  mesial  to  the  lower  incisors,  so  as  to  gain  the  advantage 
of  the  inclined  planes  of  the  lingual  surfaces  of  the  upper  incisors 
acting  upon  the  labial  inclined  planes  of  the  lower  incisors  during  the 
rest  of  the  treatment,  for  until  this  change  is  made,  the  reverse  action 


Fig.  698. 

of  the  inclined  planes  of  the  incisors  will  tend  to  prevent  a  change  in 
occlusion  of  the  molars. 

To  accomplish  this  movement  of  the  upper  incisors,  the  lower  ex- 
pansion arch  was  securely  ligatured  to  the  lower  incisors  and  bicuspids, 
and  the  lower  arch  used  as  a  stationary  anchorage,  as  it  were.  The 
upper  incisors  were  then  ligated  to  the  upper  expansion  arch,  the  nuts 
in  front  of  the  anchor  tubes  turned  up  tight  twice  a  week  and  the  inter- 
maxillary force  being  constantly  in  action,  not  only  prevented  the  upper 
molars  from  distal  movement,  but  hastened  the  mesial  movement  of 
the  upper  incisors. 

After  this  change  in  the  occlusion  of  the  incisors  was  effected,  the 
intermaxillary  force,  continuing  in  action,  produced  the  change  from 
mesial  to  normal  occlusion  of  the  lower  molars.  It  will  be  ob-served 
from  the  cut  that  some  expansion  of  both  arches  was  accomplished  at 
the  same  time. 


796 


ORTHODONTIA. 


Even  with  such  a  slight  change  in  occlusion  as  is  exhibited  in  this 
case,  a  very  decided  improvement  in  the  facial  lines  is  seen  in  the  com- 
parison of  the  before  and  after  treatment  profiles  in  Figs.  699  and  700. 

Case  IV. — A  much  more  difficult  case  than  the  one  just  described 
on  account  of  increased  age  and  consequent  greater  density  of  alveolar 
tissues  and  conformation  of  occlusion  and  facial  lines  to  abnormal 
conditions  is  illustrated  in  Fig.  701,  the  before  and  after  treatment 
models  being  observed  from  the  left  side. 


Fig.  699. 


Fig.  700. 


Orthodontists  have  been  cautioned  against  the  possibility  of  ab- 
normal eruption  of  the  lovi^er  third  molars  during  or  after  the  period 
of  distal  movement  of  the  lower  second  and  first  molars  in  cases  of  this 
class,  and  while  it  is  advisable  to  observe  unusual  precautions  to  pre- 
vent any  maleruption  of  these  teeth,  the  experience  of  the  author  in 
this  case  and  other  similar  cases,  leads  him  to  believe  that  in  the  majority 
of  cases  the  restoration  of  occlusion  and  consequent  proper  function  of 
the  maxillae,  may  aid  rather  than  interfere  with  the  normal  develop- 
ment of  the  third  molars.  The  lower  third  molars  in  this  case  erupted 
into  their  normal  positions  soon  after  treatment  was  finished,  and  with 
no  more  difficulty  than  if  the  operation  had  not  been  performed. 

The  change  in  the  profile  is  apparent  from  a  comparison  of  the 
before  and  after  treatment  pictures  in  Fig.  702. 

Case  V. — ^There  are  many  cases  occurring  in  practice  which  seem  t« 
be  exceptionally  difficult  to  diagnose  and  treat  on  account  of  the  loss  of 


TREATMENT   OF    CLASS   III. 


797 


many  of  the  permanent  teeth,  and  the  consequent  complications  caused 
by  the  migration  and  elongation  of  remaining  teeth  in  already  contracted 
arches. 


Fig   701. 


Fig.  702. 


A  case  of  this  character,  age  twenty  years,  belonging  to  Class  III,  is 
exhibited  in  Figs.  703  and  704,  before  and  after  treatment  of  both  right 
and  left  sides  of  the  mouth.     The  loss  of  many  of  the  teeth  by  caries 


798  ORTHODONTIA. 

and  necessary  extraction,  and  the  elongation  of  teeth  which  had  no 
antagonists,  rendered  it  exceedingly  difficult  to  treat,  especially  as  the 
problems  of  anchorage  for  the  use  of  intermaxillary  force  seemed 
rather  uncertain. 


Fig.  703. 

By  a  careful  conservation  of  anchorage,  however,  the  case  was  finally 
brought  to  a  successful  completion,  the  after  treatment  models  being 
shown  on  the  right  of  Figs.  703  and  704,  with  retaining  appliances  in 
position. 


Fig.  704. 

In  this  case  the  plate  plays  a  very  important  part,  not  only  in  retain- 
ing temporarily  the  spaces  regained  for  permanent  teeth,  but  also  supply- 
ing artificial  substitutes  for  the  missing  natural  teeth. 

A  view  of  the  upper  casts  of  this  case  in  Fig.  705  shows  the  retention 
of  five  of  the  anterior  teeth  with  a  lingual  wire  soldered  to  the  left 


TREATMENT    OF    CLASS   III. 


799 


cuspid  and  right  lateral  incisor  bands,  and  a  roof  plate,  with  spring 
clasp  attachments  and  three  artificial  teeth,  effecting  the  retention  of 
the  rest  of  the  teeth  in  the  upper  arch. 

Another  plate  with  spring  clasp  attachments  and  artificial  substi- 


FlG.  70: 


tutes  for  natural  teeth,  accomplishes  the  greater  part  of  the  retention 
of  the  lower  arch  as  illustrated  in  Fig,  706.  The  profile  of  this  case, 
before  and  after  treatment,  is  exhibited  in  Fig.  707,  the  improvement  in 
facial  contour  being  very  pleasing. 


Fig.  706 


At  a  later  period,  the  plates  were  removed  and  bridge- work  inserted 
for  permanent  retention  and  increased  function  of  mastication  which 
was  attained. 

Case  VI. — A  case  like  that  illustrated  in  Fig.  708,  pre- 
sents such  difficulties  in  the  way  of  treatment,  that  the  operation  of 


8oc 


ORTHODONTIA. 


resection  of  the  mandible  for  the  purpose  of  securing  the  best  results 
in  improved  mastication  and  facial  contour  has  occasionally  been 
recommended. 

The  infrequency  of  the  operation  of  mandible  resection,  and  the 
reports  of  a  few  failures  in  the  hands  of  incompetent  surgeons, 
has  not  aided  in  making  it  more  desirable.  The  operation  has  been 
successfully  accomplished  by  the  general  surgeon,  and  it  is  be- 
lieved by  the  author  that  in  the  near  future,  it  will  be  more  commonly 
performed  and  by  the  trained  oral  surgeon,  especially  with  the  help  of 
the  orthodontist. 

In  the  particular  case  illustrated  in  Fig.  708,  the  author  performed 
an  orthopedic  operation  which   resulted  not  only  in  improvement  in 


Fig.  707. 


masticatory  occlusion,  but  in  a  transformation  of  the  disfigured  facial 
lines  into  those  of  a  most  pleasing  character,  besides  restoring  the  func- 
tion of  correct  phonation  in  speaking. 

The  operation  consisted  in  opening  up  an  artificial  space  upon  each 
lateral  half  of  the  maxilla,  between  the  cuspid  and  first  bicuspid,  the 
width  of  a  bicuspid  tooth,  moving  the  six  anterior  teeth  forward  to 
occlusion  with  the  lower  incisors,  by  a  conservative  use  of  intermaxillary 
force  and  special  manipulation  of  the  expansion  arches. 

At  the  same  time,  the  teeth  in  the  lower  arch  were  moved  distally 
as  far  as  distal  inclination  of  the  lower  incisors,  and  the  accompanying 
movements  of  the  upper  teeth  would  allow,  until  the  result  shown  in 
Fig.  709  was  attained.     The  upper  arch  was  retained  by  a  fixed  lingual 


TREATMENT   OF    CLASS    III. 


8oi 


arch  soldered  to  bands  upon  the  cuspids  and  first  bicuspids,  with  buc- 
cal hooks  upon  the  bicuspid  bands,  and  with  elastics  extending  from 
these  to  hooks  on  lower  cuspid  bands  for  a  continuation  of  the  in- 
termaxillary force  as  retention. 

Artificial  teeth,  soldered  to  the  lingual  retaining  wire,  artistically 
filled  up  the  opened  spaces  until  such  time  as  permanent  bridge-work 
could  be  substituted  for  the  retention. 


Fig.  708. 

The  improvement  in  the  profile  may  be  seen  upon  comparison  of 
the  before  and  after  treatment  pictures  in  Figs.  710  and  711. 

Case  VII. — ^Double  Resection  of  the  Mandible  in  Class  III. — We 
are  indebted  to  Max  Ballin  for  the  first  published  illustrations  of  a  suc- 
cessfully operated  case  of  double  resection  of  the  mandible,  a  brief 
description  of  which  is  given  here  in  condensed  form. 

The  patient  was  a  young  man  twenty-two  years  of  age,  who  pre- 
sented himself  to  the  surgeon  on  May  10,  1907,  for  possible  surgical 
treatment  of  a  protruded  mandible,  which  orthodontic  treatment  had 
for  some  reason  failed  to  remedy. 

The  extent  of  the  protrusion  measured  one-half  inch  from  the  labial 

SI 


802 


ORTHODONTIA. 


surfaces  of  the  upper  incisors  to  the  lingual  surfaces  of  the  lower  incisors, 
and  the  relations  of  the  two  dental  arches  in  occlusion  was  such  that  it 
was  almost  impossible  to  masticate  the  food.     (See  Fig.  712.) 

The  loss  of  several  teeth  from  each  lateral  half  of  the  mandible 
left  spaces  in  which  considerable  resorption  of  the  process  had  taken 
place,  and  from  which  it  was  thought  advisable  to  cut  comparatively 
uniform  sections  of  the  mandible,  and  readjust  and  unite  the  anterior 
and  posterior  sections. 


Fig.  709. 


Previous  to  operating.  Angle's  fracture  bands  were  fastened  to  the 
teeth  on  either  side  of  the  area  from  which  the  sections  were  to  be 
cut,  by  a  dentist  who  was  called  in  consultation.  The  operation  was 
performed  on  May  20,  1907,  at  Harper  Hospital,  Detroit.  Ether  was 
administered,  and  the  incision  made  in  the  soft  tissues  under  the  lower 
border  of  the  body  of  the  mandible.  The  soft  tissues  were  separated 
from  the  buccal  and  lingual  surfaces  of  the  bone  in  the  region  to  be 
resected,  and  the  mucous  membrane  was  detached  from  the  alveolar 
process  with  a  curved  bistoury,  care  being  taken  not  to  make  the 
slightest  entrance  into  the  oral  cavity. 


TREATMENT   OF   CLASS   in. 


803 


A  trapezoid  shaped  piece  was  then  resected  from  the  mandible 
with  a  circular  saw  driven  by  an  electric  engine  such  as  is  used  for  tre- 
phining. In  repeating  the  operation  upon  the  other  half  of  the  man- 
dible, the  old  style  chain  saw  was  found  to  work  much  easier  and  took 
considerable  less  time.  A  Deschamps  aneurysmal  needle  was  used  to 
lead  the  saw  around  the  mandible.  The  base  of  the  resected  pieces 
was  about  one-half  inch  in  length  and  somewhat  longer  than  the 
apices. 


Fig.  710. 


Fig.  711. 


Holes  were  drilled  through  the  lower  edges  of  the  remaining  seg- 
ments of  the  mandible,  the  segments  were  adjusted  together,  and  silver 
wires  were  inserted  from  one  segment  to  the  other  on  each  side.  After 
suturing  the  external  wound,  the  union  of  the  segments  was  made  more 
secure  by  the  ligating  of  the  buttons  upon  the  fracture  bands  within 
the  mouth,  from  the  teeth  on  the  anterior  segment  to  those  upon  the 
posterior  segments. 

The  entire  operation,  with  the  exception  of  the  ligation  of  the 
fracture  bands,  was  performed  outside  of  the  mouth,  so  as  to  make  it 
as  aseptic  as  possible. 

The  patient  made  a  quick  recovery,  being  in  the  hospital  about 
one  week,  the  wound  healing  by  first  intention.  The  after-treatment 
model  in  Fig.  713  and  profile  in  Fig.  714  show  a  marked  improvement 
over  former  conditions. 

Ballin  remarks:    "In  the  first  place,  strict  asepsis  should  be  a 


804  ORTHODONTIA. 

condition  without  which  successful  work  is  impossible.  Therefore, 
opening  of  the  oral  cavity  during  the  operation  should  not  occur  as 
this  would  certainly  lead  to  suppuration  and  non-union  of  the  bones. 
If  the  teeth  are  extracted  during  the  operation,  communication  between 
the  external  incision  arid  the  extraction  wound  will  always  take  place. 
I  would  recommend,  therefore,  to  extract  the   teeth  necessary  to  be 


Fig.  712. 

removed  for  the  resection,  first,  and  then  wait  some  months  until  the 
extraction  wound  is  completely  healed  and  atrophy  of  the  alveolar  proc- 
ess has  taken  place." 

In  commenting   upon    this   operation,  the  author  believes    that 
Ballin   has  solved  the  difficulties  in  the  way  of  preventing  the  in- 


TREATMENT   OF   CLASS  IV. 


805 


ception  of  septic  conditions,  in  operating  entirely  external  to  the  oral 
cavity. 

One  suggestion  made  by  Angle  in  regard  to  preparation  for  this 
operation  seems  an  improvement  in  the  technic  and  that  is  the  re- 
section of  the  previously  made  plaster  cast  of  the  mandible,  and  re- 
adjustment with  the  upper  cast  for  the  purpose  of  obtaining  the  best 
occlusion,  and  cutting  out  a  section  of  the  mandible  which  most  nearly 
approximates  the  plaster  section  which  was  removed.  In  this  way, 
the  lines  of  direction  for  the  chain  saw  might  at  least  be  approximated 


Fig.  713. 


Fig.  714. 


more  perfectly  than  without  any  measurements,  and  the  mandible 
better  adjusted  for  occlusal  relations. 

In  any  event,  the  co-operation  of  surgeon  and  orthodontist  seems 
advisable  in  working  out  the  details  of  double  resection  of  the  man- 
dible in  order  that  the  peculiar  skill  and  experience  of  each  may  serve 
the  purpose  of  obtaining  the  most  beneficial  and  scientific  results. 


PART  XL 

TREATMENT  OF  CLASS  IV. 

Diagnosis  of  Class  IV. — ^The  characteristics  in  occlusion  of  Class 
rV  being  a  mesial  occlusion  upon  one  lateral  half,  and  a  distal  occlusion 
upon  the  other  lateral  half  of  the  dental  arches,  as  observed  in  the  classi- 


8o6  ORTHODONTIA. 

fication  chart,  the  indications  for  treatment  are  a  distal  shifting  of  the 
occlusion  on  one  side,  and  a  mesial  shifting  of  the  occlusion  on  the  other 
side  of  the  arches. 

These  movements  may  be  secured  at  the  same  time  by  operating 
upon  each  lateral  half  as  if  they  were  independent  of  the  other  in  their 
mesio-distal  relationship,  making  use  of  the  intermaxillary  force  as 
indicated  by  the  attachment  of  hooks  and  elastics  in  Fig.  715,  the 
elastic  extending  from  a  hook  upon  the  upper  expansion  arch  upon  one 
side  to  the  distal  end  of  the  tube  on  the  lower  molar  clamp  band,  and 
from  a  hook  upon  the  lower  expansion  arch  to  the  distal  end  of  the 
buccal  tube  on  the  upper  molar  clamp  band  upon  the  other  side. 


Fig.  715. 

The  cases  presenting  with  Class  IV  characteristics  are  so  rare  that 
they  are  seldom  reported.  The  few  cases  that  have  been  reported  have 
been  treated  as  described  with  a  fair  degree  of  success. 

PART  XII. 
THE  PROBLEM  OF  EXTRACTION. 

Extraction  of  the  teeth  of  either  deciduous  or  permanent  set  in 
orthodontia,  must  be  viewed  from  a  different  standpoint  than  in 
general  dental  practice,  since  the  whole  aim  of  the  orthodontist  is 
the  restoration  of  the  dental  arches  in  occlusion  with  the  full  comple- 
ment of  teeth,  while  the  dentist  is  intent  upon  the  restoration  of  contour, 
etc.,  of  the  individual  tooth. 

If  the  general  practitioner  could  see  his  work  through  the  light 
of  occlusion,  articulation  and  development,  all  of  his  cases  for  bridge- 
work  would  be  sent  to  the  orthodontist  for  restoration  of  normal 


THE  PROBLEM  OF  EXTRACTION. 


807 


sized  arches,  and  the  regaining  of  spaces  partially  or  completely, 
from  which  teeth  have  been  extracted. 

The  radical  departure  from  the  older  methods  of  treatment  by  the 
"new  school"  of  orthodontia  in  the  adoption  of  conservative  methods 
of  treatment,  bases  its  assurance  of  propriety  upon  the  premises  that 
in  the  attainment  of  the  normal  and  ideal  in  occlusion,  all  of  the 
dental  organs  must  be  preserved  in  the  correction  of  malocclusion. 

This  arbitrary  standard  is  not  made  by  the  specialist,  but  it  is 
indicated  by  the  perfection  of  the  occlusion  in  the  normal  and  ideal, 
in  which  is  recognized  the  value  of  the  individual  tooth  as  a  factor 
in  the  preservation  of  the  integrity  and  regularity  of  the  arches  of  teeth, 
the  loss  of  one  or  more  teeth  from  either  arch  causing  deformity  to 
just  the  degree  of  extraction  which  is  resorted  to. 


Fig.  716. 


With  this  conception  of  treatment  in  orthodontia,  extraction  as  a 
beneficial  procedure,  that  is,  towards  restoring  the  normal  in  occlu- 
sion, is  of  course  absurd,  for  with  extraction  comes  mutilation  of  the 
arches,  impairment  of  speech  and  mastication,  and  the  formation  of 
lines  of  inharmony  in  the  face  which  are  surely  not  desirable  as  a 
result  of  the  efforts  of  the  orthodontist. 

A  very  large  per  cent,  of  the  deformed  arches  of  teeth  which  present 
to  the  specialist,  are  caused  by  the  premature  extraction  of  deciduous 
teeth,  or  the  unwise  extraction  of  permanent  teeth. 

A  very  firequent  question  asked  of  the  specialist  by  parents  is  as 
to  the  advisability  of  extraction  of  one  or  more  of  the  deciduous  teeth 
in  the  mouths  of  their  children  to  "make  room"  for  the  permanent 
teeth.     The  acquiescence  by  the  dentist  in  the  unwisdom  of  this  falla- 


8o8  ORTHODONTIA 

cious  and  pernicious  idea  has  led  to  the  wholesale  extraction  of  decidu- 
ous teeth  in  the  vain  hope  that  the  space  thus  created  will  allow  the 
permanent  teeth  more  room  to  erupt. 

The  result  of  such  operations  is  just  exactly  the  reverse  of  that 
which  is  intended,  for  the  dental  arch  instead  of  being  any  larger, 
becomes  still  more  contracted  through  the  contraction  of  the  space  of 
the  lost  deciduous  teeth,  and  the  permanent  teeth  have  less  room 
to  erupt  than  if  none  of  the  deciduous  teeth  had  been  extracted. 

Results  of  Extraction  of  Deciduous  Laterals. — For  example,  in 
the  cast  on  the  left  of  Fig.  716,  the  deciduous  lateral  incisors  were  re- 
moved in  the  belief  that  the  two  permanent  centrals  would  have  more 
room  for  eruption,  as  they  were  apparently  crowding  somewhat  in 
their  effort  to  erupt.  As  a  result  of  this  treatment,  the  centrals 
erupted  almost  perfectly  in  alignment,  but  it  will  be  noticed  that  their 
distal  angles  are  almost  in  approximation  with  the  deciduous  cuspids, 


Fig.  717. 

and  that  there  is  no  space  left  for  the  eruption  of  the  permanent  lateral 
incisors,  necessitating  an  operation  for  the  restoration  of  these  spaces 
and  anterior  development  of  the  arch  as  seen  in  the  cast  on  the  right 
of  Fig,  '716,  the  deciduous  laterals  immediately  erupting  upon  being 
released  from  imprisonment. 

Results  of  Extraction  of  Deciduous  Cuspids. — A  Class  I  case, 
in  which  the  lower  deciduous  cuspids  have  been  prematurely  ex- 
tracted, with  the  complete  loss  of  their  space  and  anterior  arrest  of 
development  in  consequence,  is  illustrated  in  Fig.  717. 

The  lower  incisors,  having  lost  their  support  in  the  cuspid  region, 
have  become  inclined  lingually,  and  the  upper  incisors  have  been 


THE  PROBLEM  OF  EXTRACTION. 


809 


Fig.  718. 


8lO  ORTHODONTIA. 

forced  back  against  the  lower  incisors  through  the  pressure  of  the 
lips  and  abnormal  function. 

The  treatment  of  this  case  was  undertaken  at  the  time  it  presented 
with  this  condition  of  occlusion,  and  both  arches  were  expanded, 
in  the  lower,  the  cuspid  spaces  being  regained,  as  shown  in  the  casts 
at  the  top  of  Fig.  718,  and  in  the  upper,  the  centrals  moved  forward, 
and  the  space  for  the  right  first  deciduous  molar  regained,  as  shown 
in  the  casts  in  the  lower  part  of  Fig.  718,  and  this  relationship  estab- 
lished through  proper  retention  until  the  eruption  of  the  permanent 
cuspids  and  bicuspids. 

A  very  noticeable  improvement  in  the  profile  through  this  treat- 
ment may  be  seen  in  the  central  portion  of  Fig.  718,  showing  that  the 
harmony  of  the  facial  lines  is  effected  by  such  apparently  slight  arrest 


Fig.  719. 

of  development  as  is  caused  by  the  loss  of  the  lower  deciduous  cuspids 
and  an  upper  deciduous  molar. 

Result  of  Extraction  of  Deciduous  Molars. — The  model  on 
the  left  in  Fig.  719  exhibits  a  case  in  which  the  lower  deciduous  molar 
was  prematurely  extracted,  the  subsequent  closing  up  of  its  space,  and 
arrested  anterior  development  of  the  lower  arch,  with  the  dropping 
lingually  of  the  upper  incisors  in  an  attempt  on  the  part  of  Nature  to 
obtain  a  contact  occlusion  with  the  lower  incisors.  The  model  on 
the  right  illustrates  the  case  after  the  space  has  been  regained 
for  the  extracted  molar,  the  arches  harmonized  anteriorly  in  occlu- 
sion, and  a  band  and  bar  retention  attached  from  cuspid  to  first 
molar  in  the  lower  arch,  pending  the  eruption  of  the  permanent 
bicuspids. 

The  loss  by  extraction  of  any  of  the  deciduous  teeth  has  a  similar 


THE  PROBLEM  OF  EXTRACTION.  8ll 

destructive  effect  upon  the  occlusion,  the  difference  being  only  in 
degree. 

Evil  Effects  of  Extraction  of  Permanent  Teeth.— In  the  loss 
of  teeth  by  extraction  from  the  second  dentition,  somewhat  similar 
effects  upon  the  dental  arches  are  observed  as  those  produced  by 
extraction  or  premature  loss  of  the  deciduous  teeth. 

Successively,  the  results  of  extraction  of  one  or  more  of  the  perma- 
nent teeth  are  the  destruction  of  the  integrity  of  the  dental  arches,  the 
destruction  of  occlusion  and  articulation,  and  finally  the  marring  of 
the  facial  lines. 

The  extent  of  the  deformity  is  usually  proportionate  to  the  degree 
of  the  extraction,  every  additional  tooth  lost  causing  just  that  much 
more  aggravation  of  conditions  and  change  to  the  abnormal. 

Relative  Value  of  First  Permanent  Molars. — In  view  of  the 
prevalency  of  the  extraction  of  the  first  molars  it  may  be  well  to  con- 


FiG.  720. 

sider  first  their  relative  value  and  then  the  result  of  their  extraction  from 
the  arch.  Some  of  the  more  important  reasons  for  their  preservation 
in  the  arch  are  as  follows: 

1.  They  are  the  first  of  the  permanent  molar  teeth  to  erupt, 
and  during  the  period  of  shedding  of  the  temporary  dentition,  afford 
the  broadest  and  best  masticating  surfaces  in  the  mouth. 

2.  By  reason  of  their  great  size  and  strength,  they  are  the  only 
teeth  that  can  serve  as  a  means  of  preserving  the  normal  relationship 
between  the  dental  arches,  and  consequently  the  symmetry  of  the 
face,  at  a  time  when  no  other  of  the  permanent  teeth,  except  the  in- 
cisors, are  erupted  to  occlusion. 

3.  Their  presence  is  an  aid  in  the  forward  development  of  the 
mandible. 


8l2 


ORTHODONTIA. 


4.  Statistics  comparing  the  relative  frequency  of  caries  in  the 
first  and  second  molars  prove  the  second  molar  more  often  carious 
than  the  first. 

5.  The  first  molar,  on  the  average,  is  a  better  constructed  tooth 
than  either  the  second  or  the  third  molar. 

6.  Its  extraction  is  the  cause  of  a  large  percentage  of  cases  of 
malocclusion,  and  consequent  facial  inharmony. 

Results  of  Extraction  of  First  Permanent  Molar. — The  history 
of  the  case  of  malocclusion  in  Fig.  720  dates  its  inception  to  the  time 
of  the  extraction  of  the  lower  right  first  permanent  molar,  and  the  series 
of  intricate  changes  in  occlusion  to  the  abnormal  are  commonly 
observed. 

The  model  on  the  right  of  the  cut  represents  the  left  side  of  the 
case  in  occlusion,  exhibiting  normal  cusp  relationship  of  upper  and 
lower  teeth  as  far  forward  as  the  cuspid. 


Fig.  721. 


The  model  on  the  left  illustrates  the  destruction  of  occlusion  and 
the  shortening  of  the  right  lateral  half  of  the  dental  arch  as  a  result 
of  the  extraction  of  the  first  molar. 

To  the  student  of  occlusion,  the  changes  in  occlusal  relations  after  the 
loss  of  the  first  permanent  molar  are  more  or  less  familiar,  and  it 
is  comparatively  easy  to  follow  the  consecutive  stages  whereby  the 
ruination  of  otherwise  beautiful  dental  arches  has  been  accomplished. 

Consequent  upon  the  loss  of  the  first  molar  in  this  case,  ensued 
not  only  the  tipping  mesially  of  the  second  molar,  but  also  the  drift- 
ing distally  of  the  second  bicuspid  into  the  space,  followed  by  the 
distal  movement  of  the  first  bicuspid,  the  cuspid  and  incisors,  and 
the  contraction  of  the  whole  arch. 


THE  PROBLEM  OF  EXTRACTION.  813 

The  effect  of  this  contraction  upon  the  upper  arch  is  noticeable 
in  the  lingual  positions  of  the  incisors,  and  the  torsion  of  the  right 
lateral  incisor. 

The  closing  together  of  the  teeth  in  occlusion  tends  to  force  the 
lower  right  second  molar  still  farther  mesially,  and  to  draw  the  right 
lateral  half  of  the  lower  arch  distally  to  a  considerable  extent. 

The  occlusal  views  of  the  upper  and  lower  arches  in  this  case  in 
Fig.  721,  illustrate  from  this  aspect,  the  mutilated  arches,  both  being 
contracted  and  the  upper  arch  flattened  in  the  incisor  region,  produc- 
ing a  similar  effect  in  the  facial  profile,  as  a  consequence. 

The  author  has  observed  a  patient  with  a  similar  case  of  maloc- 
clusion, who  was  on  the  verge  of  nervous  collapse  as  a  result  of  suck 


Fig.  722. 

changes  in  occlusion  as  to  make  mastication  painful  and  almost  im- 
possible. 

Result  of  Extraction  of  Second  Bicuspids. — A  variation  from 
these  changes  in  occlusion  as  a  result  of  the  extraction  of  a  lower  second 
bicuspid  is  observed  in  Fig.  722. 

Although  not  revealed  by  the  picture,  the  second  bicuspid  on  the 
right  side  of  the  lower  arch  was  also  extracted  so  that  the  change  in 
occlusion  was  comparatively  uniform  bilaterally. 

The  loss  of  these  teeth  has  caused  an  apparent  protrusion  of  the 
upper  arch  in  Fig.  722  as  a  result  of  the  perversion  of  function  of  the 
occlusal  planes  and  also  of  the  lips,  the  lower  lip  tending  to  roll  up  under 
the  upper  incisors  and  force  them  still  farther  outward. 

The  first  and  second  molars  in  occlusion  have  retained  the  normal 
mesio-distal  relationship  of  the  arches,  and  the  contraction  of  the 


8 14  ORTHODONTIA. 

lower  arch  has  been  entirely  anterior  to  the  first  molars,  the  second 
bicuspid  spaces  being  almost  entirely  closed. 

Complications  in  Treatment  after  Extraction  of  Teeth. — 
The  treatment  of  cases  of  malocclusion  caused,  or  mutilated,  by  ex- 


FiG.  723. 

traction  of  the  permanent  teeth,  is  necessarily  much  more  complicated 
than  if  the  full  complement  of  teeth  were  present,  so  that  complete 
arch  restorations  as  well  as  occlusal  relations  might  be  established. 

As  a  rule,  it  is  imperative  that  all  spaces  of  teeth  which  have  been 
lost  through  extraction  should  be  restored  and  artificial  substitutes 


Fig.  724. 

inserted  in  order  to  secure  harmony  in  occlusion  between  the  dental 
arches. 

In  the  cast  on  the  left  of  Fig.  723,  it  will  be  noticed  that  the  lower 
right  lateral  incisor  is  missing,  it  having  been  extracted  for  the  pur- 


THE  PROBLEM  OF  EXTRACTION,  815 

pose  of  "regulating"  on  account  of  its  having  been  located  in  lingual 
occlusion. 

In  the  restoration  of  this  arch  to  normal  size,  the  space  for  the 
right  lateral  was  regained,  as  shown  in  the  cast  on  the  right  of  Fig. 
723.  How  much  more  scientific  it  would  have  been  to  have  enlarged 
this  arch  to  this  extent  when  the  case  first  presented  with  the  lateral 
in  lingual  occlusion  and  to  have  restored  it  to  its  normal  position  in 


FiG-  725.     {Gough.) 

the  arch.  Here,  indeed,  is  the  clue  to  the  proper  solution  of  the  case 
and  illustrates,  in  a  nutshell,  the  impropriety  of  extraction  either  "to 
make  room"  or  correct  alignment. 

The  before  and  after  treatment  models  of  the  case  viewed  from  the 
front  in  Fig.  724  illustrate  the  necessity  of  regaining  the  space  for  the 
lateral  incisor  and  providing  an  artificial  substitute  in  order  to  restore 
the  normal  relations  of  occlusion. 

If  the  upper  arch  only  had  been  restored  to  its  normal  size  and 


8i6 


ORTHODONTIA. 


shape,  it  would  have  been  larger  than  the  lower  by  the  width  of  the 
missing  lower  lateral  incisor. 

The  illustration  of  a  few  practical  cases  in  pairs,  of  the  same  class, 
one  of  the  pairs  having  been  treated  by  extracting,  the  other  by  restor- 
ation of  normal  occlusion,  may  serve,  by  comparison,  to  show  the 
relative  value  of  the  two  methods  of  treatment. 

Fig.  725  exhibits  a  Class  I  case  in  which  the  dentist,  who  originally 
had  it  in  charge,  before  referring  it  to  the  orthodontist,  thought  it  neces- 
sary to  extract  the  upper  first  bicuspid  on  the  left  side  in  order  to  "  make 
room"  for  the  eruption  of  the  left  upper  cuspid  which  was  formerly  in  a 
position  similar  to  that  of  the  right  cuspid  seen  in  labial  occlusion  in  the 
model  on  the  left  of  the  cut. 


Fig.  726. 

The  operation  of  extraction  was  performed  as  indicated,  the  upper 
left  cuspid  erupting  into  the  space,  partially,  but  so  incompletely 
filling  it  that  the  patient  was  unwilling  to  have  the  same  thing  done 
upon  the  right  side  of  the  arch. 

On  examination  of  the  occlusal  view  of  the  upper  and  lower  casts 
in  the  same  cut,  it  will  be  observed  that  the  lower  arch  is  contracted 
anteriorly,  the  cuspids  being  in  torso-occlusion,  and  if  an  operation 
for  expansion  of  both  arches  had  been  performed,  normal  occlusion 
could  have  been  obtained. 

Fig.  726  illustrates  a  precisely  similar  case,  both  as  to  etiology  and 
diagnosis,  except  that  the  malocclusion  is  limited  to  the  left  lateral  half 
of  the  arches. 

The  prognosis  in  cases  of  this  kind  is  always  favorable  to  treat- 


THE   PROBLEM  OE   EXTEACTION. 


817 


ment  without  extraction,  and  the  diagnosis  assures  such  splendid 
results  as  are  shown  in  the  after  treatment  model  on  the  right  of 
Fig.  726,  the  arches  being  restored  to  normal  size  and  shape,  and 
normal  occlusal  relations  being  established. 


Fig.  727. 

Fig,  727  exhibits  a  somewhat  more  severe  case  than  the  one  just 
described,  and  it  might  have  been  governed  by  the  same  laws  in  its 
treatment  if  thev  had  been  understood. 


Fig.  728. 

Two  mistakes  were  made  in  the  treatment  of  this  case,  however, 
one  by  the  extraction  of  the  upper  second  bicuspid,  the  other  the 
neglect  of  the  slight  irregularity  in  the  lower  in  the  treatment  of  the 
case.     The  after  treatment  model  on  the  right  shows  alignment  to  a 

52 


8i8 


ORTHODONTIA. 


certain  degree  but  it  will  be  noticed  that  the  arch  is  still  crowded,  and 
that  the  possibility  of  harmonizing  the  arches  and  restoring  occlusion  is 
forever  lost.  All  that  was  needed  was  the  regaining  of  some  lost  space 
in  the  lower  arch  and  the  harmonizing  of  the  upper  arch  to  it,  saving 
all  of  the  teeth. 

Fig.  728  illustrates  a  similar  case  in  which  the  ideal  has  been  attained 
in  the  restoration  of  normal  occlusion  without  extraction,  each  occlusal 
plane  having  been  moved  into  its  correct  relationship  with  its  antago- 
nist of  the  opposite  arch,  and  the  production  of  a  harmonious 
result  which  is  truly  beautiful.  These  results  were  obtained  some 
fifteen  years  ago  when  the  principles  of  occlusion  were  much  less 
known  than  now. 


Fig.  729. 

Coming  now  to  another  class  of  deformities  in  which  extraction 
of  one  or  more  of  the  bicuspids  has  been  advised  as  of  value  in  the 
reductions  of  protrusions  such  as  is  here  illustrated,  Fig.  729,  let  us 
note  in  the  case  the  results  of  such  extraction  upon  the  arch.  The  first 
bicuspid  was  extracted  and  the  anterior  teeth  drawn  distally  until 
the  space  of  the  extracted  tooth  was  closed,  a  very  common  operation 
extant  among  the  profession  for  the  correction  of  this  deformity.  The 
model  of  the  completed  case  on  the  right  exhibits  no  such  harmony  of 
contour  as  the  models  of  the  completed  cases  which  are  illustrated 
under  the  treatment  of  the  first  division  of  Class  II.  The  curves 
are    not    graceful,    the   mutual   support   of  the   full  complement  of 


THE  PROBLEM  OF  EXTRACTION.  819 

teeth  has  been  lost,  and  a  lame  and  crippled  appearance  is  distinctly 
noticeable. 

In  the  majority  of  cases  in  orthodontia,  extraction  of  the  teeth 
is  not  indicated,  in  fact,  an  almost  iron  clad  rule  has  been  established 
by  some  specialists  operating  from  the  basis  of  occlusion,  condemning 
extraction  in  all  cases. 

While  this  rule  is  a  safe  one  to  follow  in  the  majority  of  cases,  to 
attempt  to  practise  it  in  every  case  would  be  entirely  unwise,  as  there 
are  cases  in  which  it  is  not  only  impossible  to  restore  normal  occlu- 
sion, but  in  which  extraction  is  indicated  in  order  to  obtain  any  sort  of 
harmony  of  the  occlusion. 

These  exceptions  do  not  necessarily  lower  the  standard  of  perfec- 
tion which  the  restoration  of  the  normal  or  ideal  in  every  case  might 
imply,  since  their  very  existence  and  the  difficulty  of  their  diagno- 
sis should,  in  the  nature  of  things,  compel  the  operator  to  use  his 
best  judgment  and  follow  a  safe  rule. 

In  what  cases,  then,  is  extraction  advisable  ?  The  answer  to  this 
question  is  the  knotty  part  of  the  problem,  for  although  we  are  cer- 
tain of  the  advisability  of  the  procedure  in  some  cases,  to  lay  down  a 
set  rule  for  such  cases  would  militate  against  the  best  results  which 
might  be  obtained  without  extraction,  for  in  two  identically  similar 
cases,  extraction  may  be  found  necessary  in  one,  while  in  the  other, 
the  restoration  of  the  ideal  in  occlusal  harmony  may  be  easily 
diagnosed  and  obtained. 

Exceptions  to  the  general  rule  of  occlusal  restoration  in  which 
it  is  advisable  to  extract  does  not  give  license  to  extract  promiscuously, 
and  the  only  hesitation  which  the  author  feels  in  attempting  to  point 
out  these  exceptions  lies  in  the  possible  exaggeration  of  the  number  of 
cases  in  which  the  novice,  because  of  his  lack  of  experience,  and  the  un- 
scrupulous dentist,  because  of  his  indifference,  might  feel  justified  in  ex- 
tracting teeth  unnecessarily  because  of  any  loophole  which  the  knowledge 
of  an  exception  to  the  general  rule  of  non-extraction  might  give  them. 

But  in  the  publication  of  a  scientific  work  on  orthodontia,  which, 
to  be  scientific  and  most  helpful  to  the  general  practitioner,  should 
not  be  misleading,  the  obligation  laid  upon  the  author  is  so  great, 
that  to  attempt  to  encourage  the  attainment  of  impossible  results 
through  non-extraction  and  futile  attempts  at  occlusal  restoration, 
would  defeat  the  object  of  the  promulgation  of  the  truth  which  should  be 
paramount  in  the  building  up  of  any  science  which  tends  in  any  way  to 
benefit  the  human  race. 

It  might  be  correctly  stated  that  extraction  is  advisable  in  some 


820  ORTHODONTIA. 

few  cases  in  which  it  is  impossible  to  obtain  a  satisfactory  result 
after  an  intelligent  and  persistent  effort  in  following  out  the  laws  of 
occlusal  restoration. 

Or,  in  cases  of  monstrosities  of  tooth  dentition,  such  as  in  extreme 
hypertrophy  of  the  alveolar  processes,  where  restoration  of  normal 
occlusal  relations  would  only  exaggerate  the  deformity  and  increase 
the  inharmony  of  facial  contour. 

In  cases  already  mutilated  by  extraction,  in  which  it  is  not  advisable 
to  restore  normal  occlusion  by  regaining  all  spaces  lost  by  such  extrac- 
tion, it  may  be  necessary  to  extract  according  to  the  requirements 
which  are  peculiar  to  the  individual  case,  and  for  which  no  set  rule  may 
be  established. 

So  seldom  is  extraction  indicated  that  in  the  author's  practice, 
it  has  been  resorted  to  in  but  six  cases  in  fifteen  years,  and  a  similar 
record  will  be  found  in  the  practices  of  other  specialists  operating 
from  a  conservative  basis. 

In  these  cases,  the  advice  of  a  specialist  of  at  least  five  years'  ex- 
perience in  orthodontia  ought  to  be  sought,  in  order  that  an  error 
in  judgment  may  not  be  made  through  simple  lack  of  experience. 

PART   XIII. 
RETENTION. 

The  Object  of  Retention. — ^A  clear  perception  of  the  field  of  re- 
tention necessitates  a  proper  understanding  of  the  ultimate  purpose  of 
the  treatment  of  arrested  developmental  conditions  in  the  dental  arches, 
which  is  the  restoration  of  function,  through  the  stimulation  of  struc- 
tural development  in  the  maxillary  arches,  and  the  attainment  of 
the  normal  in  occlusion  and  articulation. 

It  will  be  inferred  from  this  statement  that  the  development  and 
restoration  of  the  normal  in  shape  and  size  of  the  individual  dental 
arch  is  the  primary,  and  the  attainment  of  normal  positions  of  inclined 
planes  of  antagonizing  cusps  of  occluding  teeth  the  secondary,  con- 
sideration.in  treatment,  these  two  phases  being  so  related,  however, 
that  the  consideration  of  the  one  without  the  other  would  be  incom- 
prehensive  of  the  scope  of  orthodontia. 

Necessity  for  Retention. — ^In  the  dental  malocclusions  of  the 
child  from  six  to  ten  years  of  age,  the  rapid  restoration  of  function 
through  orthodontic  treatment  is  so  aided  by  this  stimulation  to  normal 
growth  that  the  retention  of  these  cases  is  a  matter  of  a  few  weeks  or 
months  only,  except  in  cases  of  distal  occlusion  and  its  accompan)dng 


RETENTION.  82 1 

ack  of  vertical  development  of  the  dental  arches,  or  in  cases  of  infra- 
occlusion  in  the  incisor  region. 

Expanded  arches  of  these  early  undertaken  cases  need  to  be  retained 
only  until  the  eruption  of  permanent  incisors,  cuspids  or  bicuspids, 
according  to  the  age  treatment  is  begun.  Incisors  which  have  been 
rotated  during  or  soon  after  eruption  need  but  a  few  weeks'  retention 
before  the  rapidly  developing  alveolar  process  and  the  fibers  of  the 
peridental  membrane  accommodate  themselves  to  new  conditions  of 
resisting  tendencies  to  displace  these  teeth  from  their  new  positions  in 
normal  occlusion.  In  the  more  mature  cases,  the  resistive  qualities 
of  the  osseous  structures  in  which  the  teeth  are  implanted,  and  of  the 
fibrous  elastic  membranes  with  which  they  are  surrounded,  are  in 
evidence  until  long  after  treatment  is  completed,  and  unless  these 
reactive  forces  are  inhibited  for  varying  periods  after  the  completion  of 
treatment,  more  or  less  of  a  return  of  former  conditions  of  imperfec- 
tion of  form,  and  of  occlusal  relations  of  the  dental  arches  is  inevitable. 

Added  to  these  untoward  influences  the  possible  abnormal  habits  of 
mouth-breathing,  thumb-  and  lip-sucking,  and  the  abnormal  tension  of 
the  muscles  of  the  tongue,  lips  and  cheeks,  and  the  abnormal  influence 
of  inclined  cusp  planes  present  in  many  cases,  the  forces  which  tend 
to  resist  normal  development  and  function  may  be  considerable. 

Hence  it  is  that  retention  is  really  a  passive  or  at  least  a  less  active 
stage  of  treatment,  and  success  in  treatment  is  only  assured  when  reten- 
tion is  carefully  provided  for. 

Retention  may  he  defined  as  the  maintenance  of  such  development 
of  the  dental  arches  and  relations  of  occlusion  as  may  have  been  established 
through  treatment,  by  a  proper  antagonism  of  any  forces  which  may  in- 
terfere with  these  normal  structural  and  functional  conditions. 

The  establishment  of  mechanical  resistance  to  these  return  tend- 
encies through  appliances  attached  to  the  teeth  must  be  sufficient  so 
that  an  equilibrium  between  the  forces  of  reaction  and  the  applied 
resistance  is  obtained.  An  insufficiency  of  resistance  in  a  retaining 
appliance  would  result  in  a  partial  return  of  former  conditions. 

Retention,  then,  as  in  anchorage,  is  a  measure  of  resistance  values, 
the  proper  appreciation  of  which  is  essential  to  the  permanence  of 
results  obtained  in  treatment. 

Length  of  Retention. — Usually  the  retention  of  a  corrected  mal- 
occlusion is  a  matter  of  more  than  a  few  weeks  in  point  of  time,  many 
cases  requiring  months,  and  some  of  the  more  severe,  several  years  of 
fixation  in  order  to  overcome  the  resistance  of  the  fibers  of  the  peridental 
membrane,  and  the  tendency  of  the  arches  to  contract  or  assume  their 


822  ORTHODONTIA, 

original  forms  and  relationships  after  having  been  restored  to  a  normal 
condition  of  occlusion,  or  after  being  mechanically  developed  up  to  a 
physiological  limit. 

The  retention  of  the  deciduous  teeth  is  a  process  of  temporary 
fixation  for  the  development  of  the  arch  alone,  v^hlle  the  retention 
of  the  permanent  teeth  is  often  a  necessity  for  their  maintenance  in 
their  relative  positions  in  the  arch,  although  developmental  changes 
are  still  going  on. 

The  length  of  time  of  retention  of  the  arches  of  deciduous  teeth, 
at  the  most,  can  only  last  until  the  eruption  of  the  permanent  teeth, 
in  whole  or  in  part. 

Permanent  teeth,  which  have  been  moved  into  their  normal  lines  of 
occlusion  during  eruption  or  immediately  after,  need  retention  for 
a  far  shorter  time  than  if  they  have  been  confirmed  in  their  abnor- 
mal positions  for  some  time  before  being  corrected. 

It  is  a  well  known  fact  in  orthopedic  and  orthodontic  practice  thai 
the  rapidity  of  the  restorative  or  building  up  process  in  bony  tissues,  as 
after  setting  of  fractures,  is  proportionate  to  the  degree  of  fixation  of  the 
parts  during  the  period  immediately  following  the  corrective  operations. 

To  the  end,  therefore,  of  shortening  the  time  of  retention,  as  well 
as  obtaining  a  more  perfect  development  and  greater  strength  of  the 
tissues  surrounding  the  moved  teeth,  and  avoiding  the  possibility  of 
any  loss  from  contraction  of  arches  after  expansion  or  regaining  of 
spaces,  the  fixed  retaining  appliance,  with  cemented  bands,  is  gener- 
ally to  be  preferred  to  any  other. 

Retention  Classified. — Retention  may  be  classified  as  follows: 
Occlusal,  simple,  reciprocal,  intermaxillary,  and  occipital,  according  to 
the  quality  of  resistance  used  in  opposing  the  reactive  forces,  or  the  return 
tendencies. 

Of  especial  importance  is  the  influence  of  the  inclined  planes  of 
the  cusps  in  retention,  their  normal  function  ending  in  occlusion  and 
articulation,  to  preserve  the  integrity  of  the  arches. 

Occlusal  retention  is  the  maintenance  of  the  normal  occlusal  posi- 
tions of  the  teeth,  individually  or  collectively,  through  the  normal  functional 
influence  of  the  inclined  planes  of  the  cusps,  and  the  contributory  forces 
gained  through  restoration  of  arch  integrity. 

In  order  to  secure  the  harmonious  working  of  the  inclined  planes 
it  is  necessary  that  not  only  should  the  full  complement  of  teeth  be 
present,  preserving  individual  arch  integrity  by  proximate  contact, 
but  that  the  normal  size  and  shape  of  the  arches  be  restored,  which 
would  include  the  restoration  of  articulating  planes  and  compensating 


RETENTION.  823 

curves,  etc.  Experience  will  prove  that  articulating  planes  can  be  only 
approximately  obtained  in  the  correction  of  malocclusion,  so  compli- 
cated is  the  mechanism  of  articulation,  and  the  lack  of  development 
of  the  arches  in  malocclusion  so  disturbing  the  harmonious  working 
of  the  laws  of  articulation  that  accurate  arch  and  cusp  protection 
in  articular  movements  is  outside  the  range  of  possibility  of  treatment, 
except  in  special  cases. 

In  malocclusion  there  is  abnormal  function  of  occlusal  inclined 
planes  of  cusps,  often  deficient  respiratory  mechanism,  and  tongue  or  lip 
insufficiency,  and  abnormal  muscular  pressure,  which,  if  not  corrected 
will  still  continue  their  abnormal  influence  upon  the  arches  of  teeth. 

The  nearer  the  approach  to  normal  occlusion  and  articulation  in 
the  treatment  of  any  case  of  malocclusion,  the  less  need  will  there  be 
for  mechanical  retention  beyond  that  afforded  by  the  normal  action 
and  reaction  of  the  inclined  planes  of  the  cusps. 

It  must  be  remembered  however,  that  the  restoration  of  the 
normal  functions  of  occlusion  and  articulation  does  not  counteract 
the  tendency  of  the  fibers  of  the  peridental  membrane  and  the  alveolar 
process  to  assume  their  former  relations  of  abnormality,  except  to 
a  slight  degree,  otherwise  there  would  be  very  little  need  for  mechan- 
ical retention  of  teeth  and  arches. 

The  normal  relations  of  occlusal  inclined  planes  in  the  attainment 
of  normal  occlusion,  cannot  he  depended  upon  alone,  for  retention,  until 
after  varying  periods  of  fixed  retention  of  the  teeth  and  arches  with 
mechanical  appliances,  except  in  simple  and  special  cases. 

An  upper  incisor  tooth,  moved  from  lingual  to  normal  occlusion, 
if  there  is  sufficient  overbite,  will  be  retained  by  the  action  of  the  lingual 
incline  of  the  upper  incisor  upon  the  labial  incline  of  the  lower  incisor. 

The  same  effect  will  be  observed  where  there  is  sufficient  overbite 
in  any  of  the  upper  teeth  which  have  been  moved  into  their  line  of 
occlusion  from  lingual  occlusion  and  restored  to  the  normal  action 
of  the  inclined  planes. 

To  a  lesser  degree,  also,  the  restoration  of  upper  bicuspids  and 
molars  in  buccal  occlusion,  lower  incisors  and  cuspids  in  labial  occlusion, 
and  lower  bicuspids  in  lingual  or  buccal  occlusion,  will  be  retained  by 
the  restoration  of  the  normal  influence  of  their  inclined  planes  in 
occlusion. 

Infra-occlusion  of  the  teeth,  on  the  other  hand,  demands  long  and 
persistent  retention  of  corrected  occlusion. 

Also,  teeth  which  have  been  rotated,  unless  at  a  very  early  age,  as 


824  ORTHODONTIA. 

during  their  eruption,  will  need  retention  by  mechanical  appliances  for 
varying  periods  of  time. 

Again,  anterior  and  posterior  expansion  of  arches  will  usually  need 
retention  for  periods  of  time  varying  according  to  the  degree  or  extent  of 
the  expansion,  the  age  of  the  patient,  the  peculiarities  of  the  case,  etc. 

Extensive  cases  of  Classes  II  and  III,  will  always  demand  a  very 
persistent  mechanical  retention,  often  for  several  years. 

Simple  cases  of  Class  II,  especially  of  the  second  division,  and  its 
subdivision,  and  of  Class  III,  are  often  retained  by  normal  cusp  in- 
fluence alone,  as  far  as  the  mesio-distal  relations  of  occlusion  are 
concerned. 

Fig.  682  is  an  example  of  bilateral  distal  occlusion,  Class  II, 
Div.  2,  which  was  retained  in  its  mesio-distal  relations  entirely  by  the 
interdigitation  of  the  cusps  of  bicuspids  and  molars,  although  the  upper 
incisors  were  retained  by  bands  and  spurs  for  a  short  time. 

Auxiliary  Occlusal  Retention  is  the  maintenance  of  the  normal 
occlusal  relations  of  the  individual  teeth,  or  of  the  dental  arches  as  a  whole 
by  means  of  auxiliary  occluding  inclined  planes. 

Examples  of  auxiliary  occlusal  retention  are  seen  in  the  auxiliary  cusps 
on  cuspid  bands  for  retention,  the  lingual  inclined  planes  on  upper 
incisor  bands,  or  on  lingual  arches,  and  the  spur  and  plane  retention  of 
Class  II  and  Class  III. 

Simple  retention  is  the  antagonism  0}  the  forces  of  reaction  by  the 
resistance  of  one  or  more  teeth,  in  the  same  arch ,  which  afford  a  compara- 
tively stable  resistance  in  opposition  to  these  forces. 


Fig.  730. 

For  example,  in  Fig.  730,  A,  the  central  incisor  which  was  in  lingual 
occlusion  is  retained  in  position  by  cementing  upon  it  a  band  with 
labial  spur  extending  over  the  labial  surface  of  each  adjoining  tooth, 
as  shown  at  B  in  the  same  figure.  The  adjoining  teeth  may  have 
shared  in  a  general  expansive  movement  to  a  slight  degree,  but  would 
still  afford  a  comparatively  stable  resistance  for  retaining  the  lingual 
tendency  of  the  central  incisor  which  was  in  lingual  occlusion. 

A  torso-mesial  occlusion  of  the  one  central  may  be  retained 
by  the  cemented  band  and  lingual  spur  over  the  lingual  surface  of  the 
other  central  which  may,  or  may  not  have  been  moved  to  a  slight  ex- 


RETENTION. 


'25 


tent  labially  or  lingually.  An  absolutely  stable  resistance  in  single 
tooth  movements  is,  of  course,  to  be  preferred  for  retention  purposes. 

Reciprocal  retention  is  the  counterbalancing  oj  the  return  tendencies 
of  two  or  more  teeth  in  the  same  arch  or  in  opposite  arches  by  the  antago- 
nism or  opposition  oj  their  reactive  forces. 

Simple  reciprocal  retention  would  be  represented  by  the  antago- 
nism of  the  reactive  tendencies  of  two  teeth  which  have  been  moved  in 
opposite  directions,  as  illustrated  in  Fig.  731,  the  two  centrals  being 


Fig.  731. 

rotated  in  opposite  directions,  and  the  retention  consisting  of  two  bands 
soldered  together,  and  cemented  upon  the  centrals. 

Another  example  of  simple  reciprocal  retention  is  illustrated  in 
Fig.  732,  the  lateral  incisor  and  first  bicuspid  being  reciprocally  an- 
tagonized in  their  return  tendencies  by  the  band  and  spur  method. 

Compound  reciprocal  retention  would  be  represented  by  the  antago- 
nism of  the  tendencies  to  return  of  several  teeth  in  the  same  or 
opposite  arches. 


Fig.  732 

In  Figs.  733,  734  and  735  are  illustrated  various  methods  of  securing 
simple  and  reciprocal  retention.  For  example,  in  B,  Fig.  733.,  the 
rotating  tendency  of  the  central  incisor  may  be  antagonized  after  correc- 
tion by  simple  retention  by  means  of  labially  and  lingually  placed  spurs  on 
a  cemented  band  as  in  C,  Fig.  733.  In  D,  Fig.  733,  the  tendencies  of 
the  mesial  angles  of  the  two  centrals  to  rotate  in  opposite  directions  may 


826 


ORTHODONTIA. 


be  counteracted  by  simple  reciprocal  retention  as  in  E,  Fig.  733,  by  a  spur 
from  the  mesial  angle  of  one  central  band  to  the  other,  simple  retention 
would  be  here  represented  by  the  labial  and  lingual  spurs  extending 
from  the  central  bands  to  the  adjacent  laterals.  At  F,  Fig.  733,  is 
shown  a  variation  of  simple  retention  in  the  use  of  spurs  from  the  central 
bands  bent  over  a  lingual  arch,  as  suggested  by  Lourie. 

Fig.  734  exhibits  at  GH  and  KL  the  application  of  compound  recip- 
rocal retention  by  the  use  of  bands  and  spurs.     In  Fig.  735  compound 


F 

Fig.  733. 

reciprocal  retention  is  illustrated  in  the  use  of  spurs  from  the  central 
incisor  bands  attached  to  a  lingual  arch,  which  assists  in  retaining  the 
lateral  incisors  at  the  same  time. 

Intermaxillary  retention  may  be  compound  reciprocal  retention 
between  teeth  of  opposite  arches  when  properly  provided  for. 

In  the  retention  of  the  expanded  arch,  as  in  Fig.  739,  the  resistance 
of  one  lateral  half  is  pitted  against  that  of  the  other,  and  is  an  illustra- 
tion of  compound  reciprocal  retention. 


G 


H 


K 


Intermaxillary  retention  consists  of  the  continuation  of  the  use  of 
intermaxillary  force  in  cases  of  mesial  or  distal  shifting  of  occlusion  in 
such  a  manner  that  a  reciprocation  of  force  and  resistance  is  established 


RETENTION.  827 

which   is   capable   of   the   retention   of    the    mesio-distal    chattges    in 
occlusion. 

In  adult  cases  or  in  "mixed  dentures"  of  Class  II  or  III, 
the  necessity  for  the  use  of  the  intermaxillary  force  for  a  considerable 
time  after  treatment,  in  order  to  retain  the  normal  mesio-distal  re- 
lations of  the  dental  arches,  or  the  restored  occlusal  planes,  is  evident 
to  the  experienced  orthodontist.  This  form  of  retention  is  especially 
applicable  in  cases  of  the  first  division  of  Class  II  and  in  Class  III. 
Intermaxillary  retention  is  also  of  great  value  in  upper  protrusions  of 
Class  I. 

^Occipital  retention  consists  of  a  continuation  of  the  wearing  oj 
the  headgear  and  traction  bar  or  chin  cap  for  counteracting  the  resistance 
offered  by  the  lower  dental  arch  or  the  mandible  after  treatment  of  mesial 
occlusion  or  of  infra-occlusion  with  occipital  force  and  anchorage. 

Occipital  retention  is  seldom  used  except  in  cases  in  which  the  chin 
cap  has  been  used  in  connection  with  it  for  correction  of  severe  cases  of 


M 

N 


Fig.  735. 


mesial  occlusion  or  of  infra-occlusion  of  the  anterior  teeth.  After  the 
use  of  the  headgear  for  treatment  in  Class  II  or  Class  III,  intermaxillary 
retention  is  usually  substituted  as  being  sufficient  to  retain  the  mesio- 
distal  changes  in  occlusion. 

Field  of  Retention. — i .  In  the  simpler  cases  of  malocclusion  where 
the  arches  are  in  normal  mesio-distal  relation,  the  dental  arches  being 
fully  developed,  and  the  overbite  normal,  the  retention  of  corrected 
slight  malpositions  of  individual  teeth  is  all  that  is  necessary.  The 
usual  case,  however,  presents  with  a  complication  of  malocclusions, 
necessitating  retention  of  expanded  arches  and  individual  tooth  malpo- 
sitions, often  with  infra-occlusion  or  supra-occlusion,  requiring  a  change 
in  the  occlusal  plane  and  its  retention,  and  occasionally  still  further  com- 
plicated by  a  distal  or  mesial  malocclusion  requiring  particular  methods 
of  retention. 


828  ORTHODONTIA. 

In  general,  then,  the  field  of  retention  may  be  divided  as  follows:  i. 
The  retention  of  corrected  malocclusions  of  individual  teeth;  2,  reten- 
tion of  expanded  arches;  3,  retention  of  changes  in  the  occlusal  plane; 
4,  retention  of  mesial  or  distal  changes  in  occlusion. 

Retention  of  Malocclusion  of  Individual  Teeth. — In  the  reten- 
tion of  malocclusions  of  individual  teeth,  the  age  of  the  patient  and  the 
length  of  time  the  teeth  have  been  in  malocclusion  must  be  considered. 
Incisors  moved  from  lingual  to  normal  labial  positions  need  no  reten- 
tion other  than  the  occlusal  retention  of  the  cusps.  Occlusal  retention  may 
also  be  depended  on  for  the  retention  of  cuspids,  bicuspids  and  molars 
moved  from  lingual  occlusion  to  normal  if  the  malocclusion  is  not  one  of 
loner  standing.  Teeth  which  have  been  erupted  but  a  few  months^  such 
as  incisors  in  torsal  occlusion,  need  but  a  few  weeks'  retention. 

In  more  advanced  cases  in  which  the  permanent  teeth  are  all  erupted, 
':orrected  lingual  positions  of  incisors  in  Class  I  need  only  natural 
occlusal  retention.  Corrected  torsal  positions  of  incisors  in  these  cases, 
however,  need  a  persistent  simple  or  reciprocal  retention  as  in  Figs.  731 
and  733  for  at  least  one  year. 


FiG.  736. 

Retention  after  Bodily  Movement  of  Teeth.— Again  the  reten- 
tion of  teeth  which  have  been  moved  bodily  must  be  of  a  different  nature 
than  that  of  teeth  moved  by  inclination  movement.  At  the  present  writ- 
ing the  best  method  of  retention  after  bodily  movement  of  teeth  is  a 
continuation  of  the  wearing  of  part  of  or  all  of  the  appliance  which  was 
used  to  effect  the  bodily  movement. 

In  some  cases  the  author  has  used  a  portion  of  the  .30-in.  arch  wire 
with  vertical  pins  locking  in  tubes  as  in  Fig.  736  to  retain  the  positions 
of  the  four  incisors  which  have  been  moved  bodily.  Various  combina- 
tions of  this  nature  will  suggest  themselves  to  the  operator. 

Retention  of  the  Expanded  Arch.— The  age  at  which  treatment 
is  begun,  and  the  number  of  permanent  teeth  erupted,  will  necessarily 
require  a  variation  of  forms  of  retention  according  to  the  demands  of 
the  individual  case. 

If  uniform  development  of  the  dental  arch  has  occurred  during 
treatment,  that  is,  the  arch  being  expanded  in  the  molar  as  well  as  the 


RETENTION!  829 

cuspid  region,  the  retention  will  have  to  be  so  applied  that  this  expan- 
sion will  be  uniformly  retained. 

In  many  cases,  however,  only  the  anterior  portion  of  the  dental 
arch  is  developed,  hence,  the  retention  of  the  entire  dental  arch  is 
unnecessary. 

The  earliest  indication  for  retention  in  the  deciduous  arch  is  after 
a  certain  amount  of  expansion  of  the  anterior  portion  of  this  arch  for 
securing  development  enough  for  the  eruption  of  the  incisors  and  cus- 
pids, and  possibly  the  bicuspids. 

The  need  for  a  fixed  retention  of  a  part  of  the  deciduous  arch,  during 
a  varying  period  of  natural  development  and  including  the  eruption  of 
some  of  the  permanent  teeth  is  therefore  apparent. 


Fig.  737. 

Retention  of  Anterior  Part  of  Developing  Arch. — An  appliance 
which  will  efifectiially  retain  the  anterior  part  of  the  arch  during  the 
developing  period  and  which  is  attached  entirely  to  the  deciduous  teeth, 
is  shown  in  Fig.  737,  being  the  retention  of  the  anterior  part  of  the  ex- 
panded arch  shown  in  Fig.  620, 

The  deciduous  cuspids  are  banded  and  connected  by  a  lingual  wire 
of  18  or  19  gauge,  B.  &  S.,  and  short  spurs  are  extended  distally  from 
the  lingual  surface  of  the  cuspid  bands  upon  the  lingual  surface  of  the 
deciduous  molars.  A  great  amount  of  strength  in  a  retaining  appliance 
attached  to  the  deciduous  teeth  is  never  necessary  because  of  the  slight 
resistance  they  oflFer  to  the  action  of  force  appliances  in  their  movement, 
due  to  their  small  short  roots,  and  the  cartilaginous  nature  of  the  al- 
veolar process. 


830 


ORTHODONTIA. 


If  more  development  of  the  anterior  portion  of  the  arch  is  re- 
quired after  the  expansion  has  been  carried  on  as  far  as  possible,  the 
retainer  may  be  constructed  as  in  Fig.  738,  in  which  the  lingual  wire 

slips  into  short  tubes  soldered  to  the 
cuspid  bands,  and  by  pinching  with  the 
wire  stretching  pliers,  as  suggested  by 
Angle,  the  arch  may  be  still  further 
expanded  in  this  region  during  the  period 
of  retention.  The  lingual  wire  in  this 
case  should  be  constructed  of  platinized 
gold  sufficiently  soft  to  be  easily  stretched 
in  this  manner  without  breaking. 
Retention  of  the  Entire  Deciduous  Arch. — In  case  that  the 
deciduous  arch  has  been  uniformly  developed  by  expanding  anteriorly 
and  posteriorly,  an  immediate  need  exists  for  the  retention  of  all  the 
increased  width  and  length  of  the  arch  which  has  been  gained  in  the 
treatment. 


Fig.  738. 


Fig.    739. 

To  illustrate,  the  upper  arch  in  Fig.  623,  although  the  permanent 
central  incisors  and  first  molars  are  present,  is  still  the  same  in 
width    as  the   deciduous  arch,    and    in    development    is   still  a  de- 


RETENTION. 


831 


ciduous  arch.  The  central  incisors  being  .39  inch  wide,  require, 
according  to  the  Hawley  measurements,  an  arch  considerably  larger 
than  the  average. 

Having  been  expanded  during  a  period  when  the  deciduous  teeth 
present  were  comparatively  firm  in  their  attachments,  the  crowns 
of  the  permanent  teeth  being  moved 
laterally  through  their  envelopment  by 
the  roots  of  the  deciduous  molars,  the 
indicated  retention  in  the  case  is  a 
fixed  retention  of  the  entire  deciduous 
arch  until  such  time  as  the  natural 
developmental  processes  have  been 
completed  so  that  the  eruption  of  the 
remaining  permanent  teeth  may  take 
place  in  a  sufficiently  enlarged  arch. 

According  to  these  indications,  the 
retention  exhibited  in  Fig.  739  was  ad- 
justed, bands  of  iridio-platinum  being  fitted  to  the  deciduous  cuspids 
and  second  molars,  and  connected  by  a  lingual  retaining  wire  of  19 
gauge,  B.  &  S.,  iridio-platinum,  soldered  to  their  lingual  surfaces,  and 
extending  across  the  lingual  surfaces  of  the  first  permanent  molars. 

In  order  to  secure  a  more  accurate  fit,  the  lingual  wire  was  adjusted 


Fig.  740. 


Fig. 


741. 


and  soldered  to  the  bands  upon  the  plaster  cast,  the  bands  having  been 
removed  with  the  impression.  The  central  incisors  were  retained 
with  two  iridio-platinum  bands  united  with  solder,  and  cemented  in 
position.  A  slight  lateral  spring  may  be  given  to  the  lingual  retain- 
ing wire  to  assist  in  further  stimulus  to  lateral  development  of  the  arch 
if  necessary. 


832 


ORTHODONTIA. 


Retention  of  Anterior  Portion  of  Permanent  Arch. — Where  the 
permanent  arch  has  been  expanded  anteriorly,  it  is  essential  that  the 
increased  width  of  the  arch  should  be  retained  for  some  time,  so  as  to 
allow  the  development  of  the  alveolar  process  and  the  overcoming  of  the 
forces  of  reaction.  For  example,  if  the  arch  has  been  expanded  ante- 
riorly to  allow  the  centrals  or  laterals  to  be  rotated,  etc.,  the  retention  of 
these  individual  teeth  in  their  lines  of  occlusion  is  not  sufficient  in  most 
cases,  as  the  reactive  force  in  the  contractive  tendency  of  the  arch  will 
soon  cause  a  malocclusion  to  appear,  such  as  the  overlapping  or 
torsion  of  one  or  more  of  the  incisors. 


Fig.  742. 

It  is  advisable,  therefore,  to  always  retain  the  arc  of  the  six  anterior 
teeth  by  means  of  a  fixed  retaining  appliance  which  will  hold  the  width, 
gained  between  the  cuspids,  such  as  is  shown  in  Fig.  740,  adding  a 
lingual  spur  to  the  first  bicuspids  when  they  have  also  been  included  in 
the  lateral  expansion. 

Fig.  741  illustrates  the  expansion  and  retention  of  the  anterior  por- 
tion of  an  upper  arch,  in  which  space  was  made  for  the  eruption  of  the 
cuspids.  Bands  were  cemented  upon  both  of  the  first  bicuspids,  these 
bands  having  previously  been  united  with  the  strong  18  gauge  bar  of  plati- 
nized gold  extending  along  the  lingual  surfaces  of  the  incisors,  and 
having  spurs  of  21  gauge  gold  wire  bent  around  the  distal  angles  of  the 
lateral  incisors  to  the  labial  surfaces  to  hold  the  four  incisors  intact. 


RETENTION.  833 

This  appliance  is  as  simple  and  esthetic  as  can  possibly  be  con- 
structed for  a  case  of  this  character,  and  it  might  well  be  used  as  a 
standard  retention  for  similar  cases  in  which  no  rotation  of  teeth  is 
necessary  in  the  incisor  region. 

The  Lingual  Arch  Retainer. — The  use  of  the  Ungual  arch  re- 
tainer, as  suggested  by  Lourie,  invites  many  possibilities  of  prac- 
tical and  esthetic  retention  of  the  dental  arches,  because  of  its  efficiency 
and  inconspicuousness. 

Consisting,  as  shown  in  Fig.  742,  of  a  gold  and  platinum  or  an  iridio- 
platinum  wire  closely  adapted  to  the  lingual  surfaces  of  the  incisors, 
cuspids,  and  bicuspids,  and  attached  distally  to  the  ends  of  the  lingual 
screws  or  lingual  surfaces  of  molar  or  bicuspid  clamp  bands,  or  to  the 
lingual  surface  of  plain  bands,  it  is  correct  in  principle  since  it  provides 
for  complete  retention  of  the  entire  dental  arch  after  general  expansion, 


Fig.  743. 

at  the  same  time  providing  for  such  retention  of  the  individual  teeth 
as  may  be  necessary. 

The  retention  of  teeth  which  have  been  moved  labially  or  lingually, 
extruded  or  intruded,  may  be  accomplished  with  this  method  by  at- 
taching hooks  to  the  lingual  surfaces  of  individual  bands  upon  the 
teeth,  and  bending  these  hooks  above  or  below  the  lingual  arch,  and 
in  such  positions  as  will  tend  to  overcome  the  particular  resistance 
required.  The  principle  of  the  lingual  arch  with  lingual  hooks  or 
spurs  attached  is  shown  in  Fig.  735. 

In  Fig.  742  its  use  in  retaining  the  extrusion  of  the  incisors  in  a 
former  case  of  open  bite  malocclusion  is  effective,  especially  with  the 
spurs  over  the  occlusal  surfaces  of  the  deciduous  molars,  enlisting  their 
resistance  in  supporting  the  lingual  arch  in  position  which  in  this 
instance  is  attached  to  clamp  bands  upon  the  deciduous  molars. 

In  Fig.  743  the  lingual  arch  presents  a  feature  of  additional  value 
53 


834 


ORTHODONTIA. 


in  its  prevention  of  the  tipping  or  rotation  of  the  teeth  which  sup- 
port the  buccal  spurs  for  retention  of  the  mesio-distal  relations  of 
the  arches. 

Retention  of  Entire  Permanent  Arch. — After  expansion  of  the 
permanent  arch  laterally  and  anteriorly,  a  fixed  retaining  appliance 
which  will  hold  the  form  and  size  of  the  arch  may  be  constructed  as 
shown  in  Fig.  743,  the  cuspids  and  first  molars  being  banded  and  con- 


FiG.  744. 

nected  with  a  lingual  wire  which  supports  the  intervening  teeth.  It 
is  advisable  to  construct  this  retaining  appliance  and  fit  it  to  the  teeth 
temporarily,  allowing  the  teeth  to  settle  somewhat,  when  the  appliance 
may  be  permanently  fitted  and  adjusted.  Teeth  which  have  been 
rotated  should  be  banded,  and  either  retained  by  labial  and  lingual 
spurs  upon  the  bands  or  by  some  attachment  of  the  bands  to  the 


Fig.  745. 

lingual  wire  to  counteract  their  return  tendency.  Whereas,  in  many  of 
the  simpler  cases  of  arch  expansion  this  form  of  retention  is  most 
excellent,  yet  it  is  somewhat  faulty  in  construction  for  those  cases  in 
which  the  cuspids  have  been  in  labial  occlusion,  similar  to  the  positions 
shown  in  Fig.  744,  for  with  the  cuspids  banded  and  supported  by  the 
lingual  wire,  they  are  held  rigidly  forward,  while  the  incisors,  having 


RETENTION.  835 

some  freedom,  settle  back  sufficiently  to  allow  the  cuspids  to  appear 
somewhat  in  labial  occlusion. 

In  order  to  obviate  this  difficulty,  the  author  has  constructed  a 
retaining  appliance  for  these  cases  upon  slightly  dififerent  lines,  as 
shown  in  Fig.  745.  The  lingual  wire  is  attached  to  bands  upon  the 
lateral  incisors  and  first  molars,  spurs  extending  distally  over  the 
labial  surfaces  of  the  cuspids,  effectually  retaining  them  in  position* 
and  allowing  them  to  settle  into  their  positions  even  more  perfectly.  Ini 
some  of  the  simpler  cases  in  which  the  cuspids  are  not  in  labial  occlusion^ 
the  lingual  arch  may  extend  from  one  first  molar  to  the  other  with- 
out being  attached  to  incisor  or  cuspid  bands. 

A  very  ingenious  and  efficient  retaining  appliance,  designed  by  H. 
A.  Baker  for  retention  of  the  entire  arch  is  illustrated  in  Fig.  746. 

In  effect,  it  is  a  lingual  arch,  KL,  of  clasp  wire,  17  gauge  B.  &  S.^ 
closely  adapted  to  the  lingual  surfaces  of  the  incisors,  cuspids,  and 


Fig.  746. 

bicuspids,  soldered  anteriorly  to  the  lingual  surfaces  of  gold  bands 
upon  the  cuspids,  with  its  distal  ends  engaging  in  rings  upon  the  lin- 
gual surfaces  of  gold  bands  upon  the  molar  teeth. 

The  labial  wire,  F,  extending  from  one  cuspid  band  to  the  other,  is 
designed  to  retain  the  incisors  from  a  return  to  positions  of  torsal 
or  other  malocclusion. 

For  greater  accuracy  of  adaptation,  this  appliance  is  preferably 
made  upon  a  cast,  the  four  bands  having  been  previously  constructed 
upon  the  natural  teeth,  and  an  impression  taken  of  the  arch  with  them 
in  position. 

The  molar  bands,  M  and  N,  are  first  cemented  into  place,  and  then, 
after  filling  the  cuspid  bands  with  cement,  the  distal  arms,  K  and  L,  are 
slipped  into  the  lingual  rings  on  the  molar  bands,  and  the  anterior 


836  ORTHODONTIA. 

portion  of  the  appliance  forced  into  position  upon  the  anterior  teeth, 
there  being  enough  play  in  the  lingual  rings  upon  the  molar  bands  for 
this  downward  movement  of  the  appliance. 

Retention  of  Changes  in  the  Occlusal  Plane. — ^The  changes  in 
the  occlusal  plane  necessitating  retention  are  usually  those  demanded 
after  treatment  of  infra-  and  supra-occlusion. 

Retention  of  Infra-occlusion  of  Incisors  and  Cuspids. — ^A  continuation 
of  the  use  of  the  operative  appliances  after  correction  of  infra-occlusion 
of  the  incisors  and  cuspids  is  often  the  only  practical  means  of  affecting 
their  retention.  For  example,  after  treatment  of  this  condition  with 
the  Angle  .30  inch  sectional  arch  with  upright  pins,  locked  in  tubes 
on  incisor  and  cuspid  bands  it  is  difficult  to  construct  a  retaining  appli- 
ance that  is  more  effective  than  the  operative  appliance,  hence  it  may 
be  left  in  position  for  retention. 

After  the  use  of  the  plain  expansion  arch  for  the  correction  of  simple 
cases  of  infra-occlusion  of  the  incisors,  as  in  Fig.  609,  the  expansion 
arch  may  be  left  in  position  for  retention,  or  a  lingual  arch  of  .30  inch 

substituted,  Fig.  742,  the  incisor  bands  being 
provided  with  lingual  hooks  which  engage 
with  the  lingual  arch  and  prevent  the  return 
of  the  infra-occlusion. 

In  more  pronounced  cases  of  infra-occlu- 
sion of  the  incisors  and  cuspids  in  which  the 
Fig  747     (C  5  Case)         expansion  arches  have  been  adapted  as  in 
Fig.  650,  and  intermaxillary  force  used  to 
correct  the  infra-occlusion,  the  continued  wearing  of  the  expansion 
arches  with  the  use  of  very  light  intermaxillary  elastics  is  essential  for 
the  retention. 

C.  S.  Case  illustrates  and  describes  one  of  the  most  inconspicuous 
retaining  appliances,  after  correction  of  infra-occlusion  in  his  work  on 
Dental  Orthopedia.     Its  adaptation  is  shown  in  Fig.  747. 

In  the  severe  cases  of  infra-occlusion  in  which  the  angle  of  the  man- 
dible has  been  changed  by  means  of  a  specially  constructed  head  gear 
and  chin  cap,  one  form  of  which  is  shown  in  Fig.  651,  the  continuation  of 
the  wearing  of  the  head  gear  and  chin  cap  affords  the  best  means  of 
retention  of  the  case. 

Retention  of  Infra-occlusion  of  Bicuspids.  — ^The  retention  of  cases 
after  tieatment  with  the  light  expansion  arch  for  infra-occlusion  of  the 
bicuspids  as  in  Fig.  608  consists  in  the  substitution  of  a  lingual  arch 
extending  from  one  first  permanent  molar  to  the  other  and  arranged  so 
that  it  will  pass  gingivally  to  lingual  hooks  on  bicuspid  bands  and 


RETENTION.  837 

occlusally  to  hooks  on  incisor  bands  as  in  Fig.  748.  Although  it  has  been 
claimed  by  some  writers  that  there  is  no  supra-occlusion  of  the  incisors  in 
connection  with  infra-occlusion  of  the  bicuspids,  the  author  regards  this 
theory  as  incorrect  from  the  observations  of  cases  from  practice  in  which 
the  incisors  have  been  intruded  in  their  sockets  as  much  as  the  bicuspids 
have  been  extruded.  In  this  retention,  then,  there  is  a  reciprocation  of 
the  resistance  of  the  bicuspids  to  become  intruded  and  the  resistance 
of  the  incisors  to  become  extruded. 


Fig.  748. 

Retention  of  Corrected  Infra-occlusion  of  Deciduous  and  Per- 
manent Molars. — In  Class  I  (upper  protrusion)  after  the  correction  of 
the  infra-occlusion  of  the  permanent  molars  in  a  mixed  denture  by  means 
of  intermaxillary  force  exerted  between  the  upper  and  lower  molars,  held 
apart  by  the  lower  incisors  occluding  with  a  bite  plate  as  in  Fig.  557,  the 
new  occlusal  plane  established  is  retained  by  a  continuation  of  the  use 


Fig.  749. 

of  intermaxillary  force  with  elastics  exerting  a  very  gentle  pull,  the  rubber 
bite  plate  being  worn  at  the  same  time. 

Retention  of  Mesio-distal  Changes  in  Occlusion. — As  cases 
of  the  second  and  third  classes  of  malocclusion  present  the  greatest 
difficulties  in  the  way  of  treatment,  so  also  do  they  require  exceptionally 
diflBcult  retention,  for  in  addition  to  the  necessity  of  retaining  each 
dental  arch  in  its  corrected  form  and  size,  including  the  malposed 
teeth  which  have  been  restored  to  normal  positions,  it  is  almost  always 
essential  that  the  mesio-distal  change  in  occlusion  shall  be  persistently 


838 


ORTHODONTIA. 


retained  for  some  time  after  treatment,  varying  with  the  age  of  the 
patient  and  the  extent  of  the  mesio-distal  malocclusion. 

Retention  of  Class  II. — In  Class  II,  Div.  i,  the  average  case  re- 
quires retention  of  expanded  arches,  of  corrected  malpositions  of  the  in- 
dividual teeth,  and  of  corrected  mesio-distal  changes  in  occlusion.  Also, 
the  corrected  changes  in  the  occlusal  plane,  especially  v^here  the  abnor- 
mal overbite  is  corrected,  require  especial  means  of  retention  in  addition. 

Occasionally  a  case  presents  in  which  the  restoration  of  function 
of  the  occlusal  inclined  planes  needs  no  other  retention  than  the 
normal  action  and  reaction  of  these  inclined  cusp  planes  upon  each 
other  in  occlusion  and  articulation.  A  case  of  this  kind  belong- 
ing to  the  second  division  of  Class  II  is  described  under  treatment 
of  this  class  and  illustrated  in  Figs.  68 1  and  682. 


Fig.  750. 


As  illustrative  of  the  fact  that  mesio-distal  retention  upon  the  molars 
is  not  always  necessary  after  treatment  in  the  divisions  of  Class  II, 
in  early  treated  cases,  Reoch  reports  a  case  in  which  the  retention  con- 
sisted simply  of  an  inclined  plane  of  gold  attathed  to  the  upper  central 
incisors,  illustrated  in  Fig.  664,  tending  by  its  action  at  each  closure  of 
the  mouth  to  cause  normal  locking  of  occlusal  planes. 

Antagonizing  Spurs. — The  simplest  retention  of  the  normal 
mesio-distal  relations  of  the  dental  arches, after  shifting  the  occlusion, is 
by  means  of  spurs  soldered  to  the  buccal  surfaces  of  upper  and  lower 
molar  anchor  bands,  these  spurs  being  so  related  that  they  act  as  inclined 
planes  continually  forcing  the  occluding  molars  into  their  proper  cusp 
relationship  during  each  closure  of  the  jaws. 

Fig.  749  illustrates  the  positions  of  the  buccal  spurs  for  the  retention 


RETENTION.  839 

of  the  mesio-distal  relations  established  after  treatment  of  a  case  of 
Class  II. 

The  buccal  spurs  upon  the  molar  bands  are  preferably  constructed  of 
square  wire,  of  platinized  gold  or  iridio-platinum,  afifording  flat  surfaces 
for  the  antagonizing  of  the  two  spurs  in  occlusion.  These  spurs  are 
adjusted  after  a  method  suggested  by  Watson,  being  a  modification  of 
the  spur  and  plane  method  described  by  Angle. 

Occasionally  it  will  be  found  that  the  buccal  spur  on  the  upper 
molar  band  in  Class  II  may  be  dispensed  with,  allowing  the  lower 
buccal  spur  to  antagonize  the  plane  of  the  mesial  angle  of  the  mesio- 
buccal  cusp  of  the  upper  first  molar,  especially  in  cases  in  which  the 
permanent  bicuspids  are  unerupted. 

The  buccal  spurs  are  also  effectual  in  retaining  single  molar  or 
bicuspid  teeth  which  have  been  moved  buccally  or  lingually  into 
proper  occlusion,  as  described  by  Angle. 


Fig.  751. 

Figs.  750  and  751  illustrate  the  right  and  left  occlusion  of  a  case  of 
Class  II,  Div.  I,  before  and  after  treatment.  It  is  useless  in  cases 
in  which  the  upper  incisors  are  protruded  to  the  extent  shown  in  this 
case  to  expect  that  restoration  of  function  of  the  inclined  planes  of 
the  incisors  will  be  sufficient  to  retain  the  normal  relations  of  occlusion 
which  have  been  established  in  the  incisor  region,  and  it  is  advisable 
to  retain  the  mesio-distal  change  in  occlusion  until  the  eruption  of  the 
permanent  bicuspids  in  a  case  undertaken  as  early  as  this  one. 

A  buccal  and  occlusal  view  of  the  retaining  appliances  used  in  this 
case  is  shown  in  Figs.  752  and  753,  the  antagonizing  spurs  upon  upper 
and  lower  molar  bands  serving  to  retain  the  normal  mesio-distal  rela- 
tionship established  between  the  arches. 


840 


ORTHODONTIA. 


The  lingual  arch,  acting  in  conjunction  with  cemented  incisor  bands, 
attached  with  lingual  hooks,  effectually  retains  the  upper  arch  in  its 
normal  form  and  the  upper  incisors  in  their  normal  positions. 


Fig.  752. 

^Intermaxillary  Retention  in  Class  II.— (Normal  Overbite.)     A 
method  involving  the  use  of  intermaxillary  retention  of  Class  II,  Div   i, 


Fig.  753. 

illustrated  and  described  by  Watson  in  1908,  is  still  in  use  with  but  few 
modifications.    The  upper  appliance  A, Fig.  754,  engaging  with  the  lower 


RETENTION. 


841 


appliance  by  means  of  intermaxillary  elastics,  consists  of  a  threadless 
buccal  arch,  of  18  to  20  gauge  iridioplatinum  (20  per  cent,  iridium) 
sliding  into  close-fitting  buccal  tubes  on  first  molar  clamp  bands,  a  little 
collar  soldered  to  either  side  of  the  arch  just  in  front  of  the  buccal  tube, 
causing  the  pressure  to  be  equally  distributed.     The  intermaxillary 


Fig.  754.     {Watso?i) 

elastics  are  adjusted  with  the  lower  appliance  so  as  to  preserve  a  proper 
balance  only  of  the  forces  tending  to  cause  a  return  of  the  distal  occlu- 
sion, a  very  delicate  elastic  being  finally  used  for  the  purpose.  The 
retention  of  individual  teeth  is  independent  of  this  appliance. 

A  modification  of  the  appHance  on  the  upper  dental  arch,  described 


Fig.  755.     (Watson) 

by  Watson,  consists  of  an  arch  wire,  C,  Fig.  754,  so  formed  as  to  rest  on 
the  labial  surfaces  of  the  incisors,  and  passing  between  the  cuspid  and 
first  bicuspid  on  each  side,  extends  and  is  attached  to  the  mesio-Hngual 
angle  of  the  molar  clamp  band  the  screw  of  which  is  turned  distally. 
Hooks  for  intermaxillary  elastics  are  attached  at  the  angle   formed 


842 


ORTHODONTIA. 


by  the  arch  wire  bending  lingually  in  the  cuspid  region.  This  form  of 
arch  wire  serves  to  retain  arch  expansion  in  the  bicuspid  region,  as  well 
as  the  form  of  the  anterior  portion  of  the  arch. 

The  retention  of  the  lower  arch  was  also  effected  by  means  of  a 
lingual  wire  attached  to  the  molar  clamp  band  and  re-enforced  an- 
teriorly by  a  lingual  wire  attached  from  cuspid  to  cuspid,  as  illustrated 
in  Fig.  755^.  The  six  lower  anterior  teeth  are  retained  by  banding  the 
cuspids  and  uniting  these  bands  with  a  lingual  wire  resting  above  the 
lingual  ridge.  A  lingual  arch  is  then  bent  to  fit  against  the  lingual 
surfaces  of  the  bicuspids,  resting  against  the  cuspid  bands  and  fitting 
closely  under  the  ends  of  the  wire  attached  to  the  cuspid  bands  and 
crossing  the  lingual  surfaces  of  the  incisors  in  close  proximity  to  the 
gums.  The  distal  ends  of  this  lingual  arch  are  attached  to  the  mesio- 
lingual  angle  of  the  molar  clamp  bands  with  lingual  screws  pointing 
distally,  and  the  hooks  for  intermaxillary  elastics  are  soldered  to  the 


Fig.  756. 

buccal  surface  of  these  bands.     The  object  of  the  appliance  being  thus 
made  in  two  separate  pieces  is  twofold: 

1.  The  six  anterior  teeth,  especially  the  cuspids,  are  more  perfectly 
retained  with  a  lingual  wire  from  one  cuspid  band  to  the  other  than  by  a 
lingual  arch  attached  to  molar  bands  and  resting  against  these  six 
anterior  teeth. 

2.  The  teeth  thus  retained  in  sections  have  an  opportunity  to  become 
self-supporting  more  rapidly  than  when  all  the  teeth  in  one  arch  are 
bound  together,  as  it  were,  by  a  lingual  wire  attached  firmly  to  cuspid 
and  molar  bands. 

In  the  wearing  of  these  appliances  for  retention  of  cases  of  Class  II, 
Div.  I,  the  intermaxillary  elastics  may  be  worn  at  night,  and  discarded 
after  a  time,  leaving  the  buccal  and  lingual  arches  in  position  to  retain 
the  form  and  development  of  the  dental  arches  for  a  still  longer  period. 


RETENTION. 


843 


In  the  simpler  cases  of  mixed  dentures  of  Class  II,  Div.  i.  in  which 
there  has  been  no  appreciable  change  in  the  underbite,  a  mesio-distal 
retention  only  being  necessary  in  addition  to  the  retention  of  expanded 
upper  and  lower  arches  and  corrected  individual  tooth  malpositions,  the 
author  uses  a  modification  of  this  method  in  that  the  upper  expansion 
arch  which  was  used  for  treatment  is  worn  day  and  night  during  the 
first  part  of  the  retaining  period,  with  intermaxillary  elastics  of  de- 
creasing strength,  then  in  the  second  part  of  the  retaining  period  the 
upper  expansion  arch  is  worn  with  the  most  delicate  elastics  at  night  only, 
then  alternate  nights,  and  finally  discarded.  The  expansion  arches  in 
these  cases  must  closely  fit  the  buccal  tubes  and  be  provided  with 
friction  nuts. 

The  lower  dental  arch,  when  of  regular  form,  needs  but  little  reten- 


FiG.  757. 

tion  for  lateral  development  beyond  that  afforded  by  a  single  lingual 
arch  attached  to  molar  bands,  having  intermaxillary  hooks  soldered  to 
their  buccal  surfaces. 

Occasionally,  in  more  mature  cases,  the  conditions  of  malocclusion 
will  seem  to  demand  the  continued  use  of  an  upper  lingual  retaining  arch, 
attached  to  cuspid  and  molar  bands,  and  sometimes  to  incisor  bands. 
In  these  cases,  the  buccal  arch  may  be  dispensed  with  and  the  inter- 
maxillary hooks  soldered  to  the  cuspid  bands. 

In  Fig.  756  is  exhibited  another  method  of  application  of  intermax- 
illary force  for  the  retention  of  the  normal  mesio-distal  relations  of  a 
case  of  Class  II,  Division  i  after  treatment  which  is  occasionally  used. 
An  elastic  is  stretched  from  labial  hooks  upon  upper  cuspid  bands  to 
buccal  hooks  upon  bands  on  the  lower  first  molars. 

The  retention  of  the  expanded  arches,  as  shown  in  Fig.  757,  is 
provided  for  at  the  same  time  by  the  lingual  wires  attached  to  cuspid 
and  molar  bands.     In  the  upper  arch,  D,  the  central  incisors  are 


844  ORTHODONTIA. 

also  attached  to  the  h"ngual  wire,  the  incisor  bands  having  labial  spurs 
extending  over  the  lateral  incisors,  thus  effectually  preventing  a  return 
of  the  pointed  arch  w^hich  v^as  restored  to  normal  shape  during  the 
treatment. 

The  use  of  so  many  soldered  bands  is  always  an  objectionable  fea- 
ture of  retention,  because  they  give  so  little  opportunity  for  the  teeth  to 
become  self-supporting,  and  also  because  of  the  difficulties  attending  the 
re-cementation  of  the  bands  when  one  or  more  become  loosened.  When 
necessary  to  attach  the  lingual  arch  to  incisor  and  cuspid  bands,  it  is 
advisable  to  use  lingual  hooks  bent  over  the  arch  as  suggested  by 
Lourie. 


Fig.  758.     (Rogers.) 

Retention  of  Class  II,  Div.  1,  Subdivision.— The  intermaxillary 
retention  of  the  subdivision  of  Class  II,  Div.  i,  in  which  the  occlusion 
is  normal  on  one  lateral  half  and  distal  on  the  other,  varies  but  little  from 
the  retention  of  the  corrected  bilateral  distal  occlusion,  since  it  is  neces- 
sary to  wear  a  very  light  intermaxillary  elastic  on  the  normally  related 
side  in  order  to  more  perfectly  balance  the  force  of  the  elastic  necessary 
on  the  side  formerly  in  distal  occlusion. 

Intermaxillary  Retention  in  Class  II  after  Change  of  Occlusal 
Plane. — (Abnormal  Overbite.)  In  some  of  the  cases  of  mixed  dentures 
"of  Class  II,  Div.  i,  in  which  the  occlusal  plane  has  been  changed,  the 
operative  appliances  shown  in  Fig.  557  are  used  for  retention,  the  expan- 
sion arch  being  continued  on  the  upper  in  connection  with  the  use  of  the 


RETENTION.  845 

bite  plate,  the  lower  arch  being  retained  with  a  lingual  arch  wire.  In 
these  cases  it  is  necessary  to  retain  both  a  mesio-distal  change  in  the 
dental  arches  as  well  as  a  change  in  the  occlusal  plane.  Hence,  the 
intermaxillary  elastics  should  be  adapted  as  in  the  treatment  to  exert  a 
vertical  as  well  as  a  horizontal  pull  affected  by  the  triangular  arrange- 
ment in  Fig.  557.  The  elastics  used  should  be  decreased  in  strength 
during  retention  so  that  only  the  most  delicate  intermaxillary  force  is 
needed  to  balance  the  antagonizing  resistance.  This  retention  should 
be  worn  day  and  night  during  part  of  the  period  of  retention,  and  nights 
only  for  another  period,  and  finally  discarded  after  the  eruption  of  the 
bicuspids  to  occlusion  if  the  length  of  time  of  retention  and  the  develop- 
mental changes  will  warrant  it. 

In  some  cases  it  is  advisable  to  use  the  fixed  inclined  plane  for  reten- 
tion of  these  cases  one  form  of  which  is  shown  in  Fig.  752,  a  combination 
suggested  by  Rogers  in  which  the  triangular  arrangement  of  the  inter- 
maxillary elastics  is  used  with  the  inclined  plane  for  both  treatment  and 


Fig.  759. 

retention.  A  lower  lingual  arch  is  substituted  for  the  expansion  arch 
during  retention. 

Fig.  759  illustrates  an  inclined  plane  of  looped  wire  in  connection 
with  an  apparatus  similar  to  that  shown  in  D,  Fig.  757.  The  use  of 
the  wire  loops,  suggested  by  J.  L.  Young,  makes  a  much  lighter 
inclined  plane  that  can  be  constructed  any  other  way  and  the  open 
spaces  make  it  more  easily  cleaned.  The  distal  tendency  of  the  lower 
arch  is  counteracted  by  the  inclined  plane  all  of  the  time  whether  the 
intermaxillary  elastics  are  worn  or  not,  and  in  some  cases  this  com- 
bination is  advisable. 

Retention  of  Corrected  Infra-occlusion  of  Bicuspids  and  Mo- 
lars in  Class  II,  Div.  1 . — ^The  occlusal  planes  of  both  upper  and  lower 
dental  arches  in  some  of  the  more  mature  cases  require  such  extreme 


846 


ORTHODONTIA. 


changes  that  the  tendencies  to  return  to  these  abnormal  planes  requires 
retention  by  a  continuation  of  the  use  of  the  operating  buccal  expansion 
arches  as  in  Fig.  608  or  the  use  of  lingual  arches  antagonizing  these 
reactive  tendencies  in  a  similar  manner  as  shown  in  Fig.  748. 
Occasionally  it  is  necessary,  either  after  correction  of  the  infra-occlu- 
sion of  the  lower  bicuspids  and  molars  or  of  a  supra-occlusion  of 
the  lower  incisors,  to  adopt  this  same  form  of  retention  of  the  lower 
dental  arch. 

Retention  of  Class  II,  Div.  2. — ^The  retention  of  Class  II,  Div.  2, 
differs  from  that  of  the  first  division  of  Class  II  in  very  few  respects. 
The  upper  dental  arch,  however,  presenting  with  a  torsal  or  lingual  tend- 
ency of  the  upper  incisors,  requires  usually  the  use  of  the  lingual 
retaining  arch,  with  bands  and  spurs  on  the  individual  incisors  to  resist 
the  tendency  to  rotate  or  return  to  positions  of  lingual  inclination. 


Fig.  760. 

These  cases  usually  possess  a  deep  underbite,  indicating  infra-occlusion 
of  the  bicuspids  and  molars,  and  occasionally  supra-occlusion  of  the 
incisors,  and  the  retention  of  corrected  occlusal  planes  in  this  division 
is  the  same  as  in  that  of  the  first  division  of  Class  II.  The  use  of  the 
spur  and  plane  is  well  adapted  for  retention  of  the  mesiodistal  change  in 
this  division  of  Class  11.  Occasionally,  however,  the  continued  use  of 
intermaxillary  force  may  be  indicated. 

Retention  of  Class  III. — ^The  retention  of  a  corrected  mesio- 
distal change  in  Class  III  is  usually  much  simpler  than  in  Class  II.  In  • 
early  treated  cases,  where  a  sufficient  overbite  is  obtained  after  treat- 
ment, considerable  dependence  may  be  placed  upon  the  occlusal  reten- 
tion of  the  incisors  in  normal  occlusion.  In  early  treated  cases  in  which 
it  is  impossible  to  obtain  much  of  an  overbite  of  the  incisors,  an  upper 


CONSTRUCTIVE   TECHNIC. 


847 


lingual  arch  holding  the  upper  incisors  forward,  attached  to  molar 
bands,  with  buccal  spur  and  a  lower  buccal  plane  reversed  from  the 
relations,  shown  in  Fig.  749  for  Class  II  retention  is  advisable. 

In  more  mature  cases  of  greater  severity,  as  in  Fig.  760,  intermaxillary 
retention  adjusted  as  in  Fig.  761  from  a  lower  expansion  arch  to  hooks 
to  upper  molar  bands  attached  to  a  lingual  arch  seems  necessary. 

The  chief  consideration  beyond  that  of  the  correction  of  mouth- 
breathing  habits  is  the  establishment  of  an  overbite.  In  some  cases  it  is 
necessary  to  discontinue  treatment  if  an  "open  bite"  condition  is  liable 


Fig.  761. 

to  ensue  on  continued  treatment  with  intermaxillary  force,  hence,  in  the 
use  of  this  force  for  retention  the  occlusal  relations  of  the  upper  and 
lower  incisors  must  be  carefully  guarded. 


PART  XIV. 


CONSTRUCTIVE  TECHNIC. 


Necessity  for  Technical  Instruction. — ^The  necessity  for  tech- 
nical instruction  in  constructing  appliances  or  parts  of  appliances  adapted 
for  the  individual  case  is  more  evident  at  the  present  writing  than  at  the 
time  of  publication  of  the  first  edition  of  this  chapter  in  which  the  author 
stated  that  "the  orthodontist  of  the  future  must  be  a  constructive  ortho- 
dontist." The  ready  made  appliance  needs  as  much  reconstruction 
work  upon  it  to  adapt  it  to  the  dental  arch,  as  if  it  were  made  entirely 
in  the  laboratory.  The  use  of  the  plain  bands  on  molars  in  preference 
to  the  clamp  band  for  the  majority  of  cases,  the  multiplicity  of  bands  and 
tubes  upon  the  anterior  teeth,  the  soldering  of  telescoping  pins  and  the 


848  ORTHODONTIA. 

adjustment  of  expansion  arches  in  the  technic  of  the  newer  appliances 
for  bodily  movement,  requires  constructive  ability  of  no  mean  order. 

Again,  the  field  of  retention,  with  its  unlimited  possibilities  in  the  me- 
chanical construction  of  retaining  appliances,  requiring  a  combination  of 
art  and  esthetics  in  the  production  of  an  efi&cient  and  inconspicuous 
apparatus,  looms  up  before  one  with  a  demand  for  the  most  consum- 
mate skill  in  the  art  of  construction. 

To  the  lover  of  the  art  of  orthodontia,  also,  the  various  phases  of 
constructive  technic,  in  both  the  mechanical  and  esthetic  features, 
present  considerable  scope  for  skill  and  originality. 

Materials  for  Construction  of  Appliances. — The  first  considera- 
tion in  a  material  for  the  construction  of  appliances  to  be  used  in  the 
mouth  should  be  the  selection  of  a  metal  or  alloy  that  will  be  the  least 
affected  by  the  fluids  of  the  mouth,  and  which  in  turn  will  least  affect 
the  surfaces  of  the  teeth  with  which  it  comes  into  contact. 

Any  orthodontic  appliance  in  the  mouth  interferes  more  or  less  with 
the  natural  cleansing  action  upon  tooth  surfaces  of  the  saliva,  and  of  the 
tongue  and  cheeks  in  mastication,  and  to  minimize  this  tendency,  an 
appliance  should  not  only  be  simple  in  design  and  application,  but 
should  be  constructed  of  materials  which  will  give  the  greatest  im- 
munity from  caries. 

Providing  the  quality  of  efficiency  is  not  impaired  by  such  a  selec- 
tion of  material,  the  choice  of  a  metal  or  alloy  for  appliance  construction 
is  of  paramount  importance,  the  manner  of  its  application  and  subse- 
quent adjustment  being  of  lesser  moment. 

So  many  different  metals  have  been  advocated  in  the  past  for  the 
construction  of  appliances  that  it  is  necessary  to  point  out  from  the 
standpoint  of  clinical  experience  those  metals  or  alloys  which  are  of  the 
greatest  advantage  for  use  in  the  mouth,  where  physiological  conditions 
must  be  taken  into  account. 

German  silver  was  used  to  the  exclusion  of  almost  every  other  metal 
or  alloy  for  many  years  in  the  United  States,  and  for  mechanical  effi- 
ciency, except  in  the  possession  of  the  requisite  tempers  for  the  manufac- 
ture of  expansion  arches  and  bands,  was  almost  an  ideal  material  for  the 
purpose. 

German  silver,  however,  is  acted  upon  by  sulphuric,  hydrochloric, 
and  nitric  acids;  even  a  weak  acid  like  acetic  acid  will  attack  it,  form- 
ing a  combination  of  the  basic  acetates  of  copper,  which  at  least  is  not 
desirable.     Pyrozone  and  iodine  attack  it  vigorously. 

In  the  mouth  German  silver  discolors  and  in  a  large  number  of 
cases  corrodes  upon  the  surface,  sometimes  to  the  extent  of  perforation 


CONSTRUCTWE    TECHNIC.  849 

of  a  molar  anchor  band.  The  pits  formed  by  this  corrosion  become 
breeding  places  for  bacteria,  retaining  a  certain  amount  of  the  soft 
foods  in  their  cup-like  pockets.     (Grieves.) 

Potassium  sulfo-cyanate,  which  is  normally  present  in  the  saliva,  and 
which  gives  immunity  to  caries  when  present  in  sufficient  quantity, 
badly  discolors  German  silver. 

German  silver  will  sometimes  leave  upon  tooth  surfaces,  a  metallic 
stain  which  is  difficult  to  remove,  unless  careful  prophylactic  measures 
are  taken  during  the  treatment  of  a  case. 

From  a  physiological  standpoint,  then,  there  is  much  to  be  desired 
in  a  combination  of  metals  for  appliances  to  be  used  in  the  mouth  other 
than  is  possessed  by  the  alloy  of  German  silver. 

A  material  which  will  not  discolor  nor  corrode,  and  which  is  not 
attacked  by  the  fluids  of  the  mouth,  at  the  same  time  possessing 
the  requisite  temper  for  all  the  parts  of  an  appliance,  is  much  to  be. 
preferred. 

The  alloys  of  gold  and  platinum  possess  all  these  requisite  qualifi- 
cations, and  are  made  up  in  the  form  of  band  material  and  wire, possess- 
ing high  degrees  of  temper  and  high  fusing  points. 

The  alloys  of  gold  and  platinum  will  neither  corrode,  discolor,  nor 
be  affected  by  any  acid  or  alkali,  except  aqua  regia.  The  fusing  point 
of  platinum  is  1775°  Cent.,  of  gold,  1075°  Cent.  An  alloy  composed  of 
90  per  cent  gold  and  10  per  cent  platinum  fuses  at  a  temperature  of 
1130°  Cent.,  which  is  very  significant,  proving  that  pure  gold  may  be 
used  as  a  solder  upon  this  alloy  without  danger  of  fusing  the  latter,  since 
the  fusing  point  of  the  alloy  is  55  degrees  higher  than  the  fusing  point 
of  gold. 

The  points  of  chief  importance  in  a  gold  alloy  for  appliance  con- 
struction are  that  it  shall  contain  sufficient  platinum  so  that  the  fusing 
point  will  be  so  high  that  the  ordinary  blowpipe  flame  will  not  melt  it 
while  soldering  and  that  it  shall  have  the  requisite  temper. 

Gold  alloys  without  platinum  can  be  used,  but  invariably  when  sol- 
dered attachments  are  made  to  the  arch  in  these  alloys,  if  anything 
higher  than  i8k  solder  is  used,  the  gold  alloy  is  in  danger  of  being 
melted. 

With  platinum  alloyed  with  the  gold  in  proper  proportion,  soldered 
attachments  may  be  made  to  an  arch  of  the  alloy  with  22k  solder  and 
even  pure  gold. 

Soldiering  Requirements. — ^The  attainment  of  skiU  in  constructive 
technic  in  orthodontia  lies  chiefly  in  one's  ability  to  perform  difficult 
soldering  operations  in  a  rapid  and  efficient  manner,  involving  a  train- 
S4 


850 


ORTHODONTIA. 


ing  of  the  eye  as  well  as  the  hand  in  the  building  up  of  the  units  of  a 
given  appliance. 

The  technic  of  the  orthodontist  is  not  up  to  date  without  every 
facility  for  easier  and  more  rapid  methods  of  soldering  than  are  obtain- 
able by  the  investment  of  pieces  to  be  united,  or  the  approximation  of 
parts  by  the  use  of  bulky  tweezers,  and  the  use  of  the  large  flame  of  the 
Bunsen  burner. 

The  requirements  for  this  class  of  soldering  operations  are  as  follows 

1.  A  blowpipe  flame  of  proper  fineness  and  easily  controllable. 

2.  Clean,  bright  surfaces  on  parts  to  be  united, 

3.  Easy  flowing  solders,  in  convenient  form  for  use. 

4.  A  quickly  acting  flux  in  convenient  form  to  apply. 

5.  Perfect  approximation  and  fixation  of  parts  to  be  united. 

The  Blowpipe. — ^Taking  up  these  re- 
quirements in  order,  the  form  of  blowpipe 
should  receive  the  first  consideration.  The 
necessities  of  the  work  require  that  a  blow- 
pipe should  not  be  more  than  a  few  inches 
in  height,  the  burner  to  be  upon  a  substan- 
tial base,  and  having  attached  to  it  easily 
adjustable  valves  for  both  gas  and  air,  the 
tip  of  the  burner  being  so  constructed  that 
a  continuous  fine,  needle  point  flame  of  suffi- 
cient intensity  may  be  obtained,  and  varied 

in  size  and  intensity  by  valve  control  to  suit  the  needs  of  the  varying 
size  and  bulk  of  appliances  to  be  soldered. 

A  blowpipe  which  most  perfectly  answers  these  requirements,  Fig. 
762,  is  the  invention  of  J.  L.  Young.  The  burner  pillar  is  in  sections, 
having  a  ball  and  socket  at  its  lower  end  to  enable  it  to  be  revolved  in  the 
base  in  any  direction  desired,  and  from  a  vertical  to  a  horizontal  posi- 
ion,  a  great  advantage  in  soldering  appliances.  By  turning  a  ring,  and 
closing  an  air  valve  a  Bunsen  flame  is  secured. 

A  compressed  air  outfit  is  most  desirable  in  connection  with  a  blow- 
pipe of  this  kind,  as  the  ordinary  bellows  will  not  answer  the  purpose, 
the  use  of  the  foot  in  pumping  moving  the  whole  body  enough  to  seri- 
ously disturb  the  soldering  operations. 

Removal  of  Oxidation. — ^A  clean,  bright  surface  is  always  essen- 
tial to  a  successful  attachment  of  solder,  and  oxidized  surfaces  should 
be  carefully  polished  with  a  fine  sandpaper  disk  in  the  engine  be- 
fore soldering,  or  boiled  in  acid  or  alum  solution  and  polished  on  the 
lathe. 


Fig.  762. 


CONSTRUCTIVE   TECHNIC. 


851 


Solder. — While  the  higher  carat  gold  solders  in  sheet  form  may  be 
cut  up  to  any  requisite  degree  of  fineness  for  marking  the  various  sol- 
dered attachments  (except  for  iridio-platinum  and  the  attachments  of 
pins  and  tubes  for  the  sectional  arch),  the  use  of  solder  in  the  form  of  fine 
wires  is  far  superior. 

These  wire  solders  should  be  cut  up  in  convenient  lengths  with  a 
ring  at  one  end  as  in  Fig.  763  to  distinguish  them  readily  from  platinum 
and  gold  alloyed  wire. 


Fig.  763. 

With  this  form  of  solder,  there  is  a  great  saving  of  time,  as  the  end  of 
the  wire  solder  has  only  to  be  touched  to  the  surface  of  one  of  the  parts 
of  an  appliance  to  be  attached,  when  a  sufficient  quantity  will  be  fused 
in  the  required  position.  In  the  use  of  the  other  sheet  form  of  solder, 
besides  the  number  of  motions  required  to  pick  up  and  place  a  small 
piece  of  it  in  position,  it  is  continually  slipping  off  from  the  appliance 
and  lost,  an  annoyance  not  encountered  with  the  wire  solder. 


Fig.  764. 

Easy  flowing  gold  solders  in  wire  form  are  now  obtainable  at  the 
depots,  and  in  the  use  of  the  gold  solders,  for  making  attachments  upon 
gold  and  platinum  appliances,  an  intelligent  use  of  the  higher  carats 
(22k)  in  the  uniting  of  primary  parts,  with  the  consecutive  use  of  a  lower 
carat  (i8k)  for  secondary  attachments,  will  give  assurance  of  the  success 
of  each  soldering  operation  in  their  order,  and  if  the  degree  of  heat  is 


Fig.  765. 

properly  gauged,  the  union  of  a  number  of  very  small  parts  in  close 
approximation  may  be  much  more  safely  accomplished  than  if  but  one 
grade  of  solder  were  used.  It  is  possible,  however,  to  become  so  adept 
that  most  of  the  soldering  of  gold  and  platinum  appliances  may  be  done 
with  one  grade  of  solder.  In  soldering  iridio-platinum,  pure  gold  must 
be  used  as  a  solder  and  it  can  also  be  used  in  wire  form  to  advantage. 


852 


ORTHODONTIA. 


Fluxes. — Next  in  importance  in  soldering  operations  is  the  use  of  a 
flux  which  will  quickly  cleanse  the  oxidized  surfaces  so  that  the  solder 


willxflow  readily.  Borax  is  the  usual  constituent  of  all  fluxes  for  hard 
solders  of  either  gold  or  silver,  and  when  properly  calcined  and  prepared 
for  conv'enient  use,  will  answer  every  purpose.     A  favorite  method  of 


Fig.  767 

some  operators  is  to  have  a  specially  prepared  borax  slate  with  various 
sizes  of  solder  mixed  with  creamed  borax  on  its  surface,  ready  for  imme 


CONSTRUCTIVE    TECHNIC. 


853 


diate  use.  Considerable  time  is  consumed  in  mixing  the  borax  before 
every  soldering  operation  in  this  manner,  and  the  displacement  of  the 
solder  from  position  when  placed  in  the  flame  is  an  annoying  and  not 
infrequent  occurrence. 

To  overcome  these  difficulties,  the  author  has  combined  a  flux  in 
a  specially  prepared  wax  soldering  stick,  of  the  sizie  and  shape  shown  in 
Fig.  764,  and  containing  a  calcined  borax  flux,  which  is  not  only  instan- 
taneous in  application,  but  by  means  of  the  wax  body  fixes  cut  pieces  of 


Fig.  768. 

solder  in  position  so  that  they  cannot  be  displaced  before  fusion  takes 
place.  The  only  caution  necessary  in  its  use  is  that  the  surface  to  be 
soldered  should  be  slightly  warmed,  and  not  heated  to  redness,  before 
touching  with  the  wax  stick.  -'i-o  p!-. 

Borax  fluxes  incorporated  in  a  vaseline  base  are  also  to  be  obtained 
in  the  depots  and  give  very  satisfactory  results. 

A  pair  of  solder  t^veezers  of  the  size  and  shape  shown  in  Fig.  765, 
should  be  used  for  picking  up  pieces  of  solder,  and  its  points  should  be 
kept  clean  and  out  of  the  soldering  flame  in  order  to  be  in  proper  con- 
dition to  use. 


For  cutting  gold  and  platinum,  iridio-platinum,  and  sheet  solder,  a 
pair  of  small  shears  with  especially  strong  blades,  such  as  is  illustrated 
in  Fig.  766,  is  especially  adapted  for  use  at  the  operating  cabinet,  being 
preferable  to  the  larger  laboratory  shears  for  the  purpose. 

Approximation  of  Parts  to  be  Soldered. — ^A  number  of  years  ago, 
the  author  devised  a  set  of  delicate  clamps,  Fig.  767,  for  the  approxima- 
tion of  the  various  parts  of  bands  and  appliances  while  being  united 
with  solder,  and  the  fifteen  years  of  constant  use  and  improvement  have 


854 


ORTHODONTIA. 


brought  them  up  to  a  standard  of  perfection  which  makes  the  operation 
of  soldering  extremely  simple,  accurate  and  rapid,  as  well  as  saving  in 
time,  patience,  and  nerves  from  the  hand  soldering  method.  There  is 
hardly  a  single  practical  combination  of  appliance  parts  that  cannot  be 
perfectly  adjusted  in  these  clamps. 

Hand  Soldering. — ^The  hand  soldering  technic,  in  which  parts  of 
appliances  are  held  in  the  fingers  and  adjusted  by  resting  some  of  the 
fingers  of  one  hand  against  those  of  the  other,  is  a  splendid  manual 
training,  and  occasionally  may  be  advantageously  used  in  combination 
with  mechanical  methods  of  holding  parts  of  appliances. 

Construction  of  Plain  Bands  for  Incisors  and  Cuspids. — One  of 
the  most  important  adjuncts  to  the  direct  application  of  force  to  the 
upper  and  lower  ten  anterior  teeth,  is  the  plain  band,  or  Magill  band  as 
it  is  often  called  after  its  originator. 

For  use  with  the  expansion  arch,  plain  bands  may  be  made  of  gold 
and  platinum  of  .003  inch,  thickness,  and  of  an  average  width  of  .09 


Fig.  770. 


inch.  With  the  Angle  sectional  arch,  the  bands  should  be  made  of 
iridioplatinum  .003  inch  in  thickness  and  of  an  average  width  of  .19 
inch,  as  this  material  can  be  used  much  thinner  than  the  gold  and 
platinum  material,  and  will  occupy  correspondingly  less  space  between 
incisors  where  all  of  them  are  banded. 

Gold  and  platinum  band  material  is  now  furnished  by  the  depots  in 
strips  of  the  form  shown  in  Fig.  768  in  any  length  desired. 

The  band  material  should  first  be  formed  into  a  loop,  the  edges 
of  which  are  forced  between  the  mesial  and  distal  approximating  sur- 
faces of  the  tooth  to  be  banded  and  the  adjoining  teeth,  the  free  ends 
directed  lingually  or  labially  as  desired,  and  after  pulling  the  band 
material  taut  on  the  tooth,  it  should  be  removed  and  the  proximal 
edges  festooned  so  that  they  pass  just  beneath  the  labial  and  proximal 
gum  margins.  The  ends  of  the  loop  should  then  be  pinched  together 
close  to  the  tooth  surface,  as  at  A  in  Fig.  769.  The  ends  of  the  band 
material  should  meet  at  right  angles  at  the  point  of  union,  so  as  to  form 


CONSTRUCTIVE   TECHNIC. 


855 


a  continuous  inner  surface  of  the  band  when  soldered,  asatB  in  the 
same  cut. 

The  author's  band-forming  ph'ers,  shown  in  Fig.  770,  are  especially 
designed  for  this  purpose,  having  concavo-convex  beaks  which  accu- 
rately fit  the  surface  of  the  teeth.  Fig.  771  illustrates  the  nicety  with 
which  the  concave  edge  of  the  beaks  fits  the  labial  surface  of  an  upper 
incisor,  when  the  pinch  is  made  on  the  labial  surface,  and  the  accuracy 
with  which  the  convex  edge  fits  the  lingual  surface  of  a  lower  incisor. 

The  plain  band  should  be  fitted  closely  to  the  tooth  surface,  for  there 
will  always  be  sufficient  space  for  the 
cement  for  proper  fixation  of  the  band 
and  protection  of  the  tooth  surface. 
The  burnishing  of  the  margins  of  the 
band  may  be  done  after  it  is  in  position 
and  the  cement  still  soft.  Oftentimes, 
in  forming  the  cuspid  band,  it  is  neces- 
sary to  make  an  additional  pinch  at  the 
mesial  and  distal  angles,  filling  the 
pinched  portion  with  solder  and  trim- 
ming off  the  projecting  edge. 

Soldering  the  Band. — In  uniting 
the  ends  of  the  plain  band  with  solder, 
they  should  be  held  in  a  suitable 
tweezer,  or  in  an  automatic  clamp  as 
in  Fig.  772,  and  having  been  fluxed, 
the  band  is  held  in  the  fine  flame  of 
the  blowpipe,  a  piece  of  wire  solder 
touching  the  edges  of  the  joint  until  it 
is  fused.  The  surplus  ends  are  next 
cut  off,  and  the  ridge  which  remains  polished  smooth  with  the  sand- 
paper disc,  after  which  the  band,  if  of  gold  and  platinum,  is  trans- 
ferred to  a  boiling  solution  of  acid  or  alum  to  deoxidize  it,  and  then 
polished.  If  it  is  not  to  be  cemented  on  at  once,  it  should  be  properly 
indexed  and  filed  until  the  next  sitting. 

The  iridio-platinum  band  material  for  use  with  the  sectional  arch 
should  be  roughened  by  drawing  it  over  a  round  file  No.  3  cut,  leaving  a 
surface  to  which  the  cement  will  better  adhere.  Also,  in  making  the 
plain  band  of  this  material  for  use  with  the  sectional  arch,  one  edge  of 
the  iridio-platinum  band  should  be  trimmed  to  pass  beneath  the  free 
margins  of  the  gum,  the  edge  presenting  occlusally  to  be  festooned  so 
that  it  will  be  gingival  to  the  contact  points  when  in  position  which  is  of 


Fig.  771. 


856 


ORTHODONTIA 


especial  importance  when  all  of  the  incisor  teeth  are  banded,  economiz- 
ing the  space  of  a  double  thickness  of  band  material  at  the  contact 
points. 

Accessories  to  the  Plain  Band.— As  the  plain  band  is  usually 
utilized  for  the  more  direct  attachment  of  ligatures,  and  for  retaining 
appliances,  as  well  as  for  lever  tubes  and  traction  screw  tubes,  the 
various  methods  of  making  these  attachments  should  be  carefully 
studied.  Where  the  banded  tooth  does  not  need  rotation,  but  simply 
a  direct  movement  toward  the  arch,  a  notch  in  the  seam  of  the  band 
will  prevent  the  ligature  from  slipping,  as  at  A,  Fig.  773. 


Fig.  772. 

Lingual  spurs  for  rotation  may  be  attached  as  at  B,  Fig.  773. 
The  band  should  be  held  in  a  tweezer  or  a  No.  i  clamp  in  the 
left  hand,  and  a  length  of  wire  solder  adjusted  with  the  right  hand  to  the 
point  at  which  it  is  desired  to  attach  the  spur,  and  the  parts  to  be  united 
are  held  in  the  flame  until  the  end  of  the  wire  solder  fuses,  when  the 
band  is  quickly  removed,  the  surplus  solder  cut  off,  and  the  spur  finished. 

The  retaining  spur  shown  at  D,  Fig.  773,  is  attached  as  follows: 
a  length  of  the  retaining  wire  is  held  against  the  band  with  the  right 
hand,  the  surface  of  the  band  having  had  a  small  piece  of  solder  fused 


A  B  c  D  E  F 

Fig.  773. 

upon  it  previously.  The  band  itself  is  held  in  a  tweezer  or  the  No.  i 
clamp. 

The  lever  tube,  at  C,  Fig.  773,  preferably  square,  is  cut  off  the  de- 
sired length  and  held  in  approximation  with  the  surface  of  the  band  by 
the  No.  3  clamp  alone. 

Larger  sized  tubing  for  the  ends  of  the  traction  screw,  as  at  E  and  F, 
Fig.  773,  may  be  adjusted  to  position  with  the  Nos.  2  and  4  clamps^ 
as  illustrated  in  Fig.  767.  The  short  tubes  may  be  held  in  the  tip  of 
the  No.  4  clamp  at  any  desired  angle  to  the  band  while  being  soldered, 
being  especially  useful  in  the  attachment  of  the  tube  at  one  corner  of  a 
cuspid  band  for  the  end  of  the  traction  screw. 


CONSTRUCTIVE    TECHNIC.  857 

Hooks  and  Spurs  for  the  Expansion  Arch. — For  convenience  in 
use,  and  saving  of  time  at  the  chair,  a  number  of  pieces  of  iridio- 
platinum,  and  gold  and  platinum  wire  of  two  different  sizes,  i8  and  21 
gauge,  B.  &  S., about  four  or  five  inches  long,  should  be  kept  in  stock. 

Hooks  may  be  easily  made  by  bending  a  step  in  the  end  of  one  of 
these  wires  as  shown  in  Fig.  774,  the  end  soldered  to  the  expansion 
arch  in  the  desired  position,  and  the  surplus  wire  cut  off. 

Spurs  for  the  expansion  arch  should 
preferably  be  made  of  the  iSk  wire  solder,  <^r'  '""""S-  I 

attached  similarly  to  the  spurs  on  plain  -^ 

bands. 

Fig   774. 

Construction  of  the  Plain  Anchor 

Band. — H.  A.  Baker  has  devised  a  valuable  method  of  construction 
of  the  plain  anchor  band.  The  method  is  as  follows:  Upon  a  plaster 
cast  of  the  teeth  trim  down  the  second  bicuspid  and  second  molar  at  an 
oblique  angle  from  their  occlusal  surfaces  to  1-32"  or  1-16"  below  the 
gum  line  adjacent  to  the  first  molar  which  is  to  be  used  for  the  anchor 
tooth,  as  in  Fig.  775. 

Continue  the  labial,  lingual,  and  proximate  surfaces  of  the  molar 


Fig.  775. 

on  vertical  lines  into  the  plaster  cast  beyond  the  gingivae,  extending 
these  surfaces  to  a  level  1-32''  to  1-16"  below  the  gum  margins  and 
preserving  the  contour  of  the  tooth.  Varnish  the  exposed  portions 
of  the  tooth  with  shellac  to  obtain  a  hard  surface.  A  plain  band  is 
then  made  to  fit  the  first  molar,  soldering  the  joint  upon  the  lingual 
surface  and  afterward  burnishing  the  edges  of  the  band  into  the  grooves 
and  depressions  on  the  labio-occlusal  and  linguo-occlusal  aspects  of 
the  tooth.     The  upper  edge  of  the  band  should  extend  underneath 


858 


ORTHODONTIA. 


the  gum  a  short  distance.  The  band  should  next  be  fitted  to  the 
natural  tooth,  contouring  in  the  gingival  edge  of  the  band  enough  so  that 
the  band  will  spring  over  the  widest  diameter  of  the  crown  of  the  molar. 
The  first  molar  should  be  separated  from  the  adjacent  bicuspid  and 
second  molar  so  that  the  plain  band  will  slip  over  the  crown  of  the 
first  molar  freely,  this  separation  being  made  during  the  interval 
between  the  first  and  second  visits  of  the  patient. 

The  buccal  tubes  may  be  soldered  upon  the  plain  bands  on  the 
first  molars  and  the  expansion  arch  adjusted  and  aligned  upon  the 


Fig.  776. 

plaster  cast,  so  that  at  the  second  sitting  of  the  patient,  the  molar 
bands  may  be  cemented  in  place  and  the  expansion  arch  adjusted 
upon  the  natural  teeth.  The  method  described  has  many  advantages, 
chief  of  which  are  the  greatercomfort  for  the  patient,  and  the  expendi- 
ture of  a  minimum  amount  of  time  in  fitting  the  appliance  to  the 
natural  teeth. 

The  author's  method  of  making  plain  anchor  bands  is  somewhat 
dififerent  except  in  the  general  contouring  necessary  for  the  adapting  of 


Fig.  777 


the  band  to  the  anchor  tooth.  A  number  of  convenient  sizes  of  cylin- 
drical bands  previously  soldered  are  kept  in  stock,  Fig,  776,  ready  for 
immediate  use.  These  sizes  for  the  average  permanent  molars  are  in 
length  of  band  material  as  follows:  1.38  inches,  1.40  inches,  1.42 
inches,  1.43  inches,  1.45  inches,  1.47  inches,  1.50  inches,  1.52  inches, 
1.55  inches.  The  ends  of  these  sections  of  band  material  are  first 
beveled  oppositely  with  a  file,  the  band  material  formed  into  a  cylinder 
with  the  bevels  lapping.  The  ends  are  soldered  with  i8k  solder,  or 
with  24k  gold,  the  latter  making  the  union  soft  and  pliable. 


CONSTRUCTIVE    TECHNIC. 


859 


A  band  is  selected  which  will  fit  tightly  when  slipped  over  the  crown 
of  the  molar  past  the  contact  points.  It  is  then  removed  and  the  oc- 
clusal edge  contoured  inward  all  around,  when  it  is  replaced  on  the  molar 
and  adapted  to  the  grooves  and  cusps  with  the  instrument  illustrated 
in  Fig.  582.     The  band  is  removed  once  more  and  the  buccal  and 


Fig.  778. 

lingual  edges  which  present  gingivally  also  contoured,  so  that  it  will 
cling  tightly  to  the  tooth  on  these  edges,  when  it  is  ready  for  attach- 
ing the  buccal  tubes,  lingual  wires,  etc. 

Assembling  the  Parts  of  the  Anchor  Clamp  Band.— The  molar 
clamp  band  is  made  up  of  a  short  piece  of  band  material,  and  a  lingual 


Fig.  779. 

screw  passing  through  a  short  tube  soldered  at  one  end  of 
the  band,  adjusted  with  a  nut  turned  upon  the  lingual  screw. 
For  the  construction  of  the  clamp  band,  the  author 
P  has  invented  a  set  of  five  special  clamps  which  enable 
I  the  operator  to  quickly  assemble  and  solder  the  several 
I    parts  of  the  clamp  band. 

For  adjusting  and  soldering  the  band  and  the  lingual 
screw,  the  author  makes  use  of  No.  6  special  clamp,  which  holds  the 
two  parts  in  adaptation  during  the  soldering  operations,  as  shown 
in  Fig.  777.  The  solder  and  flux  are  always  placed  between  the 
parts  to  be  united  before  placing  in  the  flame. 

The  short  tube  is  held  in  apposition  a  short  distance  from  the  other 
end  of  the  band  with  a  No.  7  clamp  of  the  set  shown  in  Fig.  778.  In 
case  the  lapping  end  is  not  desired,  the  short  tube  is  held  on  the 
extreme  end  of  the  band  with  clamp  No.  8,  shown  in  Fig.  779. 


86o  ORTHODONTIA. 

The  band  is  then  formed  in  a  circle,  the  screw  thrust  through  the 
lingual  tube  and  the  nut  adjusted  to  it,  when  it  is  ready  for  the  attach- 
ment of  the  buccal  tube. 

Soldering  Buccal  Tube  on  the  Anchor  Clamp  Band. — ^This  oper- 
ation is  one  that  is  frequently  done  and  requires  so  much  exactness  that 
the  aid  of  special  clamps  is  almost  indispensable  to  facilitate  rapid  and 
correct  soldering  of  these  parts. 

Almost  two-thirds  of  the  molar  bands  purchased  at  the  depots  have 
to  be  subjected  to  a  change  in  the  position  of  the  tube  so  as  to  secure 
proper  alignment  of  the  arch  wire  as  in  Fig.  780. 

During  the  treatment  of  Class  II  and  III  cases,  the  tipping  of 
the  anchor  teeth  distally  and  mesially  requires  a  re-alignment  of  the  an- 
chor tubes  occasionally  to  keep  up  the  efficiency  of  the  anchorage. 


rN. 


a--' 


\ ;   y    i 


r\ 


■1/ 


HBBBSntBWnCBB 


iA 


Fig.  7S0. 

To  prevent  the  expansion  arch  from  dropping  below  the  edges  of  the 
incisors,  as  at  A,  Fig.  780,  in  a  Class  II  case,  the  anchor  clamp-bands 
should  be  removed  and  the  buccal  tubes  realigned  so  that  the  expan- 
sion arch  will  rest  upon  the  surfaces  of  the  incisors  as  at  B,  Fig.  780. 

The  technic  of  this  operation  is  as  follows: 

The  molar  clamp  band  is  held  in  a  vice-like  grip  in  the  dog  jaw 
of  special  clamp  No.  9  (Fig.  781)  which  is  attached  to  the  distal  part 
of  the  clamp  band  so  as  to  enable  this  clamp  to  be  held  in  the 
fingers  of  the  left  hand,  while  those  of  the  right  control  clamp  No.  10, 
which  engages  the  buccal  tube,  with  the  mesial  end  toward  the  handle 
of  the  clamp. 

Having  previously  attached  a  piece  of  solder  on  the  buccal  side 
of  the  surface  with  the  wax  flux,  at  the  point  at  which  the  tube  is  to  be 


CONSTRUCTIVE    TECHNIC. 


86i 


joined,  the  right  angle  arm  of  the  No.  9  clamp  is  placed  on  the  lingual 
side  of  the  band,  and  the  arm  holding  tube  is  allowed  to  drop  down 
into  position  on  the  buccal  surface  of  the  band.  The  tube 
is  aligned  horizontally  with  the  edge  of  the  band,  and  then 
the  clamp  band  and  tube  are  held  in  the  flame  of  blowpipe 
until  the  solder  is  perfectly  fused. 

Construction  of  Complicated  Retaining  Appliances. 
— It  has  been  the  custom  of  many  operators  to  make,  at 
the  chair,  retaining  appliances  soldered  to  a  lingual  wire, 
fitting  the  lingual  wire  from  one  band  to  the  next,  solder- 
ing and  fitting  to  place,  with  the  possibility  of  inaccuracy 
and  failure  of  the  appliance  to  do  the  work  for  which  it  was 
intended. 

The  author  has  given  up  this  method  of  attaching 
the  bands  to  the  lingual  wire,  preferring  in  every  case  to 
make  and  fit  the  bands  to  the  teeth  and  solder  the  lingual 
wire  to  the  bands  upon  a  plaster  cast,  obtained  from  a 
plaster  or  modelling  compound  impression  of  the  teeth 
with  the  bands  in  position.  The  bands  are  replaced 
in  the  impression  and  the  cast  poured,  the  bands  ap- 
pearing upon  the  teeth  of  the  plaster  cast  when  the  im- 
pression material  has  been  removed. 

Laboratory  Soldering  Stand. — ^A  reversible  blow- 
pipe. Fig.  782,  attached  to  a  soldering  stand  has  been 
made  up,  at  the  suggestion  of  the  author,  for  laboratory  use 
in  cases  where  appliances  are  soldered  upon  plaster  casts. 
By  means  of  the  swivel  joints  of  the  blowpipe,  the  flame 
may  be  directed  upon  any  portion  of  the  inside  circum- 
ference of  the  soldering  block,  and  fixed  at  any  desired 
position.  The  position  of  the  blowpipe  is  under  such  per- 
fect control  that  the  direction  of  the  flame  may  be  changed 
from  left  to  right,  up  or  down,  on  or  away  from  the  ap- 
pliance by  a  slight  pressure  on  the  handle. 

Soldering  Technic  of  the  Angle  Sectional  Arch. — 
The  constructive  technic  of  the  new  Angle  sectional  arch 
requires  more  delicacy  of  manipulation,  especially  in  solder- 
ing, than  the  assembling  of  the  parts  for  use  with  the  plain 
expansion  arch  and  its  anchor  bands  and  auxiliary  lingual 
wires,  etc.  Hand  soldering,  although  still  effective  for 
the  uniting  of  the  parts  of  the  new  appliance,  has  given  place  largely  to 
methods  whereby  the  smaller  and  more  delicate  parts  to  be  united, 


Fig.  781. 


862 


ORTHODONTIA. 


such  as  the  vertical  tubes  to  the  plain  bands  and  the  upright  locking  pins 
on  the  middle  arch  sections,  are  held  in  a  specially  constructed  jig  or  an 

automatic  clamp  of  special  design. 
One  method  (Angle)  of  solder- 
ing the  vertical  tube  to  the  plain 
band  is  to  place  a  staple  of  solder, 
Fig.  783  {i8k  for  gold  and  platinum 
and  24k  gold  for  iridio-platinum 
bands)  upon  the  mark  on  the  labial 
surface  of  the  band,  lay  the  tube 
upon  it,  and  hold  the  band  in  the 
flame  of  the  blow^pipe  v^^ith  a  solder 
tweezer  until  the  staple  fuses. 

Another  method,  suggested  by 
the  author,  is  to  use  an  automatic  clamp,  Fig.  784,  for  holding  the 
vertical  tube  in  position  in  addition  to  the  staple  solder.  The  upper 
arm  of  the  clamp  has  inserted  into  it  a  short  section  of 
stub  steel  wire,  tapered  at  one  end  to  receive  and  tightly 
hold  the  vertical  tube  so  that  it  cannot  be  lost  or  dis- 
placed during  soldering. 

A  still  more  delicate  soldering  operation  is  that  of 
uniting  the  arch  pins  to  the  middle  section  at  the  indi- 
cated points  and  at  the  proper  angles  of  inclination  for  each  tooth.     The 
hand  soldering  technic  described  by  Angle  consists  in  the  use  of  a  pin 


Fig.  782. 


Fig.  783. 


Fig.  784. 

holder  (Fig.  785)  which  is  held  in  one  hand  and  the  arch  wire  sup- 
ported in  the  other  by  a  pin  vise  which  will  be  found  of  assistance  in 
holding  the  arch  wire  firmly. 


Fig.  785. 

Owing  to  the  difficulty  of  placing  a  piece  of  solder  between  the  pin 
and  the  arch,  the  use  of  solder  rings  has  displaced  other  methods  of 
manipulation.  One  of  these  rings.  Fig.  786,  is  sprung  on  the  fish-tail 
end  of  the  pin,  the  head  end  being  in  the  pin-holder,  and  the  pin  and  arch 


CONSTRUCTIVE   TECHNIC. 


863 


wire  held  in  approximation,  the  pin  at  the  properly  judged  angle  of 
inclination  to  perfectly  fit  the  tube,  and  the  solder  fused  into  pla(  e. 

To  still  further  prevent  inaccuracy  in  the  alignment  of  the  pin  paral- 
lel with  the  tube  that  is  to  receive  it,  and  to  get  the  exact  angle  of  inclina- 
tion, the  soldering  jig  (Fig.  787  A,  B,  C),  was  invented  by  Angle, 
assisted  by  Gough  and  Lane.  The  arch  wire,  resting  passively  in 
position  in  the  mouth,  is  firmly  held  in  the  vise  A  at  a  point  not  more 


as  B 


Fig.  786. 


Fig.  787 


than  a  half  inch  away  from  the  point  at  which  the  pin  is  to  be  sol- 
dered, the  copper  wire  B  is  clamped  into  a  hole  near  the  top  of  the  vise 
with  a  set  screw,  and  the  other  end  of  the  wire  bent  so  that  it  rests 
against  the  point  the  head  of  the  pin  will  occupy  when  in  place.  The 
proper  inclination  is  given  by  bending  the  copper  wire.  On  removing 
the  jig,  still  fastened  to  the  arch  wire,  from  the  mouth,  the  pin  carrier, 
C  .holding  the  arch  pin  with  hook  pointing  labially  and  a  ring  of  solder 


Fig.  788. 

in  place,  is  telescoped  over  the  end  of  the  copper  rod  in  exact  register 
for  the  pin  to  be  soldered  to  the  middle  section  when  adjusted. 

Another  method  of  soldering  these  delicate  arch  pins  in  place  is  the 
use  of  a  delicate  compound  clamp  (Fig.  788)  devised  by  the  author. 
The  arch  is  inserted  in  a  hole  of  the  same  diameter  in  the  upper  arm  of 
the  clamp,  where  it  is  held  by  friction.  The  middle  arch  section  is 
slipped  into  an  extra  spring  arm  on  the  lower  part  of  the  clamp,  where  it 
is  securely  held,  while  the  pin  is  adjusted  to  the  notch  in  the  arch  wire 
at  the  properly  judged  angle  of  inclination,  and  soldered.  If  the  angle 
of  inclination  is  incorrect  after  trial  in  the  mouth  it  is  easily  corrected 
on  readjustment  of  the  arch  wire  in  the  clamp  by  slightly  rotating 
the  clamp  on  the  arch  wire  while  the  solder  is  fused  at  the  base  of  the 
pin. 


864  ORTHODONTIA 


PART  XV. 
PLASTER  TECHNIC. 

Necessity  for  Accurate  Models. — The  primary  importance  of 
■diagnosis  in  the  consideration  of  the  possibilities  of  treatment  of 
malocclusion,  renders  it  necessary  that  accurate  models  of  the  teeth  and 
dental  arches  should  be  made  of  every  case  so  that  a  foreknowledge  of 
every  condition  of  malocclusion  and  of  every  special  pathological  indi- 
cation may  be  gained  by  a  careful  study  of  such  models. 

The  charts  of  Dr.  Hawley  for  arch  predetermination,  and  the  sym- 
metroscope  of  Dr.  Griinberg  were  both  designed  for  use  with  plaster 
casts  which  accurately  reproduce  the  dental  arches,  and  the  measure- 
ments taken  and  conclusions  drawn  from  these  methods  of  diagnosis 
would  otherwise  have  no  definite  value. 

Readings  from  Casts. — ^The  casts  of  each  dental  arch  in  occlusion 
should  represent,  to  the  minutest  degree,  the  exact  variation  of  the 
occlusion  from  the  normal,  the  depth  of  cusps  and  length  of  overbite 
the  compensating  curves. 

Separately  they  should  exhibit  all  the  fine  lines  of  the  anatomical 
structures  which  it  is  intended  they  should  copy,  such  as  the  rugae  and 
stipples  of  the  gum  tissue,  the  form  and  attachment  of  the  frenum 
labium,  the  height  and  width  of  the  palate,  abscess  fistulas,  and 
pathological  conditions  such  as  hypertrophy  of  the  gingivae,  the 
degree  of  development  of  the  arch  well  up  to  the  line  of  demarcation 
of  the  cheek  and  gum  tissue,  and  especially  the  perfection  or  imper- 
fection of  every  tooth  surface,  including  developmental  grooves  and 
inclined  planes,  and  the  facets  of  the  cusps,  which  latter,  to  the  ex- 
perienced eye,  tell  a  story  which  can  be  learned  in  no  other  way,  of  the 
articular  movements  of  the  mandible. 

Reference  to  the  model  during  the  treatment  of  a  case  is  of  value 
in  indicating  the  changes  in  growth  of  the  dental  arches,  since  it 
exhibits  the  exact  degree  of  arrested  or  deficient  development  at  the 
beginning  of  treatment,  and  comparative  measurements  taken  occa- 
sionally will  record  the  progress  in  a  given  case. 


PLASTER   TECHNIC. 


86s 


The  model  also  indicates  the  proper  relations  of  retaining  appli- 
ances upon  completion  of  the  treatment. 

A  collection  of  finely  made  models  serves  not  only  as  a  library 
of  reference  and  study,  but  also  as  an  accurate  indication  of  the 
individual  skill  of  the  operator,  both  in  the  making  of  the  models 
themselves,  and  in  the  perfection  of  treatment  which  they  exhibit. 

Medico-legally,  the  plaster  reproduction  of  the  teeth  in  the  model 
is  an  accurate  record  of  fact,  which  is  accepted  as  evidence  in  a  court 


Fig.  789. 

of  law,  thereby  ensuring  some  protection  to  the  operator  from  the 
unappreciative  and  dishonest  who  resort  to  questionable  methods  in 
the  evasion  of  their  just  obligations. 

Impression  Materials  and  Methods. — ^Plaster-of-Paris  has  long 
been  recognized  as  the  ideal  material  for  taking  accurate  impressions 
of  the  teeth,  casts  from  which  are  absolutely  accurate  in  detail  of  re- 
production, as  in  its  use  in  surgery,  its  reproduction  of  internal  or 
external  structural  anatomy  having  not  been  superseded  by  any  other 
material. 
55 


866  ORTHODONTIA. 

Angle  was  the  first  to  place  model  making  in  the  list  of 
the  arts  by  the  introduction  of  a  method,  which  in  its  main  char- 
acteristic, is  still  followed,  the  improvement  in  technic  and  detail 
which  have  been  suggested  by  others  in  the  same  field  being  here 
described. 

As  the  impression  in  plaster  will  reproduce  the  finest  lines  of  tooth 
surfaces,  care  should  be  taken  that  all  hard  and  soft  deposits  be 
removed,  and  the  teeth  thoroughly  cleaned  before  the  impression  is 
taken. 

The  Impression  Tray. — The  Angle  impression  trays,  illustrated 
in  Fig.  789,  are  especially  adapted  for  taking  full  impressions  of  either 
arch,  having  high  rims,  and  being  so  shaped  and  polished  that  they 
may  be  removed  soon  after  insertion  in  the  mouth  by  a  slight  manip- 
ulation, leaving  the  setting  plaster  in  the  mouth  to  be  sectioned,  frac- 
tured, and  removed  in  several  pieces.  ;  ^ 

Trays  should  be  selected  according  to  the  size  of  the  mouth,  large 
enough  to  allow  for  at  least  one-eighth  of  an  inch  of  plaster  between 
the  teeth  and  the  sides  of  the  tray,  which  will  admit  of  a  slight  bending 
for  such  adaptation. 


Fig.  790. 

These  trays  are  provided  in  graded  sizes  21,  21^,  22,  22^,  23,  and 
23^  in  the  upper  set,  and  in  corresponding  sizes  24  ,25,  26,  and  27  in 
the  lower  set. 

The  surfaces  of  the  impression  trays  should  never  be  scratched  nor 
indented,  as  any  marring  of  the  surface  prevents  easy  removal  of  the 
tray  from  the  impression  in  the  mouth.  It  will  be  found  an  economy 
of  time  to  replace  slightly  marred  trays  with  new  ones. 

Mixing  of  the  Plaster.— On  account  of  the  quick  setting  of  im- 
pression plaster,  the  use  of  salt  or  potash  for  hastening  this  process 
is  unnecessary  in  the  plaster  mix,  in  fact,  they  are  detrimental  to 
the  securing  of  a  perfect  impression  because  of  the  haste  necessary  in 
manipulation,  and  the  coarseness  of  crystallization  of  the  plaster, 
which  is  destructive  of  the  fine  lines  on  the  surface  of  the  impression. 
Distilled  water  at  a  temperature  of  about  70°  F.  is  preferred  for 
comfort  and  for  perfect  mixture  of  the  plaster. 

The  quantity  of  water  necessary  for  the  usual  mix  should  be  some- 


I 


PLASTER   TECHNIC.  867 

what  accurately  gauged,  and  the  plaster  gradually  sifted  in  until  it 
absorbs  the  water  completely,  when  it  is  ready  for  immediate  pouring 
into  the  tray  which  has  been  selected  of  a  litde  larger  size  than  the 
dental  arch  of  which  an  impression  is  desired. 

Only  the  best  impression  plaster  should  be  used,  French's  plaster 
as  furnished  by  the  depots  in  a  metallic  can  with  tightly  fitting  cover 
being  preferable,  as  it  may  be  kept  perfectly  clean  and  dry  in  this 
receptacle. 

Distribution  of  Plaster  in  the  Tray.— If  the  impression  is  to  be  of 
an  upper  arch,  the  palatal  portion  of  the  tray  should  not  be  covered 
with  the  plaster,  the  rest  of  the  tray  being  about  three  quarters  filled. 


Fig.  791. — (Rogers.) 

and  a  small  surplus  allowed  to  rest  upon  the  handle  to  be  forced  under 
the  lips.  If  necessary,  the  buccal  and  labial  spaces  may  be  first  filled, 
using  a  bone  or  glass  spatula  to  carry  the  plaster  to  place,  as  suggested 
by  Rogers. 

The  tray  is  then  inserted  in  the  mouth,  and  pressed  quickly  into 
position,  taking  care  that  the  teeth  are  about  equally  distant  from 
either  side  and  the  bottom  of  the  tray.  While  being  held  in  position 
with  the  middle  finger  of  the  left  hand,  the  surplus  plaster  may  be 
cleaned  from  the  tray  with  the  tweezers  and  cotton. 

The  impression  should  be  allowed  to  harden  until  it  will  fracture 
properly,  when  the  tray  should  be  renoved  by  exerting  a  slight  and 
uniform  downward  pressure  upon  the  handle,  after  which  surplus 
pieces  may  be  removed  from  the  mouth  with  the  tweezers  and  cotton. 


868  ORTHODONTIA. 

The  impression  should  next  be  grooved  vertically,  on  both  sides 
usually  over  the  cuspid  region,  with  a  form  of  knife  shown  in  Fig.  790, 
which  is  best  adapted  for  reversal  in  grooving  both  upper  and  lower 
impressions  without  danger  of  cutting  the  lips,  the  short  curved  blade 
being  admirably  shaped  for  skillful  manipulation. 

By  prying  from  the  bottom  of  one  of  the  grooves  with  this  same 
knife,  after  the  plaster  is  hard,  the  central  section  of  the  impression 
may  be  removed  easily,  and  the  two  buccal  portions  by  exerting  an 
outward  prying  motion  with  the  thumb  against  the  anterior  edge, 
leaving  the  palatal  portion  to  be  gently  pried  out  with  an  instrument. 


Fig.  792. —  (Rogers.) 

The  pieces  are  then  placed  in  a  small  box  upon  which  is  marked 
the  name,  date,  and  age  to  be  copied  later  on  the  index  record  of  the 
patient. 

The  lower  impression  differs  from  the  upper  only  in  the  detail  of 
the  manipulation  of  the  tray,  care  being  taken  not  to  allow  of  an  excess 
of  plaster  in  the  distal  ends  of  the  grooves. 

Figs.  791  and  792  represent  very  perfect  lower  and  upper  impressions 
of  the  teeth  after  the  fractured  pieces  have  been  assembled. 

Assembling  the  Impression. — The  fractured  pieces  should  be 
thoroughly  dried,  over  night  usually,  although  they  may  be  quickly 
dried  by  placing  them  upon  a  piece  of  tin  over  a  burner,  and  then 
assembled,  beginning  with  the  larger  'pieces,  adding  one  at  a  time,  and 
dropping  a  small  bead  of  hard  sticky  wax  upon  the  outside  of  the 
impression  at  intervals  of  about  one-quarter  of  an  inch  along  the  lines 


J 


PLASTER   TECHNIC,  869 

of  fracture,  as  illustrated  in  Fig.  793.  The  edges  of  the  fractured 
portions  should  be  cleaned  of  crumbled  pieces  before  uniting  them. 
Occasionally,  it  will  be  of  advantage  to  replace  broken  pieces  in  the 
tray,  but,  as  a  rule,  better  results  are  obtained  without  doing  so. 

Varnishing  the  Impression. — After  being  properly  assembled, 
the  impression  should  be  varnished  with  a  solution  of  shellac  allowed  to 
dry  for  half  an  hour,  and  then  varnished  with  a  solution  of  sandarac, 
repeating  the  last  varnish  again  in  another  half  hour.  These  solutions 
are  so  thin  that  they  leave  a  scarcely  perceptible  coating  upon  the  surface 
of  the  impression,  although  rendering  it  easily  separated  from  the  cast, 
the  shellac  giving  a  color  line  to  cut  to,  and  filling  the  pores,  and  the  san- 
darac simply  filling  over  the  surfaces  of  the  pores,  so  that  capillary  attrac- 
tion cannot  take  place  when  the  impression  is  filled.* 


Fig.  793. 

Filling  of  the  Impression. — The  varnishes  being  thoroughly 
dried,  the  impression  may  be  placed  in  a  basin  of  clean  water  to 
become  infiltrated  from  the  outside  with  water,  while  the  plaster  is 
being  mixed  ready  for  its  pouring. 

A  slow  setting  model  plaster  is  preferred  for  a  hard  cast,  although 
many  have  used  the  impression  plaster  with  good  results,  its  fineness 
giving  a  very  beautiful  surface. 

The  plaster  should  be  mixed  in  the  same  manner  as  for  the  impres- 
sion, and  a  small  portion  placed  in  the  heel  of  the  impression  and 
carefully  worked  forward  from  one  tooth  cusp  to  another  with  the 

♦According  to  Angle,  these  solutions  should  be  prepared  in  the  proportions  of  i  ounce 
of  shellac  to  3J  ounces  of  alcohol,  for  the  shellac  varnish  and  i  ounce  of  sandarac  to  2^ 
ounces  of  alcohol  for  the  sandarac  varnish. 


SjO  ORTHODONTIA. 

camel's  hair  brush,  until  all  the  cusps  are  perfectly  filled,  when  the 
remainder  of  the  impression  may  be  quickly  filled  with  the  plaster 
knife,  which  should  be  of  platinoid  so  as  to  prevent  rusting. 

A  portion  of  plaster  should  be  placed  upon  a  clean  glass  slab  and  the 
impression  inverted  thereupon,  and  pressed  down  so  that  the  anterior 


Fig.  794. 

edge  is  within  one-half  inch  of  the  glass  surface,  preserving  a  parallel 
between  the  bottom  of  the  impression,  or  tray,  if  present,  and  the  hori- 
zontal line  of  the  glass  slab,  as  in  Fig.  794.  The  surplus  plaster  is 
then  trimmed  away  with  the  plaster  spatula,  and  the  plaster  allowed  to 
harden  for  about  twenty  minutes  before  it  is  ready  to  be  again  touched. 


Fig.  795. 

Sectioning  and  Removal  of  Impression. — The  impression  is 
more  easily  removed  from  the  cast  within  half  an  hour  from  the  time 
of  its  filling,  as  it  then  contains  the  greatest  amount  of  moisture. 
However,  it  should  be  immersed  in  water  again  for  a  few  seconds  to 
still  further  soften  the  surface  before  attempting  to  separate  the  im- 
pression from  the  cast. 


PLASTER   TECHNIC. 


871 


The  small  beads  of  wax  should  be  cut  o£F  and  the  portion  of  the 
cast  extending  above  the  impression  roughly  trimmed  with  the  cast 
trimmer,  shown  in  Fig.  798,  to  approximately  the  shape  to  which  it  is 
intended  to  conform  when  finished. 

The  sides  of  the  impression  may  then  be  vertically  and  horizontally 


Fig.  796. 

grooved  as  in  Fig.  775  using  ihe  smaller  knife  shown  in  Fig.  796,  a 
method  suggested  by  Rogers. 

The  depth  of  the  grooves  should  not  be  greater  than  the  brown 
color  of  the  shellac  varnish,  which  appears  as  the  bottom  of  the  groove 
approaches  the  surface  of  the  cast. 


Fig.  797. 

Beginning  at  the  heel  of  the  impression,  one  section  at  a  time  is 
pried  away  with  the  grooving  knife,  removing  the  upper  sections  first. 

The  author  prefers  to  shave  down  the  surface  above  the  occlusal 
edges  of  the  teeth  until  the  brown  color  above  the  prominent  tooth 
cusps  begins  to  appear  before  making  the  vertical  and  horizontal 


872  ORTHODONTIA. 

grooves  in  most  cases,  and  many  times  a  single  vertical  groove  in  the 
region  of  the  cuspid  on  each  side  is  sufficient  for  the  easy  removal  of 
the  sections  extending  from  these  grooves  to  the  heel  of  the  impression. 
The  front  of  the  impression  should  always  be  horizontally  grooved  to 
prevent  accidental  injury  to  the  incisors  in  removal. 

Oftentimes,  the  lines  of  fracture,  which  may  run  along  the  cusp 
surfaces  of  the  teeth,  will  facilitate  the  removal  of  the  impression  very 
materially.  It  will  almost  always  be  found  necessary  to  groove  the 
lingual  surface  of  the  impression  upon  a  lower  cast  before  it  is  possible 
to  remove  it.  In  an  upper  impression  also,  it  will  often  be  necessary  to 
make  a  groove  lengthwise  of  the  palatal  section  of  the  impression  and 
then  remove  one-half  of  the  palatal  portion  at  a  time. 

It  is  well  to  mark  on  the  surface  of  an  impression,  before  pouring, 
the  positions  of  teeth  in  labial  or  lingual  occlusion,  to  prevent  marring 
them  in  the  sectioning  process. 

Trimming  of  the  Model.— After  the  removal  of  the  casts  from  the 
impressions,  they  should  be  moistened  in  clean  water,  and  then  roughly 

trimmed  to  the  geometrical  outlines 
which  have  been  accepted  as  most 
artistic  and  harmonious  for  each,  the 
base  for  the  lower  cast  being  trimmed 
to  the  inside  pattern  in  Fig.  797  with 
slightly  rounded  front,  and  the  up- 
FiG.  ^^?,.-{Eastman  Kodak  Co.)         P^r  cast  to  the  outside  pattern  of 

this  figure,  being  precisely  similar 
to  the  upper  outline,  except  for  the  pointed  front,  which  not  only  affords 
extension  for  a  frenum  labium  of  varying  size,  but  gives  a  pleasing  and 
distinctive  variation  to  the  capital  of  the  model. 

From  a  geometrical  standpoint,  the  two  patterns  present  the  forms 
of  two  triangles  with  equiangular  basal  angles  which  have  been  clipped 
by  lines  parallel  to  the  lateral  lines  of  the  triangle  from  one-quarter  to 
one-half  an  inch  in  length,  and  the  anterior  angle  cut  across  from  inter- 
sections directly  over  the  cuspids  on  the  lateral  dimensions  by  the  curve 
on  the  lower  cast  and  the  obtuse  angle  on  upper  cast. 

Constructed  upon  these  lines,  the  base  and  capital  present  almost 
similarly  formed  designs,  with  the  long  sides  of  the  triangles  parallel 
to  the  buccal  surfaces  of  the  bicuspids  and  molars,  and  the  median 
line  of  the  anterior  sections  equidistant  from  the  cuspids  except  where 
there  is  much  divergence  of  the  anterior  teeth  mesially  or  distally,  when 
the  median  line  of  the  capital  may  be  made  to  coincide  with  the  central 
line  of  the  cast  as  indicated  by  the  rugae. 


PLASTER   TECHNIC. 


873 


This  rough  trimming  may  be  done  with  great  accuracy  and  little 
effort  by  cutting  the  vertical  and  horizontal  planes  with  a  cast  trimmer, 
designed  like  the  print  trimmer  shown  in  Fig.  798,  but  modified  for  plaster 
work  by  being  provided  with  a  brass  covered  base  and  a  high  beveled 
removable  steel  blade,  which  is  kept  sharpened  to  the  edge  of  a  fine 
chisel. 


Fig.  799. — S  B,  shooting  board.     P,  plane.  ^ 

The  vertical  planes  on  the  lower  cast  should  be  cut  first  to  within  a 
quarter  of  an  inch  of  the  perfected  pattern,  and  then  the  base  of  the  cast 
trimmed  so  that  it  is  parallel  to  the  plane  of  occlusion. 

In  cases  in  which  the  compensating  curves  are  very  marked,  the 
plane  of  occlusion  might  be  represented  by  the  plane  passing  through 


Fig.  800. —  {Rogers.) 

or  touching  the  tips  of  the  distal  cusps  of  corresponding  molars  on 
either  side  and  the  edges  of  the  central  incisors. 

The  vertical  planes  are  next  corrected  and  finished  to  almost  the 
exact  final  pattern,  the  finishing  touches,  however,  being  reserved  for 
the  plaster  plane. 


874  ORTHODONTIA. 

Northcroft  has  invented  an  accurate,  labor  saving  plaster  plane 
which  runs  on  a  shooting  board  provided  with  an  adjustable  angle  piece, 
with  which  to  accurately  produce  the  several  vertical  planes  on  the  case 
(see  Fig.  799).     A  step  is  also  a  convenient  part  of  the  shooting  board, 


Fig.  801. 

since  it  facilitates  the  cutting  of  the  anterior  planes  without  danger  of 
injury  to  the  incisors.  The  author  prefers  the  steel  blade  to  one  of 
phosphor-bronze  as  the  former  retains  its  keen  edge  for  a  much  longer 
itme  than  the  blade  of  a  rust  proof  alloy  which  has  no  advantage  exceut 
its  freedom  from  rusting. 


Fig.  802. 


The  thickness  of  the  mechanically  finished  portion  of  the  cast  is 
determined  somewhat  by  the  size  of  the  anatomical  portion,  but  should 
seldom,  in  a  cast  of  the  permanent  teeth,  be  less  than  one-quarter  of  an 
inch  in  the  height  of  the  anterior  vertical  planes. 


PLASTER   TECHNIC.  875 

After  the  lower  cast  is  properly  aligned  and  finished  to  form  the 
base  of  the  model,  the  upper  case  is  cut  to  approximate  the  inside  pat- 
tern shown  in  Fig.  797,  and  is  then  placed  in  occlusion  with  the  base  so 
that  all  surfaces  and  angles  of  the  capital  may  harmonize  with  those  oi 
the  base. 

The  upper  surface  of  the  capital  should  then  be  planed  down  until  it 
is  parallel  with  the  horizontal,  unless  it  is  too  thin,  in  which  case  the 
required  thickness  may  be  secured  by  inversion  of  the  occluded  model, 
capital  downward,  upon  a  small  quantity  of  fresh  plaster  upon  a  glass 
slab,  it  being  necessary  to  manipulate  the  inverted  occluded  casts  so  that 
the  base  of  the  model  will  be  in  the  horizontal  plane  as  judged  by  the 
eye. 

The  planes  of  the  sides  of  the  capital  should  be  all  vertical  planes, 
and  the  posterior  vertical  planes  should  coincide,  if  possible,  giving 


Fig.  S03. 

an  accurate  guide  to  the  occlusion  if  it  should  not  have  been  marked 
on  the  cusps,  as  shown  in  Fig.  800. 

A  slight  bevel  cut  around  the  entire  edge  of  both  capital  and  base 
adds  to  the  artistic  finish,  and  preserves  the  model  from  chipping  of 
otherwise  sharp  angles  in  handling. 

The  mechanically  finished  surfaces  of  the  model  may  be  made  still 
smoother  by  finishing  with  a  fine  broad,  flat,  jeweler's  file  after  the 
casts  are  perfectly  dry. 

The  trimming  of  the  capital  and  base  according  to  certain  definite 
geometrical  lines,  is  not  only  the  most  artistic  and  best  proportioned 
conformation  of  otherwise  ungainly  reproductions,  but  it  serves  the 
very  practical  purpose  of  a  standard  for  uniformity  which  enables 


876  ORTHODONTIA. 

the  busy  orthodontist  to  more  quickly  and  consecutively  follow  out 
the  definite  rules  for  obtaining  esthetic  effects  than  by  the  old  and  less 
accurate  methods  of  model  trimming. 

The  anatomical  portions  of  the  model  should  represent  perfectly 
the  parts  which  they  are  intended  to  reproduce,  and  will  be  perfect  in 
proportionate  degree  to  the  care  which  has  been  taken  in  the  consecutive 
steps  of  their  production. 

Marking  and  Numbering  of  Models. — When  such  infinite  pains 
have  been  taken  and  artistic  skill  used  in  securing  a  beautiful  and  har- 
moniously proportioned  model,  it  should  not  be  ruined  by  marking  the 
name  of  the  patient,  the  age  and  the  date  of  commencement  of  treatment 
upon  every  surface  of  the  mechanical  portion,  as  is  often  done. 

Each  model  needs  its  serial  number  for  the  cabinet,  which  may  be 


Fig.  804. 

stamped  with  India  ink  upon  the  labial  surface  of  the  base  ofthe  model 
and  the  posterior  surface  of  the  capital,  leaving  all  other  surface  of  the 
model  void  of  any  marks  whatever. 

In  numbering,  it  is  advisable  to  keep  the  same  serial  number  for  the 
before  treatment  and  after-treatment  models,  distinguishing  consecu- 
tively made  models  by  progressive  alphabetical  lettering  such  as  105a, 
1056,  105c,  etc. 

Repairing  Defects. — If  a  good  impression  has  been  first  secured 
and  the  detail  of  assembling  of  the  fractured  portions,  the  varnishing, 
pouring  and  removal  of  the  cast,  carried  out  according  to  the  instruc- 
tions previously  given,  very  little,  if  any,  retouching  will  be  necessary 
upon  the  anatomical  portion  of  the  cast. 


PLASTER    TECHNIC.  877 

But,  at  least,  the  amateur  is  liable  to  get  a  few  air  bubbles  or  other 
imperfections  upon  the  surface  of  some  of  his  casts,  which  will  need 
some  little  skill  in  the  use  of  the  camel's  hair  brush  to  render  them  un- 
noticeable. 

Air  bubbles  and  other  indentations  such  as  are  often  caused  by 
the  knife  blade  in  separating,  are  filled  with  plaster  in  the  following 
manner:  first,  moisten  the  cast  or  the  portion  of  it  needing  repair, 
then  with  the  camel's  hair  brush  carry  a  small  quantity  of  very  thinly 
mixed  plaster  into  the  bottom  of  the  air  bubble,  repeating  until  it  is  a 
little  more  than  full,  when  the  correct  contour  is  obtained  by  a  twisting, 
wiping  motion  of  the  slightly  moistened  brush  over  the  surface. 

Fig.  801  represents  an  upper  cast  which  has  a  considerable  number 
of  air  bubbles  caused  by  carelessness  in  pouring  the  impression,  and 
the  loss  of  contour  of  some  of  the  cusps  of  the  teeth  makes  the  cast 
rather  unsightly.     A  little  practice  with  the  brush  and  plaster  will  en- 


FiG.  805. 

able  the  operator  to  restore  the  contour  as  in  Fig.  796,  which  illustrates 
the  same  cast  as  in  the  previous  figure  after  it  has  been  treated  by  this 
method. 

Fractured  teeth  and  cusps  are  somewhat  differently  treated,  since 
it  is  almost  impossible  to  force  plaster  of  any  consistency  into  a  crack 
such  as  is  visible  on  adjusting  two  fractured  portions  of  a  tooth  together. 

One  of  the  surfaces  of  the  fracture  should  be  carved  out  to  a  cres- 
cent shape,  not  touching  the  periphery  of  the  cusp  or  tooth,  however, 
as  this  will  be  needed  to  place  it  in  register,  after  which  the  groove 
thus  made  may  be  filled  with  thin  plaster  in  the  same  manner  as 
the  air  bubbles.  This  method  of  uniting  fractured  pieces  is  very 
artistic  in  effect  and  the  result  permanent,  being  preferred  to  cement 
which  causes  a  line  of  demarcation  which  is  especially  noticeable 
in  a  photograph. 

Fig.  803  represents  a  badly  fractured  cast,  the  right  cuspid,  both 
centrals,  and  the  left  lateral  having  been  accidentally  broken  off. 
Fig.  804  exhibits  the  same  cast  after  the  fractured  pieces  have  been 
reunited  by  this  method.  The  right  central  was  restored  in  contour 
entirely  with  the  brush,  since  the  fractured  portion  was  lost.  It  is 
possible  to  restore  even  such  a  delicate  part  as  the  frenum  labium, 


878  ORTHODONTIA. 

which  seldom  escapes  fracturing  in  separating,  but  a  knowledge  of  the 
minute  anatomy  of  the  parts  is  essential  to  the  attainment  of  artistic 
and  esthetic  results  in  attempting  the  reproduction  of  lost  portions  of 
the  anatomical  part  of  the  cast. 

The  lines  of  fracture  of  the  impression  are  reproduced  in  the  cast, 
and  should  be  carefully  burnished  down  with  the  spoon  blade  of  a 
wax  spatula  adapted  for  the  purpose,  such  as  is  illustrated  in  Fig. 
805,  being  an  S.  S,  White  No.  7  double  bladcd  spatula. 

The  smaller  blade  may  be  sharpened  upon  one  edge  to  be  used  in 
removing  any  superfluous  plaster  contiguous  to  the  festoons  of  the  gums 
on  the  cast,  also  in  carving  out  any  surplus  plaster  from  the  embrasures 
of  adjoining  teeth,  and  the  cusps  of  bicuspids  or  molars  which  are  im- 
perfect. Any  attempt  at  carving  beyond  the  shaving  of  superfluous 
plaster,  quickly  shows  its  artificiality  and  should  be  avoided. 

PART  XVI. 
PROPHYLAXIS. 

Mouth  Hygiene. — During  the  wearing  of  appliances  in  the  mouth 
the  greater  liability  of  food  collecting  around  the  teeth,  and  the  lessened 
activity  of  the  oral  fluids  in  performing  their  natural  cleansing  function 
makes  it  imperative  that  especial  prophylactic  measures  be  instituted. 

The  patient's  teeth  should  be  thoroughly  cleaned  before  the  com- 
mencement of  operations,  and  during  treatment  instructions  should  be 
given  for  the  frequent  use  of  the  tooth  brush,  preferably  after  each  meal 
and  upon  arising. 

A  tooth  brush  with  one  row  of  bristles  is  much  better  adapted  to 
cleansing  above  and  below  the  expansion  arch  than  the  brush  with 
several  rows  of  bristles. 

Frequently,  the  removable  parts  of  the  appliance  should  be  removed, 
and  the  teeth  cleansed  carefully  with  pumice  or  washed  with  alcohol.  It 
is  of  still  greater  benefit  to  have  the  patient  referred  back  to  the  family 
dentist  for  more  detailed  prophylactic  treatment,  especially  with  the 
orange  wood  stick  and  pumice. 

Care  of  Ligatures. — Silk  ligatures  should  be  frequently  renewed  as 
they  readily  absorb  the  food  products  and  become  active  agents  in  the 
formation  of  "retention  centers."  If  silk  Hgatures  are  saturated  in 
campho-phenique,  and  kept  tightly  sealed  in  glass  tube  containers, 
they  will  remain  free  from  the  products  of  food  decomposition  for  a 
much  longer  period. 


PROPHYLAXIS.  879 

Pneumatic  Sprays. — The  compressed  air  spray  in  connection  with 
antiseptic  mouth  washes,  is  most  beneficial  as  a  prophylactic  measure, 
being  used  at  each  visit  of  the  patient  throughout  the  treatment. 

Ferris  has  recommended  a  combination  of  sprays  which  have  certain 
peculiar  reactions  which  make  them  of  exceptional  value,  being  both 
chemical  and  mechanical  in  their  action. 

The  first  of  the  series  of  sprays  contains  the  active  agent  iodine 
in  combination  with  potassium  iodide,  which  acts  germicidally  to  de- 
stroy the  spores  and  parent  cells  in  albuminous  material,  which  it  read- 
ily penetrates,  staining  the  bacterial  plaques  so  that  they  are  visible  upon 
tooth  surfaces. 

The  second  spray  consists  of  a  starch  solution  which  absorbs  the 
stained  plaques,  forming  a  flocculent  precipitate,  which  is  readily 
removed  by  the  third  spray  which  is  a  simple  solution  of  sodium  car- 
bonate, having  the  power  to  decolorize  the  precipitate  previously 
formed,  at  the  same  time  freeing  the  surfaces  of  the  teeth  still  further 
by  saponifying  the  fats. 

The  antiseptic  and  beneficial  value  of  these  sprays,  used  consecu- 
tively, is  not  excelled  by  any  other  at  present  known  methods  of  oral  an- 
tisepsis. 

The  series  of  sprays  are  given  below  in  the  order  of  their  use,  it 
being  necessary  to  have  separate  nozzles  for  each  spray,  which  also 
must  be  used  at  the  temperature  noted  in  order  to  have  the  desired 
efifect. 

I. 

I^ — lodini,  gr,  xxx. 

Potassii  iodidi,  gr.  xix 

Aquae  dest.  ad.  q.  s.  5  iv. 

Sig. — To  be  used  in  spray  under  high  pressure 
at  the  temperature  of  98°  F. 


II. 

I^ — Starch,  gr.  xxxviii 

Aquae  menth.  pip.  5    iv. 

Oleum  menth.  pip.  rr\  xx. — M. 

Sig. — To  be  used  at  the  temperature  of  115°  F.  In  makin  ■ 
this  compound,  mix  the  first  two  ingredients  and  let  stand  for 
five  minutes,  then  boil  for  five  minutes,  then  add  the  flavoring. 


III. 
I^ — Sodii  carb.,  gr.  xxxviii. 

Aquae  gaultheria,  5    iv. 

Olei  gaultheria,  n\   xxx. — M. 

Sig. — To  be  used  at  the  temperature  of  115°  F, 


88o  ORTHODONTIA. 

Tonic  Mouth  Wash. — Ferris  also  recommends  a  tonic  mouth 
wash  to  give  tone  to  the  mucous  tissues,  and  to  develop  normal 
secretion  during  abnormal  conditions.     The  formula  is  as  follows: — 

Formula  No.  IV. 
I^ — Hydronaphthol, 

Menthol,  aa  gr.  xxx. 

Oil  gaultheria, 

Oil  cassia,  aa  n^  iv. 

Alcohol,  5  X. 

Tinct.  capsicum,  3  i 

Aquae  dest.,  ad  q.  s.  5  xx. 

M.     Sig. — Teaspoonful  to  half-glass  hot  water 
five  times  dail 


INDEX. 


Guide  to  the  Index. — The  index  has  been  arranged  with  a  view  to  direct  the  reader  to  his  subject 
without  delay.     All  readers  do  not  think  of  the  same  subject  matter  in  the  same  form,  therefore  the 
same  subject  will  be  found  indexed  in  various  forms.    For  instance: 
"Preparation  of  cavities:" 

"for  fillings,  i6i" 
"Cavities:" 

"preparation  of,  for  fillings,  i6i" 
"Fillings,  preparation  of  cavities  for,  i6i" 
Where  a  —  appears  before  a  line  it  indicates  that  the  indexed  line  relates  to  the  sub-heading 
above  it. 


Abnormal  arch  development,  631 

frenum  labium,  649 

operation  for,  763 
Abscess,  acute  alveolar,  360 

chonic  alveolar,  362 

pericemental,  370 

pocket,  secondary,  369 

with  sinus,  364 

without  sinus,  363 
Absorbed  root,  368 
Absorbents,  the  use  of,  161 
Accessories  to  the  plain  band,  856 
Adaptation  of  the  arch,  699 
Adenoids,  64J 
Adjusting  the  arch  wire  and  pins.  731 

the  rubber  dam,  152 
Adjustment  of  anchor  clamp  bands,  706 
Adventitious  growths,  removal  of,  643 
After-pains  of  extraction,  454 
After-treatment  of  extraction,  455 
Alveolar  hemorrhage  from  the  extraction 

of  a  tooth,  452 
Amalgam,  244 
Amalgam  and  cement,  256 
Analgesics,  226 

Anatomy  of  the  human  teeth,  i 
Anatomical  parts  of  the  teeth,  2 
Anchorage,  679 

anterio-posterio     re-enforcement     of 
anchorage,  686 

conservation  of,  693 

first  molar,  680 

fixed  appliances,  693 

intermaxillary,  687 
uses  of.  689 

mechanical  requirements  of,  681 

occipital,  689 

simple,  683 

stationary,  683 

summary  of  principles,  695 
Anchor  clamp  bands,  adjustment  of,  705, 
706,  708 

teeth,  bodily  control  of,  669 

tubes,   alignment   of,    bucco-lingual, 
707 
Anesthesia,  local,  393 

56  88x 


Anesthetization     and     devitalization    of 
pulps,  32s 
for  removal  of  pulps,  326 
Anesthetizing  the  pulp,  method  of,  415 
Angle  of  the  tooth,  2 
Angle's  classification,  651 
Anodynes,  226 
Antagonizing  spurs,  838 
Anterior  and  posterior  arch  retention,  832 
Antrum,  369 
Apex,  2 

Apical  foramen,  2 
Application  of  principles,  696 

of  the  Roentgen  ray  to  dentistry,  541 
Appliances : 

choice  of  metals  for  (orthodontia), 

848 
efficiency  of  (orthodontia),  692 
materials  for  construction  of  (ortho- 
dontia), 848 
Approximation  of  parts  to  be  soldered,  853 
Arch: 

expansion,  696 
— divided,  698 
— threadless,  698 
— variety  in  form,  697 
integrity  preservative  forces  of,  613 
predetermination,  657 
retainer,  lingual,  833 
Arches: 

Case  reciprocating,  691 
malrelation  of.  651 
of  temporary  teeth,  605 
Area  of  den  to-facial  inharmony,  618 
Arrangement   of   light   in   the  operating 

room,  85 
Arrested  developmental  conditions  in  the 

arches,  early  treatment  of,  735 
Arsenical  poisoning,  340 
Articulation,  613 
Artificial  roots,  484 
Asepsis  in  the  operating  room,  89 
Assembling  the  impression  (orthodontia), 
868 
parts  of  molar  clamp  band  (ortho- 
dontia), 859 


882 


INDEX 


Assistants  in  the  office,  526 
Associated  anatomical  structures,  devel- 
opment of,  615 
Auxiliary  lock  pins,  733 

Badly  decayed  root,  359 
Band: 

accessories  to  the  plain,  856 
assembling  parts  of  anchor  clamp,  859 
construction  of  the  plain  anchor,  857 
Magill,  854 
removing  plier,  709 
soldering  the,  855 
Bands,  plain,  854 
Beauty,  physical  relations  of,  617 
Bending  of  loops,  731 
Bibs,  160 
Bicuspids: 

lower  first,  27 

— buccal  surface,  27 
— cervical  margin,  29 
— distal  surface,  29 
— lingual  surface,  27 
— mesial  surface,  29 
— occlusal  surface,  27 
— pulp  cavity,  30 
— root,  30 
second,  30 
upper  first,  19 

— buccal  cusp,  19 
— buccal  surface,  20 
— cervical  margin,  23 
— distal  surface,  22 
— lingual  surface,  21 
— mesial  surface,  22 
— occlusal  surface,  19 
— pulp  cavity,  23 
— root,  23 
second,  24 
Bilateral  expansion  of  the  dental  arch,  718 
infra-occlusion     of     bicuspids     and 
molars,  656 
Blood-vessels  of  the  pulp,  83 
Blowpipe,  the  Young,  850 
Bodily  control  of  anchor  teeth,  669 
Bon  will's  diagram,  658 
Bromids,  226 
Buccal  cavities,  272 

Buccal  tubes  on  anchor  clamp  band,  860 
Bucco  lingual  alignment  of  anchor  tubes, 

700 
Burs,  185 

Cabinet,  the  dental,  91 

Calculus,  109 

Capping  the  pulp,  320 

Card  system,  532 

Caries,  pathology  of  dental,  119 

Case  reciprocating  arches,  691 

Casualties  attending  tooth  extraction,  451 

Causes  and  treatment  of  dbcolorations  of 

teeth,  375 
Cavities : 

division  of,  168 

examination  of  teeth  for  discovery  of, 

131 
fissure,  170 


Cavities: 

instruments  for  preparation  of,  182 
management  of  large  proximo-occlu- 
sal  in  pulpless  bicuspids,  217 
large,  in  pulpless  molars,  217 
nomenclature,  165 

of  internal  parts  of,  167 
preparation    of,    in    bicuspids    and 
molars    involving    the    occlusal 
surface,  212 
— buccal  and  labial,  272 
— for  fillings,  165 
— for  inlays,  271 

— for  restoration  of  incisal  tips,  276 

preparation  of  simple  proximal  cav  - 

ties  in  incisors  and  cuspids,  274 

— in  occlusal  surfaces  of  bicuspids 

and  molars,  279 
— involving  the  proximal  and  oc- 
clusal surfaces  of  bicuspids  and 
molars,  277 
— proximal  cavities  involving  the 

incisal  angle,  274 
— proximal  in  incisors  and  cuspids 
involving  incisal  angle,  202 
steps  in  formation  of,  168 
Cement,  250 

for  inlays,  292 
Cemental  fusion  of  roots,  451 
Cementoblasts,  83 
Cementum,  73 
Central  incisor,  lower,  10 

upper,  3 
Cervical  clamps,  158 
Characteristics  of  normal  occlusion,  611 
Chemical  constituents  of  enamel,  63 

— composition  of  saliva,  no 
Chemistry  of  pulp  decomposition,  349 
Children's  teeth,  treatment  of,  385 
Chisels,  183 
Chloroform,  226,  227 
Choice  of  metals  for  appliance  (orthodon- 
tia), 848 
Chronic  alveolar  abscess,  362 
Clamp  bands,  adjustment  of  anchor,  705 
Clamps,  157 

Classification  of  cavities,  166 
chart  (orthodontia),  652 
malocclusion,  651 
Closing  up  spaces  between  incisors,  715 
Coagulating  agents,  355 
Cocain,  224 

hydrochlorid,  402 
Cold,  221 
ComlDination  filings,  255 

amalgam  and  cement,  256 
cement  and  gutta-percha,  257 
gold  and  amalgam,  256 
gold  and  cement,  256 
gold  and  tin,  256 
platinum  and  gold,  255 
Comparative  measures  of  resistance  (or- 
thodontia), 679 
Complications    incident    to    removal    of 

pulp,    338  .  f  T. 

in  treatment  after  extraction  of  teeth, 

814 


INDEX 


883 


Conditions  necessitating  removal  of  pulp, 

3.25 
Conservation  of  anchorage,  693 
Construction  of  complicated  retaining  ap- 
pliances, 861 
Construction  of  gold  inlays,  305 

difficult  cavities  filled  by  the  Taggart 
method,  309 

posts  for  cast  gold  inlays,  311 
Co-ordination  of  functions,  616 
Corrected  radius  (orthodontia),  663 
Correction   of   lines   of  exerted   force  in 

expansion  arch,  700 
Cotton  for  separating,  139 
Crown,  2 

Curve  of  Spec,  614 
Cuspid,  elevation  of  (orthodontia),  715 

extrusion  of,  715 
Cuspid,  the  lower,  1 7 

cervical  margin,  18 

cusp,  18 

distal  surface,  18 

labial  surface,  17 

lingual  surface,  18 

mesial  surface,  18 

pulp  cavity,  18 

root,  18 
Cuspid,  the  upper,  14 
Cusps,  2 
Cutting  of  the  flap,  480 

Daily  records,  528 
Deciduous: 
arch,  830 
cuspids,    results    of    extraction    of, 

808 
laterals,  results  of  extraction  of,  808 
lower  central  incisors,  57 
lower  cuspid,  58 
first  molar,  58 
lateral  incisor,  57 
second  molar,  59 
molars,  results  of  extraction  of,  810 
teeth,  materials  for  filling,  387 
premature  loss  of,  647 
prolonged  retention  of,  646 
pulps  and  abscesses  in,  366 
upper  central  incisor,  54 
cuspid,  55 
first  molar,  56 
,  lateral  incisor,  55 
second  molar,  57 
Decomposition  of  the  pulp,  349 
Deductions  from  early  symptoms  of  de- 
veloping malocclusion,  625 
Definition  of  matrix,  259 
Dental: 

cabinet,  91 
caries,  119 
engine,  185 
pulp,  76 
Dentin,  69 

histological  constituents  of,  69 
treatment  of  sensitive,  219 
Dento-facial  orthopedia,  617 
Denture,  normal  human,  i 
Denuded  end  of  root,  367 


Deposits,  107 

removal  of,  114 
serunaal,  112 
Designation  of  malpositions  of  teeth,  651 
Details  as  to  manipulation  of  matrix,  264 
Development    of    associated    anatomica 

structures,  615 
Developmental  spaces  (orthodontia),  606 
Deviation  of  the  nasal  septum,  640 
Devitalization  of  dental  pulp,  334 
Diagnosis: 

class  II,  765 
class  III,  789 
class  IV,  805 
orthodontia,  649 
pyorrhea,  493 
radiographic,  666 
Diagram,  Dr.  Bonwill's,  658 

Dr.  Hawley's,  658 
Direction  of  growths  of  dental  arches,  606 
Discolorations  of  teeth,  causes  and  treat- 
ment of,  375 
Discomfort  in  mastication,  388 
Disease  (orthodontia),  631 
Dislocation  of  lower  jaw,  451 
Distal  movements  of  molars,  723 
Distance  between  holes  in  rubber  dam,  151 
Distribution  of  plaster  in  the  tray  (ortho- 
dontia), 867 
Divided  expansion  arc,  689 
Division  of  teeth  and  cavities,  168 
Double  resection  of  the  mandible,  801 
Drilling  of  the  socket,  480 
Drug  irritants,  343 
Dynamics,  668 
arch: 

— expansion,  676 
divided,  677 
double,  679 
gauge  of,  676 
production  of  force,  677 
— sectional,  677 

economy  of  force,  679 
contraction  of  silk,  675 
definition,  668 

effect  of  force  on  tooth  movement,  668 
elasticity  of  flexion,  671 
— of  rubber,  673 
— of  stretching  of  soft  wire,  675 
— of  torsion,  672 
elementary  force-producing  machines, 
670 
— jackscrew,  671 
— screw,  670 
— spring,  671 
— traction  screw,  671 
interdental  elastic  force,  673 
intermaxillary  force,  674 
lever,  672 
movements,  669 
— bodily,  669 
— extruding,  670 
— inclination,  669 
— intruding,  670 
— rotating,  670 
requirements  in  orthodontia,  668 
wheel  and  axle,  673 


884 


INDEX 


Early  treatment  of  arrested  developmen- 
tal conditions  in  the  arches,  735 
Efficiency  of  appliances  (orthodontia),  692 
Electric  current,  221 

furnace,  302 
Electrical  units  of  measurements,  601 
Elevation  of  cuspid  (orthodontia),  715 
Employment  of  matrix  for  gold  restora- 
tions, 261 
Enamel,  62 

chemical  constituents  of,  63 

rods,  64 

strength  of,  69 

wall,    proper    bevel    and   polish   of, 
178,  201 
Encystment  of  root,  368 
Engine,  the  dental,  185 
Environment  (orthodontia),  627 
Epithelial  structures,  83 
Erosion,  307 

treatment  of,  515 
Erosions,  no 
Eruption  of  the  teeth,  428 
Escape    of   a   tooth   into    the   larynx   or 

pharynx,  451 
Escharotics,  222 
Establishing  sinus,  365 
Ether,  226 

Ethyl  chlorid,  226,  399 
Etiology: 

and  diagnosis  of  class  I,  738 

and  diagnosis  of  class  II,  765 

and  diagnosis  of  class  III,  789 

orthodontia,  625 

pyorrhea  alveolaris,  487 
Eugenol,  225 
Examination  of  teeth  to  discover  cavities, 

131 

cleanliness,  132 

concluding  notes,  134 

conditions  for  examination,  132 

diagnosis,  131 

dryness,  132 

gingival,  131 

lines  of  union,  131 

marginal,  132 

physical  exploration,  131 

proximal,  131 

records,  134,  528 

regional  divisions  for,  131 

at  stated  periods,  131 

system  and  method,  132 

systematic  record,  131 
Excessive  overbite,  771 
Excision  of  root,  369 
Exclusion  of  moisture  from  teeth  during 

operations,  149 
Expanded  arch,  retention  of,  828 
Expansion: 

arch,  spurs  and  hooks  for,  857 
vertical  alignment  of,  701 
Extension  for  prevention,  171 
External  anatomy,  relations  of  (orthodon- 
tia), 621 
Extraction,  419 

after-pains  of,  454 

after-treatment  of,  455 


Extraction,  alveolar  hemorrhage  from,  452 

casualties  attending,  451 

compl  cations  in  treatment  after,  814 

deciduous,  447 

— cuspids,  results  of,  808 
— laterals,  results  of,  808 
— molars,  results  of,  810 

first   permanent   molars,    results   of, 
812 

of  impacted  teeth,  459 

of  wrong  tooth,  451 

permanent,  evil  effects  of,  811 

problem  of  (orthodontia),  806 

roots,  448 

second  bicuspids,  result  of,  813 

shock  during,  452 

sterilizing  instruments  for,  455 

under  anesthetic  agents,  455 
Extruding  bicuspids,  727,  728 
Eye-strain,  87 

Facial  asymmetry,  623 

— profile,  619 

— symmetry,  619 
Faucial  tonsil,  hypertrophy  of,  640 
Fees,  537 
Fibroblasts,  83 
Filling: 

deciduous  teeth,  387 

the  impression  (orthodontia),  86f 

large  canals,  372 

materials,  229 

the  matrix  for  inlays,  284 

root  canals,  355,  371 

small  canals,  373 

the  use  of  the  matrix  for,  259 
Fillings,  preparation  of  cavities  for,  165 
Fissure  cavities,  170 

preparation  of,  187 
Fixation: 

of  expansion  arch,  703 

principle  of,  681 
Floor  of  pulp  chamber,  24 
Fluxes,  852 
Force  and  resistance  (orthodontia),  668 

appliances  for  producing,  670 
Forcing  teeth  or  roots  into  antrum,  452 
Forms  of  the  matrix,  260 
Fracture  (extraction): 

of  alveolar  process,  451 

of  crown  of  tooth,  451 

of  jaws,  451 
Frenum  labium,  abnormal,  649 

operation  for,  763 
Full  bimaxillary  infra-occlusion,  656 
Functional  influences  (orthodontia),  630 
Fundamental   pathological   conditions  in 

malocclusion,  650 
Furnaces,  299 
Furnaces,  electric,  302 

gasoline,  303 
Fusing  porcelain,  286 
Fusion  of  the  roots,  cemental,  451 

Gasoline  dental  furnace,  303 
Gassing,  301 
Gelatinous  plaques,  123 


INDEX 


885 


General  anodynes  or  analgesics,  226 
Gingival  margin,  2 
Glossary  (Rontgen  ray),  600 
Gold,  229 

and  amalgam,  256 

and  cement,  256 

and  platinum,  255 

and  tin,  256 

inlays,  construction  of,  305 
Green  stain,  108 
Growth  of  dental  arches,  606 
Gutta-percha,  253 

and  cement,  257 

fillings,  266 

for  separating,  138 
Gum  lancets,  450 

Hand  matrix,  263 

Harmony  of  facial  profile,  619 

Hawley's  diagram,  658 

Heat,  220 

Heredity  (orthodontia),  627 

Histological  constituents  of  dentin,  69 

Histology  of  the  human  teeth,  60 

Hoes   in  rubber  dam,  150 

distance  between,  151 

location  of,  152 
Hooks  for  expansion  arch,  857 
Human  denture,  normal,  i 

teeth,  the  anatomy  of,  i 

— the  histology  of,  60 
Hygiene  of  the  mouth,  97 

in  operating  room,  85 
Hypertrophy  of  faucial  tonsil,  640 

of  turbinated  bones,  641 
Hypodermic  armamentarium,  406 

Injection,  technique  of,  408 
Immunity  to  decay,  period  of,  124 
Impacted  lower  third   molars,  treatment 
of,  459 
definition,  459 
class  I,  460 
class  II,  462 
Implanting  teeth,  477 
Impressions  (orthodontia): 
assembling  the,  868 
filling  the,  869 

materials  and  models  for,  865"! 
sectioning  and  removal  of,  870 
tray,  866 

varnishing  tray,  869 
Imcisor: 

lower  central,  10 

— cervical  margin,  12 
— deciduous,  56 
— distal  surface,  12 
— incisive  edge,  12 
— labial  surface,  10 
— lingual  surface,  11 
— mesial  surface,  12 
— pulp  cavity,  13 
— root,  13 
lateral,  13 

— deciduous,  57 
mesial  and  distal  movements  of  (or- 
thodontia), 606 


Incision : 

upper  central,  3 

— cervical  margin,  6 
— cervical  ridge,  4 
— cingulum,  4 
— deciduous,  54 
upper  central,  distal  surface,  5 
— labial  surface,  3 
— lingual  surface,  4 
— mesial  surface,  5 
— pulp  canal,  6 
— pulp  cavity,  6 
— pulp  chamber,  6 
— root,  6 
lateral, 7 

— cervical  margin,  9 
— deciduous,  54 
— distal  surface,  9 
— incisive  edge,  9 
— labial  surface,  7 
— lingual  surface,  8 
— mesial  surface,  9 
— pulp  cavity,  10 
— root,  9 
Incisive  edge,  2 

Indications  for  the  planting  of  teeth,  478 
Infant,  oral  hygiene  of  the,  97 
Inflammatory  changes  in  alveolar  tissue, 

631 
Influence  of  the  pituitary  body,  629 
Infra-occlusion,  653 
anterior  teeth,  759 

bilateral  of  bicuspids  and  molars,  653 
class  II  div.  I  (orthodontia),  776 
full  bimaxillary,  656 
of  incisors,  cuspids  and  bicuspids,  653 

and  cuspids,  757 
of  molars  and  bicuspids,  761 
treatment  of,  728,  733 
variations  of,  653 
Inharmony  of  the  profile,  623 
Inlays,  267 

gold,  construction  of,  305 
indications  for  use  of,  267 
porcelain,  281 
posts  for  cast  gold,  311 
preparation  of  cavities  for,  271 
the  Taggart  method,  306 
Irritants,  drug,  343 

mechanical,  344 
Instruments: 

employed  for  extraction  of  teeth,  430 
for  preparation  of  cavities  for  fillings, 
1 82 
— chisels,  183 
— cutting  edge,  183 
— handle,  183 
— hatchets,  183 
— hoes,  183 
— shank,  183 
— spoons,  183 
sterilization  of,  93,  455 
Intermajtillary,  anchorage  (orthodontia 
687 
retention,  826 
Internal    anatomy,    relations    of    (ortho- 
dontia), 621 


886 


INDEX 


Interproximal  spaces,  53 
Intra-uterine  influence  upon  arch  develop- 
ment, 626 

Lancets,  450 

Large  canals,  filling  of,  372 

Lateral  incisors: 

deciduous  lower,  57 
upper,  54 

the  lower,  13 

the  upper,  7 
Layer  of  Weil,  77 
Lever,  726 

Ligating  the  teeth,  154 
Ligatures,  710 

as  auxiliaries  in  anchorage,  694 

care  of,  878 

variety  of,  710 
Light,  221 
Lingual  bar  and  ligature,  714 

arch  retainer,  833 

movements  of  incisors,  732 
Lip-biting,  648 
Local  anesthesia,  393 

anodynes,  223 

means  of  producing,  395 
Location  of  holes  in  rubber  dam,  152 
Loops,  bending  of,  731 
Lower  cuspid,  17 

first  bicuspid,  27 
molar,  44 

second  bicuspid,  30 
molar,  49 

third  molar,  52 

Magill  band,  854 

accessories  to,  856 
Malocclusion,  611 

classification  of,  651 

fundamental  pathological  conditions 
in,  650 

local  factors  In,  646 
Malrelation  of  dental  arches,  651 
Management    of    large    proximo-occlusal 
cavities  in  pulpless  bicuspids,  217 

in  pulpless  molars,  217 

of  an  ofiice  practice,  519 
Mandible: 

double  resection  of,  801 
Mastication,  discomfort  in,  388 
Materials  for  construction  of  appliance 
(orthodontia),  848 

for  filling  deciduous  teeth,  387 
Matrix : 

definition  of,  259  _ 

details  as  to  manipulation  of,  264 

employment  of,  for  gold  restorations, 
265 

filling  of,  for  porcelain  inlay,  284 

the  hand,  263 

introduction  and  management  of,  264 

materials  and  forms  of,  260 

mechanical,  260 

for  porcelain  inlay,  281 

removal  of,  265 

the  use  of,  in  filling  teeth,  259 
Measuring  the  force  of  expansion,  717 


Mechanical: 

advantage  (orthodontia),  692 

irritants,  344 

separator,  142 

advantages  of,  145 
Medication  (pyorrhea  alveolaris),  503 
Menthol,  225 

Mesial  and  distal  movements  of  incisors, 
716 

of  anterior  teeth,  732 
Metals  for  appliances,  choice  of  (ortho- 
dontia), 848^ 
Method  of  anesthetizing  the  pulp,  415 
Methods  of  removing  the  pulp,  326 
Mixing  of  plaster,  866 
Models  (orthodontia): 

marking  and  numbering  of,  876 

necessity,  for  accurate,  864 

trimming  the,  872 
Moisture,  exclusion  of,  from  the  teeth, 

149 
Molar: 

clamp  band,  859 

assembling  parts  of,  859 

deciduous,  55,  56,  57,  58 

distal   movements  of    (orthodontia), 

723 
lower  first,  44 

— buccal,  47 

— distal,  48 

— lingual,  48 

— mesial,  48 

— occlusal,  44 

— pulp  cavity,  49 

— roots,  48 
second,  49 

— buccal,  50 

— distal,  50 

— lingual,  50 

— mesial,  50 

— occlusal,  49 

— pulp  cavity,  52 

— roots,  50 
third,  52 

— pulp  cavity,  52 

— roots,  52 

— surfaces,  52 
upper  first,  31 

— buccal,  34 

— cusps,  32 

— distal,  36 

— fossae  and  grooves.  ^^ 

—lingual,  35 

— mesial,  35 

— occlusal,  31 

— pulp  cavity,  37 

— roots,  36 
second,  38 

— buccal,  39 

— distal,  40 

— lingual,  40 

— mesial,  40 

— occlusal,  38 

— pulp  cavity,  41 

— roots,  41 
third,  41 

— buccal,  42 


INDEX 


887 


Molar: 

upper  third  distal,  43 
— lingual,  42 
— mesial,  43 
— occlusal,  42 
— pulp  cavity,  43 
— roots,  43 
Mouth-breathing,  635 

examination  for,  768 
Mouth,  hygiene  of,  97 
Mouth-wash,  preparation  for,  106, 107, 880 
Muscular   action,   normal    (orthodontia), 

.630 
Mutilation  of  the  maxillary  tuberosity,  45  2 

Nasal  breathing,  obstructions  to,  638 
Nasal  septum,  deviation  of,  640 
Nearly  exposed  pulps,  treatment  of,  319 
Necessity,    for    accurate    models    (ortho- 
dontia), 864 
for  retention  (orthodontia),  820 
Neck  of  the  tooth,  2 
Nerves  of  the  pericementum,  84 
Nerves  of  the  pulp,  79 
Nitrous  oxid,  227 
Nomenclature: 

cavity,  165,  167 
Normal  development  of  associated  anat- 
omical structures  of  the  internal 
face,  615 
human  denture,  i 

muscular   action    (orthodontia),   630 
occlusion,  characteristics  of,  611 
overbite,  768 
Notification  of  patients,  535 
Novocain  preparation,  technique  of  injec- 
tion of,  408 

Obstructions  to  nasal  breathing,  638 
Obtundants,  496 
Occipital,  anchorage,  689 

retention,  827 
Occlusal: 

relations,  607 

— of  permanent  teeth,  609 
retention,  822 
surface,  2 

— cavities,  preparation  of,  212 
Occlusion : 

definition  of,  611 

line  of  (orthodontia),  666 

normal,  514,  610 

— characteristics  of,  611 
transition  period  of,  608 
Office  practice,  management  of,  519 
Oil  burners,  304 

of  cloves,  225 
Operating  chair,  the  window  in  front  of,  86 
room,  asepsis  in,  89 

hygiene  and  arrangement  of  light 
in,  8s 
Operation  for  abnormal  frenum  labium, 

763 
Operative: 

technic  (orthodontia),  696 
treatment,  technic  of  (orthodontia), 

790 


Opium,  226 

Oral  hygiene  of  the  infant,  97 

Ordinary  pericementitis,  treatment  of,  343 

Orthodontia,  603 

scope  of,  603 

trend  of  modern  theory  and  practice, 
604 
Orthopedia,  dento-facial,  617 
Osteoblasts,  83 
Osteoclasts,  83 
Oxidation  method  (discolorations),  380 

removal  of,  850 

Pathology  of  dental  caries,  119 
Pericemental  abscess,  treatment  of,  370 
Pericementitis,  343 
Pericementum,  80 
Period  of  immunity  to  decay,  124 
Permanent  teeth,  during  childhood,  treat- 
ment of,  389 

evil  effects  of  extraction  of,  84 
Personal  treatment  of  patients,  525 
Phenol,  222,  225 
Physical : 

agents,  220 

explorations  of  teeth,  131 

relations  of  beauty,  617 
Physiologic  action  of  anesthetics,  396 
Pit  and  fissure  cavities,  preparation  of,  187 
Pituitary  body,  influence  of,  629 
Plain  bands  (orthodontia),  854 
Planes,  relation  of  inclined,  612 

of  the  teeth,  168 
Planting  of  teeth,  473 
Plaster: 

mixing  of,  866 

technic,  864 
Platinum  and  gold,  225 
Plier,  arch-removing,  704 
Pneumatic  spray,  879 
Porcelain: 

bodies,  297 

inlay,  281 

section  attachment,  291 
Position  of  operator  and  patient  (extrac- 
tion), 429 
Posts  for  cast-gold  inlays,  311 
Post-natal  factors  in  arch  development, 

627 
Practical  case,  ideal  treatment  of,  78 
Preparation  of  cavities: 

in  bicuspids  and  molars  which  involve 
in  the  occlusal  surface,  212 

in  bicuspids  and  molars  which  do  not 
ir^volve  the  occlusal  surface,  210 

buccal  and  lingual  margins,  171 

bevel  and  polish  of  enamel  wall,  178 

burs  for,  185 

cavity  nomenclature,  165,  167 

classification  of  cavities,  166 

definitions,  165 

dental  engine,  185 

developmental  grooves,  171 

divisions,  of  cavities,  168 
—of  the  teeth,  168 

extension  for  prevention,  171 

for  fillings,  165 


888 


INDEX 


Preparation  of  cavities: 
fissure  cavities,  170 
general  conditions  of  outline  form, 

168 
for  inlays,  271 
instruments  for,  182 
lower  incisor  and  cuspid  cavities,  202 
management  of  large  cavities  in  pulp- 
less  molars,  217 
management  of  large  proximo-occlu- 
sal  cavities  in  pulpless  bicuspids, 
217 
proximal  cavities  in  incisors  and  cus- 
pids   which    involve   the   incisal 
angle,  202 
proximal  cavities  which  do  not  in- 
volve the  incisal  angle,  195 
pulpless  incisors  having  large  proxi- 
mal cavities,  209 
resistance  form,  175 
retention  form,  177 
sharpening  of  instruments,  186 
Preparation  of  cavities: 

smooth  surface  cavities,  191 
steps  in  cavity  formation,  168 
Preparation  for  mouth  wash,  106,  107 
Precautions  in  planting  teeth,  478 
Premature  loss  of  deciduous  teeth,  647 
Preservative     forces     of     arch     integrity 

(orthodontia),  613 
Prevention  of  thumb-sucking,  648 
Principle  of  fixation,  681 
Problem  of  extraction  (orthodontia),  806 
Procedure  for  planting  teeth,  479 
Profile,  inharmony  of,  623 
Prognosis,  caries,  129 

in  planting  of  teeth,  476 
Prolonged  retention  of  deciduous  teeth, 

646 
Proper  bevel  and  polish  of  enamel  wall,  178 
Prophylaxis,  878 
Proximal  surface,  2 

Proximo-occlusal  cavities  in  pulpless  bi- 
cuspids, 217 
Pulp,  76 

anesthetization  and  devitalization  of, 

325.  326,  334,  415 
capping  the,  320 
complications  incident  to  removal  of, 

338 
conditions  necessitating  removal  of, 

325 
methods  of  removing,  326 
nerves  of,  79 
partially  alive,  359 
removal  and  subsequent  treatment  of, 

325 

treatment  of  putrescent,  355.  359 
Putrescent  pulp  in  deciduous  teeth,  treat- 
ment of,  366 
Pyorrhea  alveolaris,  487 

diagnosis  of,  493 

etiology  and  pathology  of,  487 

medication  for,  503 

obtundents  for,  496 

retainers  for,  496 

subsequent  treatment,  505 


Pyorrhea   alveolaris    surgical    treatment, 
498 
systemic  treatment,  506 
treatment  of,  493 

Qualifications  of  appliances  (orthodontia), 

692 

Radiographic  diagnosis,  666 

Readings  from  casts,  864 

Reception  of  patients,  524 

Reciprocal  anchorage,  690 

Reduction  method  (discolorations),  380 

Re-inforced  anchorage  (orthodontia),  683 

Relations: 

of  beauty,  physical,  617 

of  external  and  internal  anatomy,  621 

of  inclined  planes,  612 

of  internal  secretory  organs  to  mal- 
occlusion, 628 

of  overbite  and  length  of  tooth  cusps, 
614 
Relative  value  of  first  permanent  molar, 

811 
Removal : 

of  adventitious  growths,  643 

of  deposits,  114 

of  impression  (orthodontia),  870 

and  subsequent   treatment   of  pulp, 

325 
— anesthetization  for,  326 
— complications,  incident  to,  338 
— conditions  necessitating,  325 
— methods  of,  326 
Repairing    defects    in    impressions    and 

models  (orthodontia),  876 
Replanting  teeth,  473 
Resection  of  the  mandible,  double,  801 
Resistance,   form   for   prepared   cavities, 
175,  203 
comparative  measures  of  (orthodon- 
tia), 679 
values   in    anchorage    (orthodontia), 
576         _ 
Results  of  extraction  of  deciduous  cuspids, 
laterals  and  molars,  808,  810 
of  first  permanent  molar,  812 
of  second  bicuspids,  814 
Retainer,  the  lingual  arch,  833 
Retainers  (pyorrhea  alveolaris),  496 
Retaining  appliances,  construction  of,  861 

wires,  731 
Retention  form  for  prepared  cavities,  177, 

204 
Retention  (orthodontia),  820 

after  anterior  expansion,  719 

after  bodily  movements  of  teeth,  828 

anterior  part  of  developing  arch,  829 

anterior  part  of  permanent  arch,  83a 

classified,  822 

of  changes  in  the  occlusal  plane,  836 

of  class  II,  838 

of  class  III,  846 

of  corrected  infra-occlusion  of  molars, 

837,  845, 
of  corrected  infra-occlusion  of  bicos- 
pids,  845 


INDEX 


889 


Retention  (orthodontia),  expanded  arch, 
828 
field  of,  827 
intermaxillary,  826 
intermaxillary  in,  class  II,  840,  844 
of  entire  deciduous  arch,  830 
of  entire  permanent  arch,  834 
of  malocclusion  of  individual  teeth,  828 
of  mesio-distal  changes  in  occlusion, 

827 
necessity  for,  820 
occipital,  827 
occlusal,  822,  824 
reciprocal,  825 
simple,  824 
Rontgen  ray,  541 
adjustment,  556 
apparatus,  546 
box,  developing,  570 

— examining,  582 
characteristics  of  X-ray,  584 
coil,  547  . 

compression  diaphragm,  559 
current,  inverse,  554 
dangers,  542 

developers,  temperature,  573 
developing  agents,  testing,  579 
developing  paraphernalia,  571 
electrical  units  of  measurements,  601 
films,  560 

— bromide  paper,  576 

— care  of,  563 

— consulting  photographer,  576 

— cutter,  564 

— deterioration  of,  576 

— enclosing,  564 

— hardening,  574 

— holders,  561 

— lead  backing,  576 

— making  photographic  prints,  576 

—packet,  565 

— preparation  board,  563 

— sizes  of,  576 

—testing,  577 
fluoroscope,  550 
focal  distance,  569 
glossary,  600 
head  rest,  549 
history  of  Rontgen  ray,  541 
hypo,  test  for,  574 
interrupter,  547 
inverse,  557 

—current,  554 
measurements,  electrical  units  of,  601 
meters,  549 
nomenclature,  541 
penetrameter,  551 
peridental  membrane,  583 
plant,  545 

— testing  of,  565 
posing  the  patient,  567 
ray,  secondary,  584 
rays,  strength  of,  556 
rheostat,  548 
room,  X-ray,  545 
ruby  lamp,  testing,  581 
safety  of  operator,  544 


Rontgen  ray: 

safety  of  patient,  544 
screen  protection,  551 

—intensifying,  553 
skiagraphs: 

— examining,  581 

—filing,  577 

—improving,  575 

— interpretation,  582 

— marking,  578 

— recording,  579 

—taking,  570 
stereographs,  593 
third  terminal,  557 
tubes: 

— connecting  X-ray  tubes,  55'* 

— exclusion,  559 

—rock,  558 

—stand,  557 

— suggestions  for  use,  555 

—X-ray,  553 
uses  of  ray,  584 
vacuum,  regulation,  556 

— to  raise  vacuum,  555 
value  of  ray,  584 

visible  hemisphere,  556 
X-ray  room,  545 

tubes,  553 
Root,  2 

absorbed,  368 
artificial,  484 
denuded  end  of,  367 
excision  of,  369 
encystment  of,  368 
Root  canals,  filling  of,  371,  372,  373 
Rotation  of  molars  (orthodontia),  725 
of  incisors,  731 
of  teeth  with  levers,  726 
Rubber  dam: 

the  use  of,  150 
adjusting,  152 
cervical  clanips,  158 
clamps,  157 

distance  between  holes,  151 
holes,  150 

ligating  the  teeth,  154 
location  of  holes,  152 
number  of  teeth  isolated,  152 
rubber  cups,  cotton  rolls,  napkins,'i6o 
saliva  ejector,  bibs  and  accessories,  160 
size  and  shape  of,  150 
use  of  absorbents,  161 
Rubber  for  separating,  140 

Sajou's  theory,  642 

Saliva,  chemical  composition  of,  no 

ejector,  160 
Scope  of  orthodontia,  603 

retention  (orthodontia),  820 
Screw  post,  technique  of  inserting,  217 
Secondary  abscess  pocket,  369 
Sectional  arch  and  its  advantages,  728^ 
Sectioning    and    removal    of   impression, 

(orthodontia),  870 
Sensitive  dentin,  treatment  of,  219 
Separation  of  teeth,  137 

cotton  for,  139 


890 


INDEX 


Separatiop  of  teeth,  gutta-percha  for,  138 

miscellaneous    conditions    requiring, 
146 

previous-slow  wedging,  138 

rubber  for,  140 

tape  for,  141 

wood  for,  141 
Separator: 

the  best,  142 

the  mechanical,  142 
Serumal  deposits,  112 
Shading,  295 

Sharpening  instruments,  186 
Shock  during  tooth  extraction,  452 
Shoeing,  208 
Silver  nitrate,  223 
Simple  anchorage,  683 

retention,  824 
Simplified  method  (orthodontia),  659 
Smooth  surface  cavities,  191 
Socket,  drilling  of  the  (planting),  480 
Soldering  the  band,  855 

requirements,  849 

technic,  851,  861 
Spaces,  developmental  (orthodontia),  606 
Sprays,  pneumatic,  879 
Spurs,  713 

for  expansion  arch,  857 

pliers,  713 
stationery,  538 

Steps  in  cavity  formation,  168 
Stereographs,  593 

Sterilization  of  instruments,  93,  455 
Sterilizing  agents,  485 
Stomatitis,  106 

Subsequent  treatment  (pyorrhea),  505 
Summary  of  anchorage  principles,  695 
Superficial  defects,  170 
Supernumeraries,  648 
Surfaces  of  teeth,  2 

buccal,  3 

labial,  2 

lingual,  3 

proximal,  2 
Surgical  treatment  (pyorrhea),  498 
Symmetry  of  the  face,  617,  619 
Symptoms    of    developing    malocclusion 

deductions  from,  625 
Syncope,  451 
Systemic  treatment  (pyorrhea),  506 

Table  of  average  measurements,  661 
Taggart  method,  cast  inlay,  306 

difficult  cavities  filled  by,  309 
Tape,  141 
Technique: 

constructive,  847 

instruction,  advantages  of  (orthodon- 
tia), 847 

plaster,  864 

of  inserting  a  screw  post,  217 

of  novocain,  injection,  408 
Teeth: 

anatomy  of  the  human,  i 

anatomical  parts  of,  2 

arches  of  temporary,  605 

deciduous,  53 


Teeth: 

eruption  of,  428 

examination  of,  to  discover  carious 

cavities,  131 
extraction  of,  419 

— deciduous,  447 
forcing  into  antrum  (extraction),  452 
histology  of  the  human,  60 

— impacted,  extraction  of,  459 
implanting  of,  477 
loss  of  permanent,  647 
materials  for  filling  deciduous,  387 
neck  of,  2 

occlusal  relations  of  permanent,  609 
planting  of,  473 
replanting  of,  473 
separation  of,  133 
transplanting  of,  477 
treatment  of  discolorations  of,  375 
treatment  of  putrescent  pulps  and 

abscesses  in  deciduous,  367 
use  of  matrix  in  filling,  259 
Temporary  teeth,  arches  of,  510 
Therapeutics  for  obtunding  sensitive  den- 
tin, 220 
Thrush,  104 
Thumb-sucking,  648 
Tin,  249 

Tipping  up  molars  (orthodontia),  724 
Tooth: 

alveolar  hemorrhage  from  extraction 

of,  452 
angle  of,  2 

casualties  attending  extraction  of,  451 
escape  of  into  larynx  or  pharynx,  451 
extraction  of  the  wrong,  451 
Treatment: 

of  children's  teeth,  385 
of  discolorations  of  teeth,  375 
of  exposed  or  nearly  exposed  pulps,  319 
of  infra-occlusion,  728,  733 
— complications  in,  after  extraction 

of  teeth,  814 
— early  of  class  II,  768 
— of   arrested   development,   early 

(orthodontia),  735 
— of  class  I,  738 
— of  class  II,  765,  768 
— of  class  II,  div.  I,  776 
— of  class  II,  div.  I,  sub.  div.,  781 
— of  class  II,  div.  II,  782 
— of  class  II,  div.  II,  sub.  div.,  785 
— of  class  III,  789 
— of  class  IV,  805 
— impacted  lower  third  molars,  459 
— of  special  cases,  742,  772 
— technic  of  operative,  776,  790 
of  permanent  teeth  during  childhood, 

389 
of  pyorrhea  alveolaris,  493 
— erosion,  515 
— subsequent,  505 
— surgical,  498 
— systemic,  506 
of  sensitive  dentin,  219 
Trichloracetic  acid,  223 
Trimming  the  model  (orthodontia),  278 


INDEX 


891 


Unilateral  expansion  of  the  dental  arch,       Varnishing  the  impression  (orthodontia) 
721  869 

Use  of  the  matrix,  259 

of  the  rubber  dam,  150 

Uses  of  intermaxillary  anchorage  (ortho- 
dontia), 687 

Utilization  of  time  in  the  ofSce,  526 


Variations  of  infra-occlusion,  653 

of  overbite,  755 
Variety  of  ligatures,  710 


Weil,  the  layer  of,  77 
Window  in  front  of  operating  chair,  86 
Wood  for  separating,  141 
Wrenches,  709 

Young  blowpipe,  850 

Zinc  chlorid,  222 


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e.pirn°:'rdefinitepeHodaf^rthed^^^ 
as  provided  by  the  rules  of  the  Library  or  oy    p 
rangement  with  the  Librarian  in  charge. 


C2a(239)M100 


RK501 
Johnson 


.     J62 
1915 


A  text-book  of  operative  dentistry 


2002399318 


AUG  4    ICZ? 


